# Forum Home Renovation Heating & Cooling  Reverse cycle units and we're still cold!

## Cecile

Because of the layout of our house, we chose to install five split systems rather than gas ducted for winter and separate splits for summer.  At the time, cooling was most important (these work VERY well for cooling) but I was a little dubious about the ability of reverse cycle to heat well.  It's not even very cold yet, but I am already finding that, instead of warming the room as a whole, they are more like spot heaters and there are pockets of cold everywhere.  If I set them on what I think might be a reasonable temperature (19 or 20) the blowing air feels cold two metres away.  I don't know if turning them up to 24 would fix the problem, but in my mind 24 is simply too warm. 
I don't really know if this is going to be a trial and error thing, or if I am simply not using them correctly.  Not sure if the old "RTFM" is the answer here, as every house/layout is different.  The mind boggles at the concept of having five splits running day and night, and the accompanying OMG when the power bill arrives! 
Any input/feedback gratefully accepted.

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## JB1

Yes, it does warm up OK, but I think gas is a nicer type of heat  (hydronic radiant panels is suppose to be nicer again) and quieter too. 
I think it also comes down to the fact splits blows less hot air than a 150mm or 200mm duct. 
Try turning it up to 21-22 and see it that helps. Also try pointing the vent to point slightly downwards. 
BTW like you, I only have splits for heating and cooling. I'll live with it due to the money I've saved. I only turn on splits in rooms we are in. I.e. living area during the day and bedrooms at night. 
That reminds me, I have to clean the filters. 
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## johnc

We have a split system which was installed for cool but opted for the heat function as well, the house already had wood heating as well as ducted gas. I'd have to say we don't find the heat function very satisfactory for the reason you mention there seems to be hot spots and the heat seems more oppressive. We mainly opt for the wood heater and use the ducted system to warm the house when we first get home from work then allow the wood heater to maintain that heat for the rest of the night and often to keep the living areas warmish over night. 
Whatever may have been the best option doesn't really matter now, have you considered installing a gas wall heater in your living area or a small ducted system that only heats the living areas. Given you have a health condition that effects temperature regulation there probably isn't a perfect outcome for all seasons.  Your problem will be lack of air movement and the creation of still patches or air something a ducted system tends to overcome with proper placement of the air inlet.

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## Cecile

> proper placement of the air inlet.

  Ah, the air inlet.  The main reason why we didn't go ducted in the first place!  Depending on how we go over the winter, I'm still considering a small gas ducted system for our main living areas and master bedroom.  As we do more renovation, the house is becoming more or less air tight. 
Thank you for your input.

