Help Halstead ace over heat cut out?

[dunk]

Hi, I'm gas safe registered.

I went to look at a friends Halstead ace boiler that keeps locking out when there is a high demand on the boiler when on central heating and hot water.
I was thinking it could be the overheat thermostat but I'm not sure.

 

[gasmarc]

if it is locking out is it over heating

 

[dunk]

I think it might be because when I felt the flow pipe with the overheat stat on it, it was scolding. In the instructions it says it could be the overheat stat but they are pretty vague. Any help would be very appreciated.

 

[cjg]

try the diverter valve, pipe blockage.and pump. hope that helps,

 

[dunk]

Thanks for replying, I didn't say that everything seems to be working. The heating and hot water both work but when the heating is on and upto temperature and then the hot water is turned on it locks out. So I think that rules out the pump, diverter valve and a blockage, but I might be wrong. I'm quite new to fault finding but I am trying to build up more experience.

 

[cjg]

sh't in diverter-ch works fine. change over , diverter not changing over? worth alook

 

[RoryD]

I think it might be because when I felt the flow pipe with the overheat stat on it, it was scolding. In the instructions it says it could be the overheat stat but they are pretty vague. Any help would be very appreciated.

should be about 11 degree difference between flow / return, try to check temp, I use my Telegan sprint, try n improvise if u ain't got one. Anyway if the return is over cool then there is a blockage. Check resistance on the thermistors about 19 Kohms at degrees. Pumps can be an issue where overheating is concerned

 

[Reg Man]

Is the air relief valve on the top on the heat exchanger working efficiently. This boiler has a reputation for overheating if air gets trapped in thetop of the heat exchanger. Check the venturi's to see if they have started to melt down, a sure sign.

 

[dunk]

Thank you for all your advise I will check everything you have said. I called Halstead tec help today and they said it could be the diverter valve not changing over fully from CH to DMH and check the resistance on the thermisters.

 

[cjg]

Thank you for all your advise I will check everything you have said. I called Halstead tec help today and they said it could be the diverter valve not changing over fully from CH to DMH and check the resistance on the thermisters.

mmmmmmmmmmmmm, diverter not changing over mmmmmmmmmmmmmm! lol