# Forum Home Renovation Heating & Cooling  Brivis ducted central heating issue

## renofun

G'day, 
Have a Brivis HE 20i ducted central heating unit with:
- Wall controller: Networker V1  
- N-G1/lo heting module 
The wall controller is working and shows Heater, Fan and time. When operating with the Fan only, it works fine.  
When turn on the heater in 'Manual" operation, the wall controller is automatally on and off but no hot air coming into the house.  
Strange enough, the heating unit can run differently each time. :Confused:  
Sometime, we cannot turn on the wall controller even it displays time (but no Heater/Fan). The NG1 shows "Searching". 
Sometime, we can turn on the wall controller but it off again after a few second. The NG1 shows "MPS_OFFnG" | "Searching". 
Sometime, we can turn the wall controller, the heating unit seems working for a while but will off again later. The NG1 shows "Pre_Purge", etc. We can see the fire ignited but off within a coupe of seconds, fan runs, the fire ignited but off again ...  
Any ideas what wrong with the unit and how we can fix it? 
Also, where is the Thermocouple for this HE 20i unit (very similar like this one)?   
Does the wall controller have a reset function/button?  
TIA.

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## president_ltd

> Strange enough, the heating unit can run differently each time.
>  Sometime, we cannot turn on the wall controller even it displays time (but no Heater/Fan). The NG1 shows "Searching".
>  Sometime, we can turn on the wall controller but it off again after a few second. The NG1 shows "MPS_OFFnG" | "Searching".

  for starters, i'd check the wiring between the internal panel (Networker) & the outside unit.
its a wire-wire connection, maybe its come loose?
 (my guess is that is what 'searching' is all about) 
would also explain why its different results.
maybe a rodent has chewed through or exposed the wires somewhere?
or its sitting in a puddle of water?   

> Sometime, we can turn the wall controller, the heating unit seems working for a while but will off again later. The NG1 shows "Pre_Purge", etc. We can see the fire ignited but off within a coupe of seconds, fan runs, the fire ignited but off again ...

  does your Networker have the ability to show error messages?
(have a Networker v3 here, it shows error codes scrolling on it with a spanner on the LCD if there is a problem)   

> Also, where is the Thermocouple for this HE 20i unit (very similar like this one)?

  there are multiple thermocouples inside a HExx.  about 3 from memory.
they serve different purposes.   

> Does the wall controller have a reset function/button?

  no. 
there is the 'service manual' for Brivis HExx posted in the library here. you may want to see if there is anything useful/helpful in that...

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## renofun

Thanks a lot for the prompt reply. Will check the the wiring.   

> or its sitting in a puddle of water?

  The outside unit is underneth the house but it seems to me it's setting on a dry (but dust) ground.   

> does your Networker have the ability to show error messages?

  No. Cannot find any error messages. Please correct me if I am wrong.   

> there are multiple thermocouples inside a HExx.  about 3 from memory.

  Are they in side the "burner assembly" in the following diagram? I think it is the box labeled with the "natural gas only" in the picture above.

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## chrisp

> Are they in side the "burner assembly" in the following diagram?

  I think they are one of the two modules you can just see in the bottom left side of the photo of the opened heater. 
In any case, it is really just a matter of noting where they are connected on the electronic modules (from the circuit diagram in the post above) and following the wire down to the sensor.

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## renofun

Thanks, Chrisp. 
I am not sure if the thermocouple is same as "flame sensor"? Which wire from the diagram above I should use to find the thermocouples? Is it possible the issue caused by the thermocouple?

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## chrisp

> I am not sure if the thermocouple is same as "flame sensor"? Which wire from the diagram above I should use to find the thermocouples? Is it possible the issue caused by the thermocouple?