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## Smurf

Split systems can heat well if you have the right unit and "drive" it the right way..... A few tips. 
1. Assuming a wall mounted unit, the air flow needs to be pointed toward the floor when in heating mode. Typically, you want it pointed as far down as it will go, not straight down, but close to it. So 10 degrees or so from vertical. With most systems, this is as far is it goes so adjust it to that position. 
2. The fan needs to be set to either "Auto" or to the highest setting. If you want it to heat well then never set the fan to low speed - that results in poor heat distribution and also runs up the power bill since it makes the compressor (which uses far more energy than the fan) work harder. 
3. Make sure the filters are clean and not obstructing the airflow. 
4. Set the mode of the system to "Heat" not to "Auto" and you'll find it works much better with most systems.  
5. The thermostats aren't too accurate in heating mode so ignore it and just set it to whatever setting provides sufficient heat. You won't break the machine even if you turn it all the way up to 30. I suggest getting a normal thermometer to keep a check on the actual temperature inside the house, and just set the split system to whatever is required to keep it comfortable. The colder it gets outside, the higher you'll need to set the system in order to maintain (say) 22 degrees inside. 
The reason for the thermostat inaccuracy is simply because the temperature probe is inside the unit itself, thus measuring the temperature there rather than 5 metres away in the room. It works reasonably well in cooling mode, but they're not so accurate for heating. So just turn it up. 
As for the running costs, I'm not sure of your electricity prices in Victoria but here in Tas split systems are the single most common means of heating a home, with around a 45% market share (significantly higher in privately owned properties, less common in rentals where landlords see no benefit in installing an expensive to purchase means of heating).  
The reason is pretty simple since reverse cycle air-con (or "heat pumps" as they are universally called in Tas) are cheaper than most of the alternatives in terms of running costs. Using Tas prices, firewood at $130 per tonne is a similar cost to running a heat pump on electricity that costs 16 cents per kWh. Everything else (mains gas, LPG, pellets, other electric heaters, oil) is significantly more expensive than a heat pump. Hence the popularity of them in privately owned houses - very few people down here buy them for cooling, they are marketed as heating appliances and people buy them for that purpose with cooling just a rarely used bonus. 
Brand of the system also makes a difference especially in very cold weather (approaching zero). Daikin and Mitsubishi work very well in cold weather with Panasonic also pretty good. No comment for anything else, but certainly there are some that don't work at all well in cold conditions. 
For the record, heating market share in Tas: 
Electric = 66% of which heat pumps account for about two thirds of that. The rest is split between large built-in fan heaters (typically 6kW but there are some units up to 10kW in ordinary homes), portable heaters and off-peak storage heaters. The trend in recent years is to replace other electric systems with heat pumps simply to save energy - there's always plenty of big fan heaters etc for sale secondhand although most probably end up at the tip. 
Wood = 29% of which slow combustion heaters are the vast majority. Pellets have a bit under 1% of the market. 
Gas = 4% split about half and half between mains gas and LPG. Natural gas has a growing market, Tas Gas is advertising pretty aggressively in recent times trying to get more homes connected to gas, whilst the LPG market has declined as costs have gone up. 
Oil = 1% and in decline since the 1970's when it was the dominant means of heating. At some point it will go to zero, it's inevitable sooner or later. 
So heat pumps (reverse cycle air-con) certainly does work as a means of heating in the coldest state of Australia. You just have to drive the system hard enough to keep you warm. As for the cost in Vic, you'd have to check your local power prices but it's definitely more expensive for electricity in Vic than it is down here in Tas where the heating tariff is 16.167 cents / kWh.

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## Cecile

Thanks Smurf.  Wonderful answer.  Confirms what I suspected, it's trial and error, more or less.

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## Moondog55

I am walking around inside in a T-shirt tho, so we will need to find a happy medium. I agree with Cecile. ;  a wonderful answer.
Part of the problem is of course being only half way through the re-plastering and lots of gaps and air leaks still from which we are losing far to much heat

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## manofaus

the whole problem is the hot air rising thing. you need to use the fan to push the hot air down so it mingles with the cold air and this will warm the room. Your intake for your air con will suck in the air that rises to the ceiling and reheat it and send it back down again. Convection is the enemy in winter. Summer it works a treat.
Most other heat types use radiant heat or are low to the ground.

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## Random Username

The problem I found with reverse cycle heating was that you don't really get a feeling of heat on really cold days.  It's not like gas, where the air comes out of the ducts at 30 odd degrees; with the RC it might be minus two outside, 14 degrees inside and...because of the cold outside the efficiency really drops off and it's only making incremental improvements in temperature.  Air might start coming out at 14.5 degrees, 15 minutes later it might be up to 15 degrees, another 15 minutes for another half degree improvement, and a few hours later it might almost be up to temperature.

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## Brian7886

> The problem I found with reverse cycle heating was that you don't really get a feeling of heat on really cold days.  It's not like gas, where the air comes out of the ducts at 30 odd degrees; with the RC it might be minus two outside, 14 degrees inside and...because of the cold outside the efficiency really drops off and it's only making incremental improvements in temperature.  Air might start coming out at 14.5 degrees, 15 minutes later it might be up to 15 degrees, another 15 minutes for another half degree improvement, and a few hours later it might almost be up to temperature.

  
On a split system air con your air temp shouldnt be anything like 14 degrees coming off the unit.  
Air cons have an indoor coil thermistor, and the indoor fan should not run until the coil is hot enough to blow hot enough air.  
We had a similar discussion about this unit when you had it installed IIRC.  
Things to be mindful of. How many units are running. If you ran all 4 (i think it was 4) heads at once, you do drop the overall efficiency of the unit.  
22 degrees is a pretty standard temp. The air wont always feel 'HOT'. Make sure you point the louvres down, or at least on an angle down, rather than straight out. Close ya blinds/curtains to stop cool temps off windows.  
Somewhat regrettably we have recently become a Fujitsu dealer (dropping Panasonic back in our sales order due to crazy price hikes). Ive installed them for years, but now will be selling them and obviously be doing alot more homework on them.

