POTTERTON PUMA 80E - WATER FROM AIR VENT & LOCK OUT

[Graham81]

Hi All

I have a Potterton Puma that is sick. When demand is made for either hot water or central airing the flames kicks in, the pump starts but then you can almost hear the pressure build before the boiler locks out & a small amount of water/steam comes out of the air vent at the very top. In fact the pipe has corroded some what so I guess this may have been happening for a while.

Any sugestions to what the possible fault could be here?

Many Thanks

 

[Graham81]

I have managed to get the boiler working(ish) by turning the central heating control AT the boiler itself down. However the boiler is running with a noise I can only describe as "fluttering" like the water is struggling to flow through it.

Any ideas?

 

[Agile]

System pressure?

Does the gauge increase when you add water?

These boilers are slightly unusual in how they work and not ideally suited for DIY repairs. Even many so called professionals are somewhat unsure about them.

Tony

 

[Graham81]

Thanks for the reply. System pressue is set to 1.5 bar cold but I just noticed that when hot water is demanded the pressue gauge goes slightly haywire & rapidly shakes and the shaking matches the fluttering/train like sound.

Do these models have expansion tanks; could that be at fault?

Thanks

 

[Graham81]

Just did some reading up & I have found the DHW expansion tank hiden behind a plate; I assume I can take the valve cap off & check the pre-charge pressure once the system is cold?

 

[Agile]

The DHW expansion tank is pretty irrelevant ( when fitted ).

Furthermore, the presssure its best set to depends on the incomming water pressure! It can also be higher than achievable with a car foot pump!

Tony

 

[Graham81]

Oh yes just realised the CH expansion tank is the large disc shaped one fitted on the rear of the boiler. Is it even possible to get to the recharge valve as I cannot see how?

 

[1983]

Think the valve is on the side of that one. Have a look at the rear, it's there somewhere. Might be that it's goosed anyway considering the age of this boiler now. You could fit an aftermarket one to return pipe for a faction of the cost of the manufacturers one.
You also need to check the pipe that connects the vessel isn't blocked with crud. Please depressurise vessel before disconnecting or you might get a nice shower in black stuff.
Is the hot water flow rate really slow??
Just edited to add that the noise sounds like its overheating when the waters on.

 

[ianmcd]

Ha Ha listen to 1983 I have been there and he couldnt be more right you will get black **** everywhere if you dont discharge the pressure vessel, you will never do it twice

 

[1983]

Very true, glad im not the only one thats done that
Done it once years ago. Spent more time cleaning up than fixing the boiler!!