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11th March 2006, 03:42 PM
#1
Automated Home Lurker
netaheat 80E on/off on/off
I have a Potterton Netaheat 80E. As far as I understand the beast it is a gravity system and has been serviced by a fully qualified Corgi gas engineer. I am happy with everything that he has done and that is not where the problem lies.
Everything was working fine until the pump failed and this was replaced. In order to do this he had to drain the system as the shut-off valves either side of the pump could not be undone – so he replaced the pump and 2 new shut-off valves.
Water turned back on and system re-filled – radiators got hot and plenty of hot water from taps.
That’s when the problem became apparent.
The boiler starts up and after the initial burn [15 mins] it shuts down and then starts again after a minute or so – then goes off – then starts again and burns for a minute or so then shuts down and then starts and then shuts down etc etc. It then just recycles like this.
We have now changed the room thermostat and the tank thermostat. I am told everything else is working just fine but neither he, nor I, can understand why it has started to do this.
He is suggesting that the PCB be changed but I don’t want to continue to change everything piece by piece if someone has either experienced this and knows what the problem is or actually knows how to cure the problem.
I hope I have given enough information – obviously the boiler is 15 years old but everything was fine until we changed the pump and drained the system – all suggestions gladly received to help excessive head-scratching currently going on.
Thanks everyone.
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11th March 2006, 08:55 PM
#2
Moderator
Re: netaheat 80E on/off on/off
does the boiler do this on water only?
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11th March 2006, 08:59 PM
#3
Automated Home Lurker
Re: netaheat 80E on/off on/off
No. It does it with CH running as well as water.
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11th March 2006, 09:04 PM
#4
Moderator
Re: netaheat 80E on/off on/off
If it only does it on water and heating,I would say it's not the board,I would have another look at the room stat.did your old one have a neutral,or just live in live out,have you replaced it with one that needs a neutral?
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11th March 2006, 09:10 PM
#5
Automated Home Lurker
Re: netaheat 80E on/off on/off
Replaced with up to date version of same stat with same wire connections
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11th March 2006, 10:48 PM
#6
Moderator
Re: netaheat 80E on/off on/off
are the pump valves fully open?
is the pump on the right way round?
what speed is the pump on?(put it on 2)
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12th March 2006, 12:00 PM
#7
Automated Home Lurker
Re: netaheat 80E on/off on/off
Firstly, thanks for your help.
valves fully open and pump is right way around
was set on 3 - have now set it to 2 and will monitor - old pump was set on 3 so did same thing with new one.
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13th March 2006, 01:48 PM
#8
Automated Home Lurker
Re: netaheat 80E on/off on/off
Problem still there. Boiler seems to be noisy - is this related to the draining of the system and trapped air. Could this be contributing to the problem?
The strange thing is that all radiators are getting hot and the hot water tank is providing plenty of hot tap water.
Adjusting the stats will also turn boiler on/off according to adjustment up or down.
I am confused!!! to say the least :cry:
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14th March 2006, 04:43 AM
#9
Automated Home Lurker
Re: netaheat 80E on/off on/off
You say the bolier is a gravity system but if it uses a pump what pressure is the system running at. Do you have a pressure change over value between hot water and radiators or is in motorised? If its a pressure operated type it could be the valve is not getting fully opened due to low pressure. Try running your system at a slightly higher pressure.
It does sound like your circulation around the heat exchanger is being restricted and going out on over temperature.
I had the same problem with my Potterton boiler and the above seemed to cure it. Hope this is of some help.
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23rd March 2006, 12:13 AM
#10
Automated Home Lurker
Re: netaheat 80E on/off on/off
If the heating didn't work I'd have said it was an air lock or a blockage somewhere.
As it works I'd look at the burner pressure. If it's too high it would cause the boiler to cycle as you describe.
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