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## Random Username

> We had a similar discussion about this unit when you had it installed IIRC.

  Wasn't me. The last time I had air con installed was back in the late 90's.

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## Brian7886

> Wasn't me. The last time I had air con installed was back in the late 90's.

  sorry i meant the OP.

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## toooldforthis

just wondering if a ceiling fan might help circulate the warm air from the split system to help eradicate cold spots? even the cheap ones have a switch to change the rotation direction for cooling or heating circulation.
I am a big fan  :Doh:  of ceiling fans  :Biggrin:

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## Moondog55

A partial solution to the problem is simply doing as you suggested and adjusting the thermostat temperature up a degree or two, that is working  in two ways I think; it keeps the fan on high speed for longer and allows the warm air to move further away from the head which seems to break up the stratification that usually occurs
We did listen to your advice Brian; and it really was appreciated, but in the end we went for the system we could afford that gave the greatest over-all benefit in my opinion. Summer cooling being a medical need and all that
As I also said earlier I don't think we will be having a problem when I have finally got the house sealed up to a reasonable standard. Truth is I have been concentrating my efforts of the summer cooling side of things. A few dollars spent at Clark Rubber for some filler rod will help a lot as will some more tape along some edges.

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## Moondog55

> just wondering if a ceiling fan might help circulate the warm air from the split system to help eradicate cold spots? even the cheap ones have a switch to change the rotation direction for cooling or heating circulation.
> I am a big fan  of ceiling fans

  Good idea except I keep hitting my head on them when I walk under [ or have the fear of doing so ] and we may bring out the summer fan and see if that helps.

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## Bros

If things get really desperate you can do what thousands of other Victorians do and buy a caravan and head north for the winter. :Biggrin:  :Biggrin:

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## JB1

> Somewhat regrettably we have recently become a Fujitsu dealer (dropping Panasonic back in our sales order due to crazy price hikes). Ive installed them for years, but now will be selling them and obviously be doing alot more homework on them.

  I have 3x Fujitsu 2.6kw units and 1 Pana 8kw unit in my house. I also had experience with a 7kw Pana. 
Let me know what you think of the the Fujitsu's.  
It's too early to say which is more reliable for me, but I think the Fujitsu's just work better and quieter (of course taking into account the larger unit will be louder).  
The reason I didn't get the 8kw Fujitsu was it was about $300 more at the time of purchase.  
Not to say I'm not happy with the Fujitsu, but if price wasn't an issue, I'd choose the Fujitsu in future. Having said that both units are great for my purpose.       
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## Brian7886

Reliability wise, panasonic would be 1000x better. Ive got an 8kw panasonic and the outdoor unit is right behind my bed head. No noise.  
Fujitsu are a house hold name, thats why people buy them, but they are far from great. Panasonic, daikin, mhi, toshiba are all well beyond.  
We have been a service agent for along time for fujitsu, and to be frank, fujitsu account for close to 50% of our call outs.  
We recently became a dealer as fujitsu actually over their specialist dealers great buy price, panasonic favour the big sellers like bing lee and harvey norman etc.  
Outdoor boards and condensor fans are most prone to go in fujitsu, however their warranty is easy for us to deal with

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## toooldforthis

> Reliability wise, panasonic would be 1000x better. Ive got an 8kw panasonic and the outdoor unit is right behind my bed head. No noise.  
> Fujitsu are a house hold name, thats why people buy them, but they are far from great. Panasonic, daikin, mhi, toshiba are all well beyond.  
> We have been a service agent for along time for fujitsu, and to be frank, fujitsu account for close to 50% of our call outs.  
> We recently became a dealer as fujitsu actually over their specialist dealers great buy price, panasonic favour the big sellers like bing lee and harvey norman etc.  
> Outdoor boards and condensor fans are most prone to go in fujitsu, however their warranty is easy for us to deal with

  that was my experience at my last place.
boards blow when work done on elec supply to house (not the house itself).
fortunately tho still under warranty at the time - tho once they quibbled when they found a small lizard, about 75mm, inside.
wouldn't buy em again.