  If your unit is igniting (i.e. you see a flame), but it is shutting down soon after, it would indicate that the unit isn't detecting that the gas has ignited.  The circuit diagram shows two flame sensors.  I'm not sure what type of sensor theses are.  The term "thermocouple" is used very loosely in the heating industry to refer to many different types of sensors.  I'd be having a look at the 'main flame sensor'.  It might be a temperature sensor, or it might just simply be a metal probe that senses the presence of the flame (flame is conductive). 
It might be easiest to replace the flame sensor and see if the unit comes good.

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## president_ltd

> I am not sure if the thermocouple is same as "flame sensor"? Which wire from the diagram above I should use to find the thermocouples? Is it possible the issue caused by the thermocouple?

  at least one of the "flame sensors" is intended to be about 1 metre 'inside' the main output duct.
its not critical for system operation.  (i know this from experience.)
in the diagram this is marked the AFRO sensor. 
there are multiple temperature sensors - the "supply air thermistor", the "flame sensor", "backup flame sensor" & "AFRO sensor".
not sure what the AFRO sensor is but i think its likely a thermocouple or thermistor.

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## renofun

> It might be easiest to replace the flame sensor and see if the unit comes good.

  Check the part that goes into the "burner assembly". It's a part with three ends. Two for ignitors and one for the flame sensor. There is a label saying NORTON, 22.5V, 15002, 9930, and Model 451. Just wondering where I can by the part.

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## chrisp

Maybe, have a look through this web site and see if you can find the part: Brivis - Heating - Appliance Spare Parts - Northern Gas and Electric - Melbourne 
I think some other forum members have managed to buy parts from the regular plumbing outlets (Reeces etc.).

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## ozheat

No thermocouples in the brivis HE20i, thermocouples are only a pilot flame flame faile device and you have no pilot light.
Brivis servicing of these HE units is a closed shop and only done by brivis techs.
I am not a brivis tech but I have been around these unit to know how the work.
You might be able to dignose by a process of elimanation. 
1-.  TESTING IF YOUR MPS CONTROLLER IS FAULTY. 
We are going to see if the thermostat wire is faulty. 
Disconnect power to the heating unit. 
remove the themostat from the wall by pulling the bottom of the thermostat from the baseplate.  
Remove the baseplate from the wall by removing the 2 screws.
Disconnect the 2 wires that go to the terminals on the baseplate making sure that you don't loose the wire down the wall(tape some string to the wire).
Now take the thermostat to the heater.
You will need a short piece of figure 8 wire, you can probally use the exisiting figure 8 alreaddy installed as the should be enough slack to cut a 6" piece off and still be able to reconnect the wire later.
The thermostat wire is the thin figure 8 wire that comes out of the heater.  It is also the wire that enters the control box at the end where you see the blue square brivis logo.
Pull that panel out by pulling the end where the wire enters.
You will see the 2 wires go to a terminal strip, with a small flat bladed screwdriver remove the 2 wires or if you are going to cut the wire and use a 6" of the existing wire just leave it.
Strip the wire and connect the 2 wires to the controller base, there is no polarity to the wires so either wires will do and there is no dangerous voltages in these wires.
Replace controller on the controller base by placing top on first then clicking bottom on.
Turn heater back on, you should see your normal heater display although clock & program will be reset but don't worry about that now.
Turn controller to manual heat and then test heater.
If this doesn't fix your problem come back and tell me then I can go through different steps to go through as this is taking me a lot of time to type out  :Smilie:

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## ozheat

AFRO sensor, don't know full acroym but it is  .... Flame Roll Out sensor and I think it is an optical sensor, it detects if there is too much gas or air going to the burners causing liftoff of the flame from the burners.

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## ozheat

Hmmmm, stupid me.
I wont be the controller wires as you have power going to the networker.
Scrap step 1.....
seems I'll have to type out  the next step..... stand by.

