Keston C36 Combi problem

[vinnychase]

popped round to look at a keston c36 combi.

When running the hot water it runs for between 10 seconds and 1 minute. then the burner goes out for about 30 seconds. water obviously runs cold. boiler fires up same thing happens over and over again.

It appers on CH the boiler cuts out after 5 mins, off for a minute, then back on etc.

on both HW and CH the temperature shown on the boiler display gradually increases first time cuts out at 30 deg then rises each time gradually up to 50 deg.

Im going back tomorrow, at the moment im thinking that the heat exchanger is partially blocked? any suggestions please??

 

[vinnychase]

am i on the right track? is it more likely to be this side of things/ blockage stroke air? or on the electric side?

 

[vinnychase]

took the heat exchanger out and got a few bits out of it. and cleaned the filter. works perfectly at the moment. couldn't see a boiler drain point, which was a bit rubbish!!

 

[vinnychase]

just got a phone call, boiler has gone back to cutting out. DAM!!! any suggestions would be greatly appriciated, thanks!!

 

[Agile]

Did you inspect the pump for blockages in the eye?

Or slow running? ( Finger test ! )

Tony

 

[vinnychase]

yes i opened the front screw on the pump and water came out.

no i did not finger test the pump. please give me a brief desciption. i guess you mean feel the thing. and does it seem to be circukating at correct speed.

 

[Agile]

yes i opened the front screw on the pump and water came out.

The "eye" of the pump is in the centre of the impeller!

You have to drain boiler and remove pump head to inspect it and see if there is any dirt as that greatly restricts the pumping effect.

At the same time do the "finger test" to ensure the pump is delivering the correct torque.

Better you register for the Combustion Chamber and ask in there. Also join ARGI as you can also ask there too.

Tony

 

[vinnychase]

thanks tony, i will take the pump head off, but you suspect the problem will be linked to a restriction somewhere then?

 

[Agile]

I expect the flow is restricted and the boiler is heating to the set flow temperature and turning off.

Tony

 

[vinnychase]

ok thanks i'll let you know how i get on!

 

[vinnychase]

pump seemed fine. DHW was working fine while i was there (always the bloody way!) but over this weekend its stopped working again. i have checked every time that the pressure is correct.

searched keston problems on here, and i see they often dont get a response im guessing no one likes working on them!!

 

[gaspro1981]

on the keston c36 there is a notorious problem with ignition pcb mounted on the gas valve it can cause all manner of faults just a thought but keep this in mind

 

[vinnychase]

thanks,

anyway of testing this?