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## Cecile

> Fujitsu are a house hold name, thats why people buy them, but they are far from great. Panasonic, daikin, mhi, toshiba are all well beyond.

  When we were ordering our units I recall asking if Fujitsu was the best available, and we were reassured.  I'm not unhappy as they do work...the one in the living room is five years old and has run without a hiccup the whole time.  As I said, for cooling they have been really excellent this hot summer.  This winter will tell whether or not we made the right heating choice. 
Thanks everyone for your input.  Great, informative thread.

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## Brian7886

Thats salesman. For me it was strictly business for the decision to sell fujitsu, they will sell. But we wont be recommending them over the mhi.

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## Brian7886

Most brands will not cover vermin etc damage. Usually a service guy will clean it up and pretend it was never there. Do note that majority of brands require parts back for testing, and if they find evidence of vermin they wont pay the labour and will charge the repairer for the part.  
Hence where a specialist sales-install-service guy is the best option from the word go.....they will probably go out of their way to get it fixed under warranty

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## JB1

Thanks for the info Brian, I guess I should have got all Panasonic splits. 
Too late now, hopefully they will last  :Smilie:  
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## phild01

I have two fujitsu splits.  Both have also been de-gassed and relocated.  One is the old gas and is well over 10 years old (Japanese).  The other is a bigger new gas type (Taiwanese).  Both are incident free.
My sister had a Panasonic ducted that failed within 5 years. 
I doubt mine to be better than hers, just  think it comes down to quality of installation of lines and contamination of gas.

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## Brian7886

Im not saying they r no good, if they work they work well.  
But reliability is our issue as our business reputation needs to be good

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## Smurf

So far as reliability is concerned, here is my experience with Panasonic and Fujitsu systems. 
Panasonic. 4kW (heating capacity) unit installed late 1997 as the primary heating in a house with high thermal mass. It was left running 24/7/365 and during the coldest weather the heating was supplemented by an old off-peak storage heater used intermittently. There was a fault with the indoor control board sometime around 2004 (one component failed, replaced by me) and the compressor failed in early 2013. So 15.5 years of service with one fault before the unit died. During that time, the compressor was actually running 35 - 40% of the time for the whole 15.5 years so it had a LOT of use. 
It was replaced by a Daikin system, a bit over 6kW heating, and the off-peak heater is no longer used. 
Fujitsu. One system roughly 4kW heating (not sure of the exact rating) used intermittently in a commercial situation 8am - 6pm Monday to Friday. Indoor board has been replaced once and the system is still in use. 
Another fujitsu system roughly 6kW heating used at the same business. Indoor boards have been replaced 3 times but the unit is still in service. 
So in terms of reliability, I'd say that Panasonic does seem to be more reliable. The indoor boards on the Fujitsu are a shocking design in my opinion and far too prone to being "zapped" with inadequate isolation. 
In terms of heating performance, the larger Fujitsu system noticeably loses much of its' capacity at temperatures close to zero. Also the defrost cycle is long, 15 minutes or so. In contrast the Panasonic would simply stop no more than once per hour, do a defrost, and be back running full blast in about 3 minutes. 
So Panasonic is a better unit overall based on my experience although admittedly this is with late 1990's systems not current models. 
But if I was buying one today then I'd go for Daikin for sure. Simply because they dominate the market down here in Tas so there's far more Daikin dealers than anyone else should something ever break. A few Panasonic, Mitsubishi Electric and Fujitsu dealers, and only one Mitsubishi Heavy Industries dealer versus lots with Daikin so definitely a lot more backup locally. Walk around any Tassie suburb and you'll spot more Daikin systems than all other brands put together.... 
That plus the Daikin systems work very well under cold conditions. That is to the extent that the brand has always had the implicit backing of the (government owned) power industry - their "heat pump" promotions almost always visibly feature Daikin systems and make no secret of this (and no doubt the implicit backing of the Hydro and in more recent times Aurora Energy (electricity retailer) would have contributed to the popularity of Daikin systems in Tas).  :Smilie:

