Potterton combi80 running too hot.

[Kentbloke]

Hi everyone,i have acombi80 that is proberly about 8-9yrs old.It has always seemed to run too hot,rads too hot to touch.Had a guy look at it last winter,(not my favourite person,very arrogant and cocky)he fitted a new modulation control board,still the same.He then deceided it needed a new thermister,and came back and fitted that,still the same.At this point i think i might have said the wrong thing,(are you sure you know what you are doing?)He then left.Boiler running to hot still,has now started to not cut the burners off when water in rads gets to very very hot,so pressure goes up above 3 bar.Overheat thermostat hasn't locked down boiler yet,so can only assume it does cut burners off just far too late.Hot water side of boiler fine.
Any advise greatly recieved,don't want to call another chap in untill i have your expert appinions.

 

[gas_man_gaz]

does it fire up without demand? could be a stuck switch, even had it with some halstead boilers where the stuffing box leaks into the switch and keeps the boiler on!

not the best idea to sugest that ya gas man dnt no wat he's doin, think id of took ya money n gone n all!

 

[Agile]

Without being in front of your boiler and without knowing exactly what temperature you boiler gets to its difficult for me to huess whats wrong.

It sounds as if the expansion vessel needs attention!

You have suffered from a parts changer who has no diagnostic skills. I would noty wish to be paying someone who just changed parts which were not needed. You could have done that yourself!

Tony

 

[Rob]

Am i right in saying you dont have a temp control for your rads on the boiler. in which case they will get hot!

You can adjust the power input to the boiler, most just leave it on max, but this will mean they will still probably get hot just a bit slower!


I cant really see that there is any fault. Fit TRV's to control rad temp and a roomstat to control ambient temperature.

The expansion vessel probably needs recharging to solve the pressure problem

 

[Agile]

I always adjust the power input!

If its the Puma with no temperature control then the temp is set for about 82° and could have drifted higher as components age.

The power level will help the problem or slow it down.

The gas valve may well be seriously out of adjustment if its not modulating down. That needs a CIORGI !

Tony

 

[ChrisR]

That needs a CIORGI !

Can they see better with two I's?

 

[gas_man_gaz]

That needs a CIORGI !

Can they see better with two I's?

 

[Kentbloke]

Hi guys,thanks for all the info.I believe it's almost the same as the Puma,just 1 model older.There is no control on the front for temperature,it's preset at factory.I assume the components that control the 82degrees are at fault.But wouldn't this be the thermister?Or is there some other little whatsit in there somewhere?The small black pot on the p.c.b. ajusts the flame size up/down,does that mean the modulating valve works?I thought most corgi,s had 2 eyes,all the Queens one,s seem too?Thanks again for all your efforts,any more advise greatly received.