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## ozheat

I should have read your error messages beter.
"Sometime, we cannot turn on the wall controller even it displays time (but no Heater/Fan). The NG1 shows "Searching". 
Sometime, we can turn on the wall controller but it off again after a few second. The NG1 shows "MPS_OFFnG" | "Searching". 
Sometime, we can turn the wall controller, the heating unit seems working for a while but will off again later. The NG1 shows "Pre_Purge" 
These aren't controller faults they show ignition failure.
I would firstly check the silicon hose that goes from the combustion fan to the gas valve, these perish/crack due to the heat and age and then start to leak.
If you look at the picture you posted and turn it 90 degrees so that the "natural gas  only" sticker is the right way up.  The black hose is on the vertical part of the combustion fan that looks like "9" and then connects to the gas valve
Check the ends of the hose for any signs of cracking, if they are probbaly leaking causing the "pre purge" fault.
You can fix them up by cutting the cracked part off and then reattaching them with new zip ties

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## renofun

> wont be the controller wires as you have power going to the networker

  Correct. The wires are fine.

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## renofun

> at least one of the "flame sensors" is intended to be about 1 metre 'inside' the main output duct.
> its not critical for system operation.  (i know this from experience.)
> in the diagram this is marked the AFRO sensor.

   This is the answer about AFRO I found within the forum:  

> since this isn't in any manual i have, i called Brivis, they tell me that its 
> the AFRO sensor which is a safety thing that 
> apparently detects "flame in the return outlet".  i.e. if its trying to set fire 
> to the ductwork

  I actually took out the part. It does not like a thermocopule. I believe it will be melt when flame appears in the output duct. As a result, the sensor will signal the unit to stop.

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## renofun

> Check the part that goes into the "burner assembly". It's a part with three ends. Two for ignitors and one for the flame sensor. There is a label saying NORTON, 22.5V, 15002, 9930, and Model 451. Just wondering where I can by the part.

  After I took out the part, I realised that it only has two ends in the "burner assembly" and only one ignitor which has two cables and one flame sensor. Within the "burner assembly", there is another flame sensor, the backup one. 
It costs me just over $100 to get the part (the part number is B015379).

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## chrisp

> This is the answer about AFRO I found within the forum: 
> I actually took out the part. It does not like a thermocopule. I believe it will be melt when flame appears in the output duct. As a result, the sensor will signal the unit to stop.

  The is a thermistor in the outlet duct - a metre or so out from the heater.  As I recall, the heater is designed to heat the air 50 degrees above the incoming air temperature.  i.e. if the incoming air is 15 degrees, the out going air will be 65 degrees.  I think this is something to do with the 'high efficiency' design.

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## renofun

Now, I replaced the part. Turn on the gas, turn the switch on the unit. Go to the wall controller, press the On/Off button, the light is on. 
The unit starts, the flame appears and then disappears again. However, the light on the wall controller is still on, which is different from before. So, I left it on. The flame appears and diappears a couple of times. Eventually, it works!  :Woot:  
Thanks a lot for everyone's helps. You guys are great!!! :2thumbsup:  :2thumbsup:  :2thumbsup:  
This is the best forum I have ever used. Thanks!

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## chrisp

Can you post some pictures of the part (or the old part) so we know exactly what to look for? 
Well done with the repair!

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## renofun

> Can you post some pictures of the part (or the old part) so we know exactly what 
> to look for?

  No problem.

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## renofun

The issue is back again :Confused:  
Basically, the unit worked only once after the part replaced. Now, it stops working again.  
On the N-G1/lo heating module, it shows the following message repeatly:
PRE_PURGE
HSI_WARM
FLAME_PRU
SEARCHING
POSTPURGE (not always appears). 
The flame starts and then off within 2-3 seconds.   

> I would firstly check the silicon hose that goes from the combustion fan to 
> the gas valve

  Did check the black hose. It looks fine for me. 
Any ideas what is wrong?

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## chrisp

Does the flame appear (and then go out)?  If so, I'd be looking at the flame sensor again - is it located correctly?  Is the flame touching it?  Is the burner grounded (if it is a flame contact type flame sensor)?   
It might be worthwhile cleaning the ground connections (and I'm guessing the burner will be grounded somewhere too).  Also, it might be a blocked burner hole near the flame sensor.

