halstead ace high heating problem

[grame]

Hello all,
I have a Halstead Ace High which has developed a problem. The domestic water works fine but the central heating will not run at all.
I thought that the thermistor may have been faulty but it checks out ok the resistance is around 12-15 ohms when it was warm and I checked the resistance to the body and it was 3M ohms which i presume means that it is ok. I drained the boiler and removed the micro switches and unscrewed the end off the `group set` ( opposite end to the diaphragm housing.
I removed the valve and spring and then checked that the other end of the valve could move by pressing it backwards and forwards. This eased off and I built it back up again . The bolier fired up and everything appeared ok.
However three days later the heating stopped again, I tried the same routine but it will not fire up.
However if I disconnect the CH thermister the boiler fires upp foir about 15 seconds and then shuts down.
It seems as if the boiler is not seeing a demand from the heating system, I do not have a thermostat just thermostatic rad valves. System has been installed for 7 years with no problem, I wondered if it needed a flush out as I last did it 2 years ago.
Can anybody help? several cold children and wife say no more.

 

[fireblade]

I have been to halsteads and it was the time clock put a link wire in the twoo black wires on the timeclock see if that works

 

[grame]

thanks for answering but I am a little confused as the timeclock has only the two red wires and two orange ones,where do I fit the link?
Regards
very cold

 

[Billy Bob Bob]

you need a multi meter,or what does it say on the back of the clock

 

[fireblade]

Its the two orange wires on the timeclock

 

[grame]

thanks guys,
rather than risk anything I will leave till tomorrow when I can make up a link with spades etc.
When I listen close to the clock it does appear to be making some very strange buzzing noises, unlike the usual faint ticking it normally does.
As I said before the domestic water is fine , the thermistors check out and the flow switches both operate correctly and the pins are moving the full travel so I suppose thinking logically it has to be something purely related to the heating control, either the clock or the PCB.
To think I used to have a Villant and I replaced it with a Halstead! Having said that it has been great for 7 years so I shouldn`t moan really.
By the way I appreciate the help and I also dont mess about with the gas side at all ..I do use the experts for that it is just that the guy I usually use is skiing, plumbers must get far too much money..haha only joking

 

[fireblade]

No problem if its the time clock it would be the contacts inside the timeclock sounds like it will be if the hot water is ok then it sounds like no call for heat let us know how you get on tommorow cheers kev

 

[grame]

Panic over, it was the clock so I have ordered another one. When I put the link in it fired up straight away,but only on continuous as I think the timer is kaput. Having said that it started up on the timer this morning so it looks like an intermittent fault. I will change the clock anyway.
Once again thanks very much for the help , I am almost popular again with the family.
Best regards
Graeme

 

[fireblade]

No problem