Potterton Puma 80

[henleychap]

Hi

This is my first post so please go easy on me!

I've got a Potterton Puma 80 which has been working fine since I moved in about 6 months ago.

Now a fault has started and I can't get my head round it!

The Pilot light os on permanently and if I turn a hot water tap on the boiler fires into life and heats the water.

However if I set the central heating to constant or on timed (ON) and have the thermostat turn up it doesn't fire up.

Now I checked the CH pressure and it was a little low, so have just pressured the system back to 1.5BAR however it still doesn't fire into life.

Based on the fact it's working for water I'm guessing this is a electrical or valve issue.

Anyone know how to fix this?

 

[45yearsagasman]

Make absolutely sure that you have no hot taps left partially on or dripping even the smallest amount.

 

[Agile]

When you select heating from cold, the boilers should fire up for a few seconds to heat up the boiler if the pump is failed or for about 30 seconds if the pump is working.

Only then will the hot boiler give the diverter a chance to move and that can take a few minutes.

As said if hot tap leaking then it will never heat the rads!

Tony

 

[Gasguru]

Look at the circuit board....bound to loads of broken joints.

 

[Foobix]

The first thing to check would be that the boiler is getting a live feed from the external controls.
If the boiler fires initially then shuts down it will be the wax capsule in the diverter valve.

 

[henleychap]

Like I said it's working perfectly for water which is why I don't understand what's wrong with it.

There had been a leaking tap for ages but it never leaked enough to fire the boiler up. Also I replaced the taps yesterday so there are no leaks anymore.

Seems to me like it might be electrical, where do I start in testing that?

 

[45yearsagasman]

It depends on what controls are connected to the boiler.Check that the timer and the room stat are signalling the boiler to fire.If you have the Manual then a wiring diagram is in there.Best use a multi meter and be careful.

 

[Agile]

Leaking hot taps prevent the diverter moving to the heating position.

Have you actually tested it since?

You did not answer my simple question about they boiler firing up.

We cannot help you unless you give us the information.

Tony

 

[bengasman]

Could be:
roomstat
timer
pcb
diverter
dhw drip/leak
to name but a few.
Getting a pro out who knows this particular boiler will be cheaper and quicker than diy.

 

[henleychap]

Agile - The pilot is always on, the boiler only fires when a hot water tap is turned on. Turning the heating to constant, or letting it click to being on via the clock doesn't do anything. thermostat makes click noise at say 18degrees but doesn't cause anything to happen on boiler.

It feels to me like its not getting the signal to fire up!

 

[poolebybirth]

sounds like non power to boiler in CH mode - need to check with a multimeter! whatis CH set to on boiler as well (has it been adjusted)?