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## renofun

Yes, the flame appears and then goes out. From what I can see the flame istouching the flame sensor.  The unit is setting on the concrete blocks on the floor, very similar withthe unit shown in the second picture above. Cannot find any cable that is connecting to the ground.

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## chrisp

> The unit is setting on the concrete blocks on the floor, very similar withthe unit shown in the second picture above. Cannot find any cable that is connecting to the ground.

  The flame sensor, if it a non-temperature sensing type, will depend upon the flame completing an electrical circuit.  If the flame is absent, the circuit is open; if the flame is present the circuit is closed.  i.e. the flame itself is part of the electrical circuit. 
Assuming the flame is okay and the probe is touching the circuit, the 'break' in the circuit might be elsewhere - such as in the cable to the sensor (unlikely as it is new) or in the return circuit via the burner.  i.e. the metal part of the burner will somehow be connected back to the control unit.  Often this is done via the metalwork rather than by wires.  It might be that the screws securing the burner to the frame are rusty and giving a poor contact in the 'ground' circuit.  (Also, if the flame is 'lifting off' the burner, it may cause problems with the flame sensor.) 
You don't need to worry about whether the unit is wired on the the dirt under the unit.  The 'ground' I refer to is the electrical ground which is usually the metalwork of the unit.

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## renofun

Tried to clean up the dirt and dust under the unit. Still not work.

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## renofun

Not sure what is happening. 
Yesterday, after I turned on the wall controller it stayed on until I switched it off. 
Today, the controller is automatically off straightaway after I turned it on.  :Mad:  :Confused:  :Mad:  
Any ideas? Help!!!

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## president_ltd

> Not sure what is happening. 
> Yesterday, after I turned on the wall controller it stayed on until I switched it off. 
> Today, the controller is automatically off straightaway after I turned it on.  
> Any ideas? Help!!!

  unless you've validated the wiring to the inside controller (networker) is fine, i'd just check that is REALLY the case.
remove the networker from inside the house (be careful to ensure the cable does not get lost inside the wall, knot it so it cannot be pulled into the wall), go under the house with the networker and connect it up much closer to the unit and see if it works from there. 
it may well be that a rat or mouse has chewed through part of the cable and its shorting the wires together every now & again.
or: that there is an exposed wire on the cable and a bit of moisture somewhere (like the rain yesterday) is causing it to short that wire. 
if this turns out to be the issue then use the existing figure-8 wire to pull through some new cable.  
i'd also check & make sure every connection is firmly connected on the various PCBs on the unit.  may be that one of them is slightly loose and some vibration causes it to malfunction in strange ways.

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## renofun

Thanks for the suggestion. Will do it. It will also make my tests much easier. Will update on it.

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## renofun

I validated the wiring to the controller by connecting it with a very short figure-8 wire. However, it makes no changes. The unit is still not working.   

> i'd also check & make sure every connection is firmly connected on the various PCBs on the unit.  may be that one of them is slightly loose and some vibration causes it to malfunction in strange ways.

   Do you mean all the Printed Circuit Boards? OMG, no sure how I can do it? I did have a look at the controller and N-G1/lo heating module but cannot see any obvious damages.  :Frown:

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## renofun

Hi all, 
Any other suggestions before doing something to the PCBs? 
It seems to me there are only two PCBs within the units, i.e. networker and N-G1/lo heating module. Am I right?

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## chrisp

> Any other suggestions before doing something to the PCBs? 
> It seems to me there are only two PCBs within the units, i.e. networker and N-G1/lo heating module. Am I right?

  Your two points in order: 
Do you have a multimeter?  If so, the first thing to check would be the 24V power supply. 
There is another module behind the panel that holds the combustion air  fan (the one you can see in the photo).  This module is troublesome as  it sits in the main air path and seems to collect fine dust in the air.   The dust eventually causes an arc over in the unit and damages it.   It  could be worthwhile having a look on it and cleaning the dust out  before it arcs over (or seeing if it already has).

