Potterton Puma 80 boiler cut out

[joffa]

When the heating is switched on and I run the hot water the bolier cuts out when the hot tap is turned off. The boiler doesn't cut out if i use the hot water if the heating is not on.

Thanks

 

[ChrisR]

Do a search on "puma flow switch". It's sticking on.

 

[joffa]

Hi

I replaced this last year and had it apart this weekend, descaled lubricated and replaced. I thought if it was sticking it would do so whether the heating was on or off.

Thanks

 

[ChrisR]

Easy to check - the red light on the pcb stays on when the tap goes off.

 

[joffa]

So the red light stays on when the tap is off if the flow valve is sticking?

Thanks

 

[joffa]

The red light doesnt stay on when the water is turned off. After about 40 seconds ther is a small @dink' sound and the boiler turns of, pilot goes out. As i said before, thid only happens if the heating is on at the same time, not when the heating is off.

 

[joffa]

Anyone have any ideas?

Thanks

joffa

 

[Agile]

Joffe, where do you live? Can you add your location to your profile so it shows up.

When was the boiler last serviced?

Does the CH work as expected?

Have you measured the resistance of the two sensors with the boiler completely cold?

Tony

 

[joffa]

I am in Biggin Hill, Kent.

The boiler was serviced last year when I had a new pressure vessel fitted.

Yes, CH heating seems to work OK.

Not sure what you mean by the 2 sensors?

Thanks

joffa

 

[Agile]

Replacing the EXV on a Puma normally needs the boiler to be taken off the wall! In most cases its not even necessary as the problem is mostly a blocked communication pipe.

To repair boilers a certain degree of technical knowledge is required.

The sensors control the temperature inside the boiler. They are NTC resistors and a resistance measurement with the boiler cold would indicate if one is faulty.

You may need to call a competent boiler engineer!

I was asking where you live because some areas have hard water although that is not normally a problem with the puma but it has to be taken into account as a posibility.

Much of Kent is on chalk although we dont see many hard water problems from there so the water may be sourced from non chalk areas.

Tony

 

[joffa]

The guy fitted an external pressure vessel, as this was the cheaper option and I was thinking of getting a new boiler anyway. I was hoping for a qhick fix in this instance, this may not be the case though.

Thanks