Potterton Puma 80 problems

[Harrowslayer]

Any help on the following would be much appreciated!!

When i turn on the hot water tap the boiler fires up and operates normally, however when i turn of the tap the boiler continues to run and the only way to stop it is to turn of the power!!

Is this due to a faulty PCB or something else??

 

[petit_pablo]

Hw flow switch is sticking on after a demand. Will cause the boiler to overheat too

 

[Harrowslayer]

is it easy to replace the flow switch and can anyone tell me where it's located??

 

[GodKnows]

Simple job, get a recommended RGI to safely replace the DHW flow switch fella.... Sooner rather than later as well

 

[Agile]

You have been told that its sticking!

Merely replacing the switch is unlikely to solve the problem.

It needs to be examined by someone who is familiar with the boiler and can identify exactly whats causing the problem.

If you must try to repair it yourself then you would need the hydraulic unit and switch and replace the whole assembly.

I usually manage to repair them without replacing.

Tony

 

[ChrisR]

The hydraulic part is also called a "switch" by Baxi/Potterton and that's probably what pp meant.

Poster - do a search - plenty here.

 

[poolebybirth]

If the flow switch is stuck, when you turn your hw tap off, you may get htg on, depending on whtether the diverter valve is also stuck or not!!

 

[petit_pablo]

If the flow switch is stuck, when you turn your hw tap off, you may get htg on, depending on whtether the diverter valve is also stuck or not!!

Not on a puma, the wax capsule being heated will keep water circulating through boiler

 

[Harrowslayer]

Thanks for the advice everyone, much appreciated. I would still appreciate any comments on where the switch is located.

 

[petit_pablo]

Thanks for the advice everyone, much appreciated. I would still appreciate any comments on where the switch is located.

Sorry, drop down pcb housing(remember to turn off power 1st) and its the round brass bit next to the gas valve at the bottom left. It will have a hexagonal shaped bit protruding and a microswitch on the end.

Edit: Looks like this

 

[Agile]

If the flow switch is stuck, when you turn your hw tap off, you may get htg on, depending on whtether the diverter valve is also stuck or not!!

Not on a puma, the wax capsule being heated will keep water circulating through boiler

As long as the DHW flow ceases, the diverter valve will move to the CH position as soon as the front part warms up which is about 20 sec on a new one and 60 or more on an old one.

Tony

 

[Gas2Air]

Tony. Wax capsule. You haven't timed them have you?

Petit_pablo where abouts in lincs are you from?

 

[Agile]

Tony. Wax capsule. You haven't timed them have you?

There is little point because the response time is so variable and depends on several factors.

So its anything between about 20 secs in a few rare cases with a new diverter valve and about 3 minutes or longer with an old and dirty diverter and a long time if there is still some slight DHW flow leakage.

It also varies according to the selected CH temperature!

Tony