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## ozheat

was going to write something about willy nilly changing parts out but will hold my tongue.....
First of all give me the status of what the heater is at right now and where the thermo is located.
Second. do you have any test equiptment such as a multimeter, monometer & aspirator?
Thirdly. don't go out changing sensors just because you can, only replace them if they are faulty!!

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## ozheat

ok, I can't wait for an answer gotta go out soon. 
I suspect that the flame sensors are working 100% and are doing their job, the HSI is working as the flame gets lit.
I doubt there will be any module that chrisp describes as this is a mk1 Hot surface ignition and just uses 24V not a spark ignition as in mk2 and later models. 
Your fault is an ignition falure. 
ignition procudure go roughly like this......
1. thermostat calls for heat
2. start combustion blower
3. pre-purge this clears combustion chamber of any gas that may be previously been there.
4. start ignition, HSI will heat up.
5. gas ignition flame established, main flame sensor has detected flame.
6. flame backup sensor detection. this tells if the flame coming out from the burner is ok.
7. pre-heat heat exchanger.
8. start main room fan. 
I think you are getting up to step 5 and failing step 6
The best way to test this is to use a multimeter on the backup flame sensor connector.

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## renofun

> Do you have a multimeter?

  Yes.

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## renofun

> I think you are getting up to step 5 and failing step 6
> The best way to test this is to use a multimeter on the backup flame sensor connector.

   It sounds right to me as when it works I can hear a bigger bang sound and then main room fan is on.  
Just wondering how I can test "the backup flame sensor connector" with a multimeter? From what I can see the backup flame sensor has one end like the flame senor shown in the part picture above. Another end is acutally on the PCB of the N-G1/lo heating module.

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## chrisp

> I doubt there will be any module that chrisp describes as this is a mk1 Hot surface ignition and just uses 24V not a spark ignition as in mk2 and later models.

  ozheat, 
I appreciate the help you are providing, but just for the record, the unit pictured is mine - and YES it is a hot surface ignition unit - and YES it does have that module that you "doubt there will be any module that chrisp describes".  If you are interested, I have posted a thread showing the repair of this non-existent module.   :Smilie:

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## renofun

> If so, the first thing to check would be the 24V power supply.

  Is the power DC or AC? Where is the power supply point I should test? I can only see the power goes into the N-G1 module.    

> There is another module behind the panel that holds the combustion air  fan (the one you can see in the photo).

  How can I access that module? Do I need to take the combustion air  fan out?

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## renofun

Yes, the unit picture is yours, Chrisp. The steps ozheat described is about right for my unit. 
However, I have no idea about the different between a hot surface ignition and a spark ignition. I believe the part picture show the ignitor.    
I really appreciate the helps all you guys are providing and am trying hard to understand and work out the issue. Thank you very much for all of you.

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## renofun

> give me the status of what the heater is at right now and where the thermo is located

  The status of the heater is still unstable but quite often it still do this:  

> On the N-G1/lo heating module, it shows the following message 
> repeatly:
> PRE_PURGE
> HSI_WARM
> IGNITING
> FLAME_PRU
> SEARCHING
> POSTPURGE (not 
> always appears).

  No sure where the thermo is. I remember you said "No thermocouples in the brivis HE20i". However, the wiring diagram picture above might give you some hits.

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## chrisp

> Yes, the unit picture is yours, Chrisp. The steps ozheat described is about right for my unit. 
> However, I have no idea about the different between a hot surface ignition and a spark ignition. I believe the part picture show the ignitor.    
> I really appreciate the helps all you guys are providing and am trying hard to understand and work out the issue. Thank you very much for all of you.