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## Brian7886

As a professional in this topic (not sticking my chest out). Daikin are not the cream of the crop. No better than pano, mhi or m.e. 
Daikins biggest downfall is its build. 4 pcb's in the outdoor which fail in sequence, usually in conjunction with a fan. Not such a drama under warranty but outside warranty parts are expensive!  
Mitsubishi electric is similar.  
Pano and mhi all have basically 1 outdoor pcb (untill u get to the 10kw or above systems).  
Toshiba have actually been real bloomers, they run the same pcb in all systems, which is programmable upon install, meaning service agents can carry 1 part that suits all systems.  
Basically there is a tree of air cons.  
Panasonic, mhi, daikin, m.e, toshiba 
Then fujitsu, lg, carrier, samsung.  
Then teco midea kelvinator actron(splits not ducted) 
Then ya sterlings, akai, dux, mistral etc  
We sell 3 from the top tier, 1 from the second and 2 from the 3rd. We leave the rest to bunnings lol

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## Brian7886

As for the daikin and government. Daikin have always been a government issue air con. Most places that are government building with daikins, the government body supplied the system as they import their own. I do plenty of contract work this way.  
However when doing schools, we are asked to quote daikins(which we dont sell) and 9/10 times get the job with mhi. Based on specs, price etc.  
Daikin have their rep for 1 reason, they have never sold through retailers, only specialist dealers. So generally anyone who has one has bought a suitable system, not bought whatever the idiot at harvey norman recomended

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## Smurf

I can see that Daikin may or may not be the "best" system, but in my case service backup is also a factor. 
Buy MHI and you're stuck with a single dealer down here if anything goes wrong. If they charge something ridiculous to fix it then there's not a lot of options when everyone else is doing Daikin, Panasonic, Mitsubishi Electric etc. 
As for the "bottom of the market" brands, can you even get spares for a Mistral etc? Maybe you can, but I'd have some doubts. 
I do take as very useful the comment about which are the good brands, second and third tier etc.  :Smilie:  
One thing is that, if you are buying an air-con primarily or solely for heating use, then cost is a key driver since saving money is the only real reason for having it in the first place. Based on what I've experienced personally and that of friends etc, these systems in general do seem to require at least one costly service visit after a few years. Paying $700 or so because the indoor board blew up puts a dent in the power savings when you consider that a standard electric heater generally won't need repairs during its' entire working lifespan. Same with a simple gas room heater with not much that can really go wrong until the whole thing wears out after a few decades. There are still a few old oil heaters from the 1970's in use today - it's all mechanical and electrical, nothing electronic, thus not much actually goes wrong with them.  
I'm sure that those who work with them daily could comment better than me, I've only repaired a few for friends etc (I'm an electrician but I don't do air-con for a living). But I know someone who scrapped their 6 year old system as uneconomic to repair and that seems an incredibly short lifespan for a costly appliance in my opinion. It wasn't a "top tier" system but it was a known brand.

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## phild01

> Based on what I've experienced personally and that of friends etc, these systems in general do seem to require at least one costly service visit after a few years. Paying $700 or so because the indoor board blew up

  Like to know the consensus on this one.  When buying an A/C, we should not be expected to factor in such a failure or expense.  I know the boards can fail but I would only expect this with a Gree or some other cheap unit.
So, if failure is common, what causes this event.  Are the units fine tuned to 220V and a higher voltage slowly burns them out. Electronics should be good for at least 15 years and more!

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## Smurf

I emphasise that I am not a professional A/C service tech, I'm just commenting based on my own observations. 
Thinking of people I know with older systems, that is those more than 10 years old, a lot of them have had a breakdown at some point and it's usually the electronics which fail. 
No doubt those who work with them regularly would have a better idea of the actual failure rates.  :Smilie:

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## Brian7886

> I emphasise that I am not a professional A/C service tech, I'm just commenting based on my own observations. 
> Thinking of people I know with older systems, that is those more than 10 years old, a lot of them have had a breakdown at some point and it's usually the electronics which fail. 
> No doubt those who work with them regularly would have a better idea of the actual failure rates.

  
most systems will have a hiccup at some point. servicing is ideal, clogged coils etc increase the pressure on the compressor and that also results in more current through components.  
pcbs fail like crazy, but sometimes its power problems in the house/street which factor in aswell. 
not many compressors fail these days, control boards are the big 1 and the manufacturer is making those parts expensive to replace.

