I run my central heating and the boiler ignites for about 20 seconds then stops. it will not run again for a long time. but if I run the hot water the boiler ignites and runs ok until I turn the tap off the boiler runs for another 10 seconds then goes off. 10seconds later the pilot light goes out. I believe it is a stat. but which one,This happened at the end of last year but everything started to work ok again. now the problem has returned can anybody help

Bill Conner, January 2005

How could you change potterton puma fan.
My boiler fan does not work properly. when it works heat water when it does not work water does not get heated. Is there any advice for me from any one .
Thank you.

R. Tapader, November 2013

Hi Guys,
I have a Potterton Puma 80 which provides very low hot water pressure. Another forum suggected it might be an inline filter. Could anyone either agree or suggest any DiY solutions please.

Thank you-Steve.

Steve Anniss., February 2012

Had same prob - guess what after dismantling it a little found out it was pessure, topped up tank and found a hot tap slightly dripping. so all good now fingers crossed for another 16 yrs !

Ace, January 2011

the problem with the boiler running on then locking out in the microswitch for the hot water which tells the boiler when to switch on and off, the microswitch is located on the bottom left hand side behind the electrics, it probably only needs adjusting a natts c..k, when the boiler runs on it over heats and the over heat thermostate kicksin thus locking out the boiler.

rj, January 2011

puma's use a wax capule in the divertor valve, when cold mains water moves across it via the 'hot' taps the wax shinks closing the central heating port. a separate diaphram flow switch makes a microswitch turning on boiler, giving hot water (no heating). when water tap is off flow microswitch should be off and boiler stops. turn heating on, boiler again fires, however as tap is off no cold water is crossing was capule so it should expand pushing central heating port open. if there is a dripping hot tap, winter incoming very cold water will keep wax shunk, warmer incoming water may not, try turning off incoming water to taps under boiler at its service cock. if heating comes on after a minute then attend to drip or small leak on hot water outlets, if boiler still won't give heating then wax capule in divertor valve or valve is stuck, change it

deano, November 2010

i have moved into a new home and the boiler has potterton puma 80 has always worked fine. Now its cold and ive started to use the central heating im getting problems.
If i switch the heating to constant, the boiler comes on but after 15 - 20 seconds it releases pressure from the top valve and the boiler switches off. It then tries to kick back into action 1 or 2 more times but the locks out. The pressure is about 2 bar so should be ok.

Steve, November 2010

Hi I have the same problem, but what would cause a lockout?

Thanks

Robbie, April 2010

I just want to say thanks to Pat (3 posts up) in case he still uses the forum because I think his suggestion has just solved my central heating problem and saved me the cost of a boiler engineer - there is a permanently dripping hot tap in the bathroom in my new house...I've just fixed it and it seems to have sorted out the CH problem...!

Thanks

Olly

Olly, January 2010

Expansion vessel leaking changed all ok

Af, December 2009

i have a baxi 105e condenser boiler, when i switch the central heating on 9/10 times the burner ignites and then goes straight out it does come on and stay on when i run the hot water for 2-3 mins how do i resolve this

trev, February 2009

check the small hex on the pump turn anti clockwise to make sure pump is running because if the pump is not running the heat wont get away fast enough from the boiler resulting in the overheat causing the stat to cut out the boiler the stat in this case would be operating correctly

davy grier (corgi registered ), December 2008

Can you help me please ?

I have a problem with my Potterton Puma 80 combi-boiler. ( permanent pilot model )

When I use it for hot water only ( with central heating switched-off ), the boiler works just fine. No problems of any kind.

But.....

When I switch the central heating on, two types of problems occur :-

1. If the central heating stays on for more than 2 hours continously ( at night for example ), the system pressure gradually climbs-up from 1 Bar to 3 Bars and above, which causes the pressure release valve to open, and this in turn drops the system pressure right down to Zero Bars, which in turn turns-off the boiler due to low system pressure. If I then top-up the pressure back to 1 Bar and switch the central heating back on, the above cycle repeats itself on and on.... Basically when I'm using the central heating, the system pressure refuses to stabilise itself within its normal parameters, i.e. between 1 Bar and 2 Bars.

2. the second problem, which also occurs only when the central heating is switched on, is if I run the hot water continously for more than 10 minutes, the pilot light goes out. If I turn it back on, once again, after running the hot water for more tham 10 minutes, the pilot light goes out, and so on.....

Both problems only occur during the winter months when I'm using the central heating.

In the summer months, when only hot water is being used, neither one of these problems occur. The boiler works perfectly then.

I have replaced the electronic boards, but it didn't help.

Greg, December 2008

This is likely to be the wax capsule valve that controls the flow of heated water to the CH or the DHW.
Ours was broken and gave the same symptoms. Very common apparently. A small spare but you have to buy the whole valve assembly at about £80

Rich, April 2007

Well what happened? did that work, because I have the same problem right now and its got cold :(
many thanks
Quote: potterton puma 80?

I run my central heating and the boiler ignites for about 20 seconds then stops. it will not run again for a long time. but if I run the hot water the boiler ignites and runs ok until I turn the tap off the boiler runs for another 10 seconds then goes off. 10seconds later the pilot light goes out. I believe it is a stat. but which one,This happened at the end of last year but everything started to work ok again. now the problem has returned can anybody help

Harry Duff, January 2007

i had the same problem 2yrs running, try changing the universal coupling, also try checking the presure, 1 bar at cold, if the presure drops the pilot goes out. one reason i found for the drop was the spring in the release valve had gone weak and vented water at 1/2 bar, £21 for the valve, 2 allen screws and 2 nuts loosened later the leak was stopped. Hope this helps.

karl, November 2006

I had exectly the same problem - check for a dripping hot tap!! - apparently a well known niggle.

Pat, February 2005

DIVERTER VALVE STUCK IN HOT WATER MODE

STEVE@BH HEATING, January 2005

check out this web site: http://www.gas-news.co.uk/ I have a similar problem but a little more advanced, the whole system has now died... i have not yet tried the solution given on one of the chat threads but it seems to go a little like: The pilot head port to t/c was partially blocked - on full flame (hot water) the t/c held in - on reduced flame (c/htg after ramp down) the t/c dropped out. Cleaned pilot head with pin - now all OK. (sounds cheap enough to try first doesn't it!!)

Tony, January 2005