  The high efficiency unit of this vintage (the ones with "HE" in the model number) are hot-surface-ignition units.  The photo of the replacement part you posted shows this unit (the U-shaped piece of metal).  They don't use a pilot light (which uses gas all the time). 
The 24V power supply is generated on the N-G1/Hi model - this is on the rear side of the panel that hold the "Flue fan" (the fan you can see in the photo earlier in this thread).  If you remove the half-dozen (or so) screws that hold flue fan panel and the rubber tube, you can lower it and you will see the N-G1/Hi model (this is the one I wrote a thread about), and the 240V-24V transformer.  Have a look at the circuit diagram on the inside of the cover.  *Please be extremely careful here - 240Vac is present on wiring to this module - unplug the heater first.* 
The N-G1/Hi models are troublesome - I have fixed these before for friends - and all for the same reason - dust builds up inside them and it arcs the 240V over to earth.  It often blows tracks off the circuit board.  If this has happened, you could get all sorts of problems.  Regardless of whether this is your problem, I would suggest cleaning the dust out as it will be a problem eventually. 
You can also check the 24V supply at the N-G1/Lo module - there is a fuse in the 24V supply.  I'm not sure if this is AC or DC (I haven't had to check as the trouble I have had was earlier).  I have a faulty N-G1/Hi module on-hand (one I'm repairing for someone else [when I get around to it  :Rolleyes:  ] so, if you need, I can look at it to see if it does the rectification of the 24Vac to DC.  I've attached a photo where you can (just) see the fuse.  From memory (but I could be wrong) the 24V supply is labelled on the N-G1/Lo module (but the labels are molded in the plastic and can be hard to read). 
If your unit is behaving erratically and misbehaving differently at times, checking the basics like the power supply is usually a good start.  * 
Please follow whatever suggestion ozheat has, or gives.  He seems to have a lot more experience with these things than me.*  I'm an electronics design engineer so I know my way around electronics, but I haven't had to go through these units with a fine tooth comb.

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## ozheat

First of all sorry chrisp, I thought you were saying that an "ignition module" had arced over which is another common problem due to the HV atrracting dust but only in spark ignition.
Also I believe it will be 24VAC present at the terminals as it is there for zone damper motors. 
Renofun,
  " when it works I can hear a bigger bang sound and then main room fan is on" this confirms to me that your problem is in fact the combustion fan pressure tube that is either blocked or leaking.  This is why I wanted you to test the backup flame sensor's output but it is unnessasary now as your comment has confirmed it for me.
Probally leaking as it works intermittently and worked the first time after you installed the main flame sensor and tried to check the combustion fan tube dirsturbing it just enough to close the leak for a while. 
To really test if it is leaking you will reqire some soapy water, 6-7 drops of dishwashing liquid in about 250ml of water will do in a bottle.  Shake till the bubbles fill the remaining space in the bottle and use the fine bubbles around the tubing and tube connection, you may also have to pull and move the tube to expose the leak.  
Turn on the thermo(thermostat brivis calls it the networker) and during the ignition sequence when the combustion fan is in operation you will find the small bubbles enlarge at the leaking tube although the leak may be that large that it will just blow the bubbles away, at this point you have found your problem.
If there is no leak then the tube is blocked, remove the tube from the gas reulator end and blow in to the tube towards the combustion fan it should clear any blockage but DO NOT blow hard towards the regulator as you will rupture the diagphram.
The reason that the pressure in this tube is important is because this is connected to a diaphram which controls the gas pressure to the burners ensuring its air to fuel ratio, if it doesn't recieve the full combustion pressure it will not allow enough gas to the burners and hence will shudown the ignition sequence as you have found out.

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## renofun

I did the following:  
- the power connects to the N-G1/lo module is from somewhere behind the combustion fan
- the voltage on the network is ~12V DC 
- can hear a regular voice "da...da...da..." in or behind the combustion fan
- check the tube for the leaking and blocking but no issue found 
Are there any other places can cause the combustion pressure problem?