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## Brian7886

> Like to know the consensus on this one.  When buying an A/C, we should not be expected to factor in such a failure or expense.  I know the boards can fail but I would only expect this with a Gree or some other cheap unit.
> So, if failure is common, what causes this event.  Are the units fine tuned to 220V and a higher voltage slowly burns them out. Electronics should be good for at least 15 years and more!

  
main factors.  
low voltage (excess current) causing burn outs
power spikes
mice/frogs/cockroaches
a faulty component might short out a board
water (due to not servicing it) 
boards will fail in anything. but as i said above, theres tiers of systems that we sell on a quality/reliability scale, and we tell all customers during the quote process.  
unlike computers, outdoor units are in the elements, things like salt air play havoc with boards big time. 
people think its high way robbery to want $90 to come and service a system, which for us includes using a pcb cleaner. but cry when they get a $1000 repair bill

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## Smurf

> most systems will have a hiccup at some point. servicing is ideal, clogged coils etc increase the pressure on the compressor and that also results in more current through components.  
> pcbs fail like crazy

  That's in line with my observations. With one exception (compressor), every failure I've heard (work, friends, family etc) of in a system under 15 years old has been a board fault. 
Another thing I suspect is how people use them. Eg if the fan is turned down to "low" then that's ultimately a restriction on airflow much the same as if the coils are clogged with dust etc. Either way you have less efficient heat exchange with all that goes with it.  
I did a trial once with a (non-inverter) system. Power consumption for 1 hour maintaining a steady room temperature (in heating mode) with fan on low versus fan on high. There was a significant drop in power use and compressor running time with the fan set to high whilst the outdoor temperature (measured) remained roughly constant. And yet practically every installer seems to be telling consumers to use low fan speed - something I don't really understand as it goes against logic (reducing the efficiency of heat exchange) and I've never heard of someone wearing the fan out by running it on high speed. 
As I said though, I'm an electrician (industrial) not an A/C service tech so this is just based on my own observations and a bit of experimenting. Since we have separate metering for heating in Tas it was easy to do the measurements - just read the electricity meter. 
PS - Judging by threads on this forum, gas ducted heating also seems prone to electronic faults. There's a constant stream of "gas ducted heater model x doesn't work" type threads versus hardly any relating to gas (or electric) space heaters. So gas ducted systems also seem reasonably prone to board faults etc.

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## Brian7886

> That's in line with my observations. With one exception (compressor), every failure I've heard (work, friends, family etc) of in a system under 15 years old has been a board fault. 
> Another thing I suspect is how people use them. Eg if the fan is turned down to "low" then that's ultimately a restriction on airflow much the same as if the coils are clogged with dust etc. Either way you have less efficient heat exchange with all that goes with it.  
> I did a trial once with a (non-inverter) system. Power consumption for 1 hour maintaining a steady room temperature (in heating mode) with fan on low versus fan on high. There was a significant drop in power use and compressor running time with the fan set to high whilst the outdoor temperature (measured) remained roughly constant. And yet practically every installer seems to be telling consumers to use low fan speed - something I don't really understand as it goes against logic (reducing the efficiency of heat exchange) and I've never heard of someone wearing the fan out by running it on high speed. 
> As I said though, I'm an electrician (industrial) not an A/C service tech so this is just based on my own observations and a bit of experimenting. Since we have separate metering for heating in Tas it was easy to do the measurements - just read the electricity meter. 
> PS - Judging by threads on this forum, gas ducted heating also seems prone to electronic faults. There's a constant stream of "gas ducted heater model x doesn't work" type threads versus hardly any relating to gas (or electric) space heaters. So gas ducted systems also seem reasonably prone to board faults etc.

  
the reason it would have used 'less power' especially in a fixed speed system is that it would have reached set point faster.  
ie, set it to 21 degrees, high fan blowing 50 degree air into the room, its heating more volume of air per second than on low. i tell people to use auto, not low. you dont need high fan once u reach temp. automfan will start on high and gradually drop to low as temperatures reach the desired level.

