# Forum Home Renovation Electrical  No hot water - electric system

## Manic

I have an outdoor Vulcan 315 litre electric hot water system that is not providing any hot water, it is attached to an off peak meter. I've tried nearly everything and it's still not working.
So far I've:
1) replaced the thermostat which was originally not working, hot water worked for a week after that, it then stopped for no obvious reason.
2) called the electricity company and they replaced the timer for the off peak meter. I'm told it now works OK and electricity will be supplied from 11pm-5am.
3) replaced the hot water element yesterday and still no hot water this morning. I tested the ohm reading of the element and it's OK. In fact the original one I pulled out was OK too! 
The meter reading hasn't changed so I assume no electricity is being supplied to the unit but not sure what to do next. 
I'm totally stumped as to what may be wrong, any ideas?  
I can't think of any reason why the cabling from the meter to the unit may be damaged, is there any simple way to test this?

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## Bedford

> The meter reading hasn't changed so I assume no electricity is being supplied to the unit but not sure what to do next. 
> I'm totally stumped as to what may be wrong, any ideas?  
> I can't think of any reason why the cabling from the meter to the unit may be damaged, is there any simple way to test this?

  There should be a fuse or circuit breaker for the HWS, make sure these are ok. 
I think it's best to get a sparkie out to check it out, he should be able to check continuity of the circuit, but may not be able to check voltage until after 11pm when it turns on. :Smilie:

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## Manic

> There should be a fuse or circuit breaker for the HWS, make sure these are ok. 
> I think it's best to get a sparkie out to check it out, he should be able to check continuity of the circuit, but may not be able to check voltage until after 11pm when it turns on.

  I checked the circuit breaker and it's definitely on. 
After switching the power off at the circuit breaker, I tested for continuity at the mains power at the HWS. There is continuity between the neutral and the earth wires but nothing from the positive (red) and neutral or earth wires. Is this normal?

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## Bedford

> I checked the circuit breaker and it's definitely on. 
> After switching the power off at the circuit breaker, I tested for continuity at the mains power at the HWS. There is continuity between the neutral and the earth wires but nothing from the positive (red) and neutral or earth wires. Is this normal?

  With the power turned off, the only continuity of the active (red) would be through the element. Was the element disconnected when you tested?, if so there would be no continuity as the switch is off and there is nothing connected at the HWS end. 
Note I am not a sparkie, it's best to wait for some of our sparkie members to help, or get a sparkie around to check it out. :Smilie:

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## chrisp

> I'm totally stumped as to what may be wrong, any ideas?

  Do you have a multimeter - and do you know how to use it safely on mains? 
If so, you could check the supply to the elements.  If the supply is there, but there is no heat then check the elements. 
(do all this at a time when the supply should be on) 
If there is no voltage at the element, then check the voltage _across_ the thermostat terminals - it should be zero if the thermostat is closed (element is 'on').  If you measure mains voltage across the thermostat and the system is cold, then you have a faulty thermostat. 
If the voltage at the element is zero and the voltage across the thermostat is zero, then you have a supply problem.  I'd suggest working back from the HWS, but I'd guess it'll be in the meter, fuse or timer. 
Please be careful and *don't do any of the above if you are unsure of how to measure mains voltages safely*.

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## mattski2008

The best way to test a hot water is to first turn the power of at the circuit breaker. then at your hot water system test firstly that there is no power at your supply terminals. then change your meter to Ohms range and test across active to neutral, if you get a reading somewhere around 18 Ohms(depending on the size of your element) your element and thermostat are ok and the problem is a supply issue. If this is the case then call for a sparky. If not put your meter across the element and check for that 18 Ohm reading. If your meter reads open circuit the problem is your element. If you get a reading across your element then test the two terminals on your thermostat which are usually marked A you are looking for a 0 ohm reading for a working thermostat. power supply issues could result from a faulty meter, relay, main switch, circuit breaker or a fault in the wiring all of which should be looked at by a licensed electrician

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## Bros

I had a similar problem with my neice HS system. The HW system checked out OK just on continuity so I hooked it up to the power circuit for a couple of hours to get hot water back. Then I reconnected it to the off peak relay and it went fine for 12 mths and the problem came back but on a long weekend so I did a continuity test of the HW system from the swboard and it was OK so I connected up the HW to the power again for a couple of hours then back to the off peak told them what to look for on the relay to see it is on and left it. That was three yrs ago. I suspect the off peak relay/controller but couldn't confirm it.

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## elkangorito

I strongly advise that you learn all you can about multimeters. They have been (& still are) responsible for many deaths & injuries within the electrical industry. Do a google search for "multimeter accidents"...the findings are shocking! 
Your multimeter should be a minimum CAT II for domestic use. CAT IV is much safer. 
As a matter of interest, the pic below shows an idiot (not a Thai) testing voltage in his Thailand home. He has connected the red lead to the Active of a GPO. He then placed his feet in wet soil & he "completed the circuit" by grasping the black lead. Not the sharpest tool in the shed but nonetheless a "tool".

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## Manic

Thank you all for your tips and words of caution. 
I called a sparky out yesterday who tested the element and mains back to the switchboard/off peak meter. They were both fine. After further troubleshooting, it turns out that the new thermostat that was replaced (one week) old had packed in! Upon closer inspection, one of the terminals on the thermostat was a dark grey while all others were silver, the continuity between it and the neutral which it should connect to was also bad. 
I replaced the thermostat yesterday and it works fine now. We had to get in to the off peak meter and override the timer in order to test it.  
The hot shower this morning was great  :Smilie:   :Biggrin:

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## Uncle Bob

Cool, all fixed. (I was thinking the ripple relay had gone crook).

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## Smurf

> Cool, all fixed. (I was thinking the ripple relay had gone crook).

  Just for the record, in Victoria it's just a timer that turns the off-peak on and off rather than a ripple control system with a relay. Same in Tasmania and, I think, SA.  
The older ones are just a mechanical disc that does one revolution per 24 hours, the newer ones are digital. They are sealed (in the same manner as a meter is sealed) so that only an authorised person can change the times. 
The older mechanical ones do break and have a habit of not working properly during a power failure (they should keep going, but often get stuck) which messes up the time (unless it's a 24 hour blackout...). The digital ones don't have this problem. 
Unrelated to the above, now would be a very good time to check the anode if the HWS is a few years old. Replacing the anode (about $50 if you DIY) will delay corrosion of the tank thus saving $ in the long run. Anodes only last a few years.

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## Manic

> Unrelated to the above, now would be a very good time to check the anode if the HWS is a few years old. Replacing the anode (about $50 if you DIY) will delay corrosion of the tank thus saving $ in the long run. Anodes only last a few years.

  Good point, I learnt about this while reading up on troubleshooting. Our system is only 1.5 years old so not ready for a replacement yet. Will do so in another couple of years. 
hot water still going strong for two whole days   :Biggrin:

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