Halstead AceHigh Combi Boiler not Heating Water

[gra555]

Hi All, After a bit of advice if possible, we have a Halstead Acehigh Combi Boiler fitted, its around 6 years old, we have had an issue in the past where when switching Hot water or Heating on nothing would happen, it would not fire up, we had an Engineer out and he replaced the PCB, a week later same fault so he came out and replaced the Microchip on the PCB saying it had moisture in it. Now 1 Month later same issue - no hot Water, no Heating, when you switch it on nothing happens, it simply wont fire up, if you leave it switched on it will come on eventually when it feels like in its own time. Yesterday i figured out a way of getting it to fire up everytime, if i switch it on and it doesnt fire up, i take the front cover of the Boiler and slightly turn the Pressure Release Valve, straight away it fires up everytime, with this information i was hoping someone would have an idea of what may be the issue before i go and buy a new Boiler! could it be the PSV? or another PCB issue? or something totally different, i have no knowledge of Boiler systems so completly in the dark. Many thanks in advance.

 

[bambibasher]

you should not be taking the cover off.
get a registered gas man out to clean out the venturis and to check the A.p.s switch. first

 

[mickyg]

you should not be taking the cover off.

i think he just means the outer cover, keep your pants on.

 

[mickyg]

have to say, sounds like a peculiar problem... does the pump run when a demand is present? could be the pump flow switch, i think these have one, haven't seen on in ages. I can only imagine that by opening the prv you are in someway simulating some flow and temporarily operating the pump flow switch...or it could be a complete red herring!
venturi problems are common on these as above, but thats an rgi job.

 

[gra555]

Yes , i just mean the outer white cover, i opened the control panel and behind this is the PRV, when i slightly turn the red plastic cap at the end the boiler fires up straight away. Once its fired up it works perfectly until you switch it off, i then have to turn the PRV again to fire it up.

 

[gra555]

Thanks for the reply MickyG - the pump doesnt always run when a demand is placed, i turn the switch on the control panel for hot water or heating and 70% of the time nothing happens, you dont hear anything and nothing fires up, then randomly 30% of the time when you switch it on it will work first time, and the loud fire up can be heard as the burners light up.

 

[mickyg]

i can't find a manual for this boiler, so i'm just gonna guess its got a pump flow switch operated by a diaphragm and this is not opening properly, your turning the prv is giving it a "boost". I may be wrong, someone will hopefully confirm. oh and btw, you will soon need a new prv, no doubt, keep opening it will end up in it passing and dripping outside.

 

[Agile]

If the pump is running but it does not fire up until the PRV is touched then the system flow switch is not operating reliabilibly.

Thats either dirt in the pump impeller, a weak pump or a dirty flow switch housing. In theory the flow switch diaphragm might be damaged but I have never seen that problem.

Tony

 

[gra555]

Thanks for the replies on this, i have managed to find a manual -

http://www.hgdheating.co.uk/downloads/SEBoiler/AceAceHigh Manual.pdf

On Page 29 it shows the Flow Switch but it also shows various other flow switches e.g Primary/Flow switch, DHW Flow switch, also the large metalic Flow Switch near the PRV, Would it be the large metalic Flow switch thats likley to be faulty, the one with all the pipes going to it? is there an easy way to test or tell if this is faulty?

 

[mickyg]

primary flow switch

 

[gra555]

Thanks for the replies on this, just to let you know it looks like you may have hit the nail on the head, yesterday i removed the Flow switch and exposed the pin that goes up and down to push the switch on/off, i then turned the hot water on and watched the pin rise and straight away the bolier fired up, after about 3 seconds it then switched off and the pin lowered, i take it the boiler went off because it detected the flow switch was removed, i then re-attached the flow switch and put it all back together, switched the heating on and right away it fired up again. Would this confirm to you guys that it is the flow switch? i know its difficult to say without seeing it but do you still think it sounds flow switch related? if so are these things cheap to buy? thanks in advance.