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## Moondog55

From your comments I have to assume the PCB boards are not "tropicalised" with lacquer to make them waterproof. Seems shortsighted for an outdoor unit.
What service interval do you suggest ? Every 6 months or yearly?
If it's 6 months perhaps we should have it done soon

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## phild01

Am wondering what a 'service' actually entails.  Surely not just the user cleaning of the head unit filters.
Is this a suggestion of servicing the circuit boards!
Can it be if the outdoor unit is in a very exposed area, that the design of the unit is insufficient to offer necessary protection from dust, rain and high temperature days.

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## Brian7886

> Am wondering what a 'service' actually entails.  Surely not just the user cleaning of the head unit filters.
> Is this a suggestion of servicing the circuit boards!
> Can it be if the outdoor unit is in a very exposed area, that the design of the unit is insufficient to offer necessary protection from dust, rain and high temperature days.

  clean sanitise filters
flush indoor drain pan and clean
clean indoor coil
check indoor electrical connections
clean indoor case and grille 
wash out door unit
polish outdoor unit
clean outdoor coil
check electrical connections
measure running currents
check/clean pcbs
check refrigerant pressures
clean out any nesting/eggs of insects etc
rust prevention spray if needed 
replace remote control batteries
test system through both cycles 
$90 usually takes an hour includes all the stuff required to do it and labour/call out.

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## Brian7886

> From your comments I have to assume the PCB boards are not "tropicalised" with lacquer to make them waterproof. Seems shortsighted for an outdoor unit.
> What service interval do you suggest ? Every 6 months or yearly?
> If it's 6 months perhaps we should have it done soon

  theyll never make them water proof, the unit shouldnt get water in a sealed pcb case.  
MHI have a silicone coating on their pcbs, which sees them hold up to the coastal climates alot better

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## phild01

How are the indoor coils cleaned?
How is the outdoor unit cleaned other than checking electrical, and polishing?
As for checking refrigerant, I like the idea of leaving as is unless the unit is not performing.

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## Moondog55

> theyll never make them water proof, the unit shouldnt get water in a sealed pcb case.  
> MHI have a silicone coating on their pcbs, which sees them hold up to the coastal climates alot better

  Water and moisture being 2 similar but different things I can't see why they shouldn't be lacquered, Panasonic have been doing so with their TVs for decades for use in tropical areas as it stops mould and mildew from penetrating the electrical circuit. 
However I concede that if the PCB case is sealed then it shouldn't be an issue.
So what is a reasonable service interval and would having a unit serviced on a regular basis increase its working life significantly?

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## Brian7886

12 monthy, with the owner regularly cleaning filters aswell.  
Some brands will now void warranty if not serviced by a lisenced person

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## phild01

> Some brands will now void warranty if not serviced by a lisenced person

  Wouldn't go with a brand if they said that. 
Sounds like it's going down the path of the auto industry.  Hold the customer to ransom with 5 year warranties.  By this I mean, build in maintenance issues that don't really matter much and make the customer pay hugely for the perceived service (these auto services also include listed times for work that exceed the actual times taken to do).  All adds up to a profitable rort for them - though just rambling about another matter that consequently stupefies society.  :Frown:  
Edit:  Took that post to mean that regular services must be performed during the warranty period rather than if serviced during warranty period. :Confused:

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## Brian7886

Not really.  
They wont void a warranty on a blown board cos the filters arent clean but they wont pay a  service agent if the unit isnt serviced and the problem is build up of dirt causing errors.  
Also most reputable brands will have something similar in their warranty terms and conditions.

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## Brian7886

By the way, we are paid flat rates for repairs that rarely cover the time taken. Warranty companies (not always the manufacturer by the way) are rorting agents every day

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## phild01

The only thing I recall according to my manufacturer's instructions is keep the filters clean.  I expect anything else should be a matter of manufacturing the product according to expected use.