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## renofun

I took the combustion fan out. Chrisp is quite right. There are dust, even a small dead lizard behind the fan, might be also a dead scorpion. 
The following picture is one side of the fan (the black tube is connected to the bottom). As I can see the seals are pretty bad. I think they should be replaced. So, ozheat is quite right too.  
I also took out the N-G1/Hi model. At first, I just cleaned up the dust. Then, realised that there is a yellow mark outside the model. So, I opened it. Here are the pictures for the front and back of the PCB.     
In the top middle of the PCB, there is a burnt mark around the "R8". The reading for the R8 is 9440 K, I think. It's little dark just above the white IC1 at the right top corner. Do not spot anything else. 
My questions now are:
- where can I buy the seal tapes? 
- any suggestions on what I should do with the PCB?
- the very top right corner, it seems to me there are some white thermal paste(?) between the aluminium base and one of the component on the PCB. Just wondering where I can buy the paste and what it's called?

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## ozheat

Well if you are sure that the tube is not leaking or blocked there isn't too many options left you can do without a monometer.
Have you had any alterations to your gas supply line such as change or addition of appliences since the last winter season?
Are you sure that the gas isolation cock is completely open ie. the handle is paraelle to the tube?
Did you take out the combustion fan and if you did check to see that the inlet of the tube isn't blocked or obstructed?
Did you completely remove the tube?  What was the condition of the inside of the tube? 
The pressure setting of the burner is purely mechanical and does not rely on electrical controls besides turning the regulator on via a solenoid, the solenoid is working as you are getting gas as witnessed by the inital ignition of the burner.
What it does rely on is the combustion fan pressure and it is that tube which relays the combustion pressure to the regulator. 
The next thing that I would try is to cycle the ignition process while manipulating the tube compressing the ends down and seeing if a sucessful ignition occurs.
Also try pinching the tube letting the combustion fan build up speed and then letting go just before the HSI turns off hopefully this will free up the diaphgram and allow higher pressure to the burners.
There is the other side of the diaphrgram which goes to the exit side of the burner, that is the hard aluminium tube next to the silicon tube connected at the regulator but that will rarely go wrong. 
The diaphgram could be ruptured, unlikely as you have sucessely had the burners turn on and if it was it would never have reached the correct pressure.
The diaphgram could be stuck, jammed or gummed up.  Maybe a few hits on the regulator with a rubber mallet will free this up but there is only a slim chance of working. 
Bar these there isn't more that I would recommend you doing as you don't have the equiptment and knowledge to carry out and I don't want to try teach you over the internet.
If you can't fix it up with these procudures you will have to either get a new heater (yours is over 10 years old and they weren't designed to last that long) or bite the bullet and get brivis service out and he will probally replace the complete regulator which will be >$200 plus his time and service call.

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## chrisp

Your PCB is as 'clean as a whistle' - you don;t need to do anything to it.  The ones I've fixed are full of dust between the PCB and the aluminum panel, yours isn't.  I wouldn't be too concerned about the browning near R8.  It looks like R8 it runs hot but it looks fine. 
If you haven't separated the TRIAC from the aluminum panel, you don't need to worry about the 'white stuff'.  If you have separated them, then perhaps use some fresh heat-sink compound.  Have a look in the thread I did on repairing the module - I quoted a Jaycar part number for the heatsink compound (it can be purchased from most good electronics stores - which are going the way of hen's teeth these days).

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## ozheat

The seals could be a problem causing lack of pressure to the regulator, as the combustion fan side doesn't experience any high heat you could probally find some suitable weather seal at bunnings or just fill the gaps with some silicon but that will make it a bit more difficult removing the combustion fan next time.

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## renofun

Put the N-G1/Hi model back. Replace the seals that shows in the picture. Turned on the controller and it works. Can see the reading on the N-G1/lo model saying HEAT_<nn>. The heating stopped after a while even the controller is still on, I thought it might be reach the settings temporature. Turned the contoller off and put it back to the wall. 
Turned on again, the unit still works. Then the heating stopped again after a while but didn't come back again. Turned the power off and tried again. The unit is not working again and just doing what it is doing before.