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## Smurf

Fan speed - my test was done on a fixed speed compressor system (that is, an older (1997, Panasonic) model not the more modern variable speed type) and was simply maintaining a temperature that had already been reached (the system had already been running all day). Energy consumption was definitely reduced by increasing the fan speed in that case. 
In a less scientific manner I replicated this with another older (1999, Mitsubishi Electric) system at a friend's house. Their power bills were a problem and they asked me for some suggestions. The Tariff 42 meter (heating and they also have the hot water (normal electric system) on this rate) accounted for the vast majority of total consumption and Winter was several times higher than Summer, thus pointing to the air-con as the source of their high bills. I gave the system a reasonable cleaning indoors and out, and suggested that they try operating the fan on auto or high rather than the low setting they previously used. Power use over the 3 month billing period did drop noticeably, although there are of course other variables such as generally being more careful with use, weather etc and also I dropped the hot water thermostat from 70 down to 60 so it's hard to prove that the efficiency of the air-con increased. 
I'd assume however that the modern (inverter) systems with variable speed compressor would be "smart" enough to work out the most appropriate fan speed such that this would no longer apply? Eg set the fan to auto and presumably it will run most efficiently. That's an assumption that I haven't tested in practice but it seems reasonable - if it can work out the required compressor speed then presumably it will also adjust the fan appropriately if set to auto. 
As for PCB's, this is in a totally different situation (industrial control system) but a few years ago we had an extremely high failure rate with a particular product which includes multiple PCB's. This is a $15,000 item (just for the controls) and was from a major global manufacturer. 
 Our investigations found that there was an issue with inadequate coating on the boards and that in a high humidity situation they would very quickly fail. Tassie isn't that humid, but it's humid enough to cause the failures it seems.  
Further investigation uncovered that they had outsourced manufacturing to some unknown producer in China whereas previously they made them in their own factory. It was causing a lot of issues - we had 3 faults at the same location within a year and all required an immediate (any time, day or night) site visit and replacement. 
To cut a long story short, we are now using a different system that integrates fully with all the other gear we have. It's a direct replacement, even the holes for the mounting bolts line up. And the good news is that the new product is from a company that manufactures their boards right here in Australia (though no doubt the components would be imported but at least it's as local as they can reasonably manage to do). And it's a bit cheaper too. Thus far, we haven't had a single failure with it. :Smilie:

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## phild01

Maybe the problem with PCB's is the Chinese manufacture.  If a shortcut in quality can be taken, they will do it if nobody is watching.

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## Brian7886

Usually a burnt out board will come from a blown component, be it a resistor capacitor or diode etc. but under warranty theyll swap the whole board and request the old one back for investagative purposes

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## Smurf

I can't remember exactly what had failed, but with the Panasonic board I repaired a decade or so ago it was just one component that had failed. Everything was working except that it wasn't activating the relay to turn the compressor on. 
After a bit of fault finding on the PCB I just replaced the faulty component for a few $.  
But in a commercial servicing situation where labour costs money, fault finding PCB's in general (not just air-con but with everything) is a dying activity at least in Australia. The trend is very much toward just replacing whole boards. Part of that comes down to labour costs but part is also due to technology - it's straightforward to repair something that's fairly old but you need a lot more than test equipment and a soldering iron to replace modern surface mount components where everything is tiny - they're impractical to repair in practice (could be done in theory, but not worth the cost of being set up to do it). 
At work we still fault find and fix some old gear (after swapping the board to get it running), but anything newer just gets either thrown out or sent back to the manufacturer for repair (and in many cases the manufacturer just throws it out anyway and supplies a new one).  
We've gone from 100% "in house" repairs circa 1990 (and still around two thirds in the year 2000) to less than 15% today. By the end of this decade I doubt that we'll be doing any board repairs in our own workshops at all. 
It's the same with everything. Eg there was a substantial industry repairing VCR's 30 years ago, if it broke then repair was the normal course of action (and early VCR's broke down quite often), but nobody really bothers getting their DVD player fixed today. If it breaks then either it's a warranty replacement or just throw it out and buy a new one.

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## Uncle Bob

> It's the same with everything. Eg there was a substantial industry repairing VCR's 30 years ago, if it broke then repair was the normal course of action (and early VCR's broke down quite often), but nobody really bothers getting their DVD player fixed today. If it breaks then either it's a warranty replacement or just throw it out and buy a new one.

  Yes unfortunately we've become a wasteful society and well trained, under paid electronic technicians are a dying breed these days.

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## JB1

That's because it's cheaper to replace it or the repair cost is close to the replacement.  And then, there's no guarantee it will last a long time after it's fixed. 
I would say if air conds were easy to install/replace yourself, many people would just buy new ones if out of warranty. 
Sent from my Nexus 5 using Tapatalk

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