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## renofun

> Have you had any alterations to your gas supply line such as change or addition of appliences since the last winter season?

  No.  

> Are you sure that the gas isolation cock is completely open ie. the handle is paraelle to the tube?

  Yes.  

> Did you take out the combustion fan and if you did check to see that the inlet of the tube isn't blocked or obstructed?

  I did take out the combustion fan. Do you mean the same tube i.e. the black one connecting to the bottom of the combustion fan? If yes, I didnot find any problem.  

> Did you completely remove the tube?  What was the condition of the inside of the tube?

  Yes, and it's in a good condition.   

> The next thing that I would try is to cycle the ignition process while manipulating the tube compressing the ends down and seeing if a sucessful ignition occurs.?

  Did it before, not working.   

> If you can't fix it up with these procudures you will have to either get a new heater (yours is over 10 years old and they weren't designed to last that long)

  Considering the price of the system, it is very expensive to run it each year if it only works for ten years.  :Frown:

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## renofun

The unit is working again. It seems to me it works quite normally. Certainly, I don't know if it will keep working.  
Two things I found:
- the networker is off sometimes even the heater is still running. 
- also, I did hear (only once) the bang sound came from somewhere behind the burner or the back of the unit. 
I think the leaking was definitely one of the issues.

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## renofun

Theheater was working fine last night. Not surprised, tried to turn it on todaybut it’s failed again. Do not understand why. It seems to me it's not only the leaking but also something else. :Mad:  :Confused:  :Mad:  Or, might somewhere else is still leaking. I can smell a bit of gas after the failure at step 6. Actually, is it possible the process is failed at steps after step 6?

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## ozheat

You should not smell any gas at all at the heater as any unburnt gas should be going out the flue during the postpurge.  This is a sign of either regulator leak or combustion chamber leak and is certainly not a safe condition.  Did you make sure your seals are in place after playing around with the HSI & flame sensors?  
Intermittent operation may be a sign of a sticky valve or diaphgram, get a rubber mallet or the butt end of a rubber handled hammer and give the regulator a whack to see if it is a sticking valve/diaphgram.

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## renofun

The gas smell happened way before I did anything to the unit. It seems to me the smell is from the combustion fan.

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## ozheat

That might be ok only if it is a slight trace of gas but the postpurge cycle should have blown the unburnt gas out the flue.

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## renofun

Where is the exchanger, is it possible a dirt exchanger could cause issue like this?

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## renofun

I did notice there are two cracks on the two small glasses inside the combustion chamber. Those glasses are just beside the flame sensors.

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## ozheat

The heat exchanger is behind the burner and consists of a few U shaped tubes where the combustion gasses heats up the air as it gets blown from the main room fan.
The only possibe thing to go wrong with the heat exchanger is if it was cracked or split and that would cause carbon monoxide to enter the home through the ducts, a deadly situation literaly as all you would feel is a slight arid smell and sleepiness.
Another possibility of your fault is if your flue or drain is blocked causing too much back pressure in the combustion chamber but that would be a constant failure not a interminant fault. 
A small crack in the inpection window is not an issue as I think there is a double layer of glass. 
Edit. Come to think about it, it could be a drain problem only if it was almost completely blocked causing a the water condensate to build up enough to block the heat exchanger tubes and then draining slowly enough to allow intermitant operation till it got filled enough to block the combustion gasses again.  Disconnect the drain at the heater and see if a heap of water comes out.

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## adsy69

HI just wondering if any one can help me out.....
i have a old brivis buffalo model number vr800a1160 
we are having a problem where the pilot is on, the fan is working but the burner will not ignite.
we have treid resetting the unit but still no luck  :Annoyed: 
any suggestions? 
thanks  :Smilie:

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## plum

That model number quoted is actually the gas valve type, which I believe is faulty, as it's  not opening up the main valve

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