Another "I've got a Potterton Puma 80e problem" th

Evening all,

I'm encountering yet more issues with my Potterton Puma 80e and I'm wondering if you can help me diagnose the problems. My knowledge is basic at best.

Boiler is approximately 10 years old running 5 rads - very small system - in a first floor self contained flat with one rad downstairs at the door. Microbore piping. I am unaware of servicing history other than for the last 3 years when I moved in to the property and took out BG Homecare agreement.

I have another BG engineer booked for Saturday but had one out recently and he left without doing very much at all, giving me the ever popular sludge diagnosis and "you need a powerflush mate". I would like to be better prepared for the next visit!

I am currently experiencing:

1. Intermittent CH - HW water works fine but when room stat calls for heat from the boiler it fires for approx 30 secs and then shuts down, delay until system cools, repeat. All taps are closed and no sign of a leak. I have read
plenty here and elsewhere which suggests this might be the wax capsule in the diverter valve.

2. Loss of pressure - around 0.5 - 0.7 bar over a day or so. I've checked the Pressure Release Valve which seems to close properly but I am at a loss of what else to check. No apparent sign of leaks anywhere.

I would like to be able to start making suggestions to the BG engineer if he tries it on with the sludge defence again - have you checked this? could it be that? etc.

All advice / suggestions appreciated.

Thanks

IF you are considering to change wax capsule see this post

//www.diynot.com/forums/viewtopic.php?t=111198&start=0&postdays=0&postorder=asc&highlight=

I had changed wax capsule "easy way" it may work for you, it did for me.

My Puma was scrapped and I had changed it for a new boiler when it was approx 10 year old, by then it had 1 failed main PCB within warranty, Fan failed twice, Diverter valve, Pump, AAV, PRV, electrode gap had problems, blocked pipe for expansion vessel, leak on the rubber hose for air pressure SW, other than that it was fairly consistent, once a month pressure would drop for no apparent reason, (probably leak on PRV) and once I had seen mud pouring out of hot water tap. Still Can't say why )

The best thing about Puma is that when I moved in I had no idea how boiler works, by the time I had disposed of my old Puma i had reasonable understanding of the boiler operation. still have the old manual.

IF you like fixing things keep it if you like reliable water and heating system dispose of the Puma.

From the limited knowledge I have I would agree with you and would say wax capsule could be your problem.

But also failed or slow pump could be the problem, so test to make sure pump works.

To identify problem with diverter valve you need to feel the pipes leading to DV inside boiler, they are hot so take care, see plenty of posts on how to diagnose this.

Almost certainly your wax capsule(diverter valve),,,but hey i thought it was only B/g engineers that advised powerflush not Private engineers, they would never do such a thing!!!!!!!!!!!!!

hym said:

Almost certainly your wax capsule(diverter valve),,,but hey i thought it was only B/g engineers that advised powerflush not Private engineers, they would never do such a thing!!!!!!!!!!!!!

Click to expand...

ha! Yes it was a bg engineer last time. I've amended my first post now to make it clearer!

Thanks

Poor circulation means blocked rads, a blockage in the boiler, a slow/old/blocked/worn out pump, ot he diverter not diverting properly. It takes a bit of experience to judge the latter, because they divert slowly when they're old.
If anyone insists it's sludge, ask how they know it's not the pump or the DV. Bear in mind the HW works happily enough on a Puma with a dead pump.

Thanks. The pump is reasonably new - replaced maybe 8 months ago so I hope it's not gone again.

The annoying thing is the bg guy probably won't have any of the parts he needs on his van so will have to come back.

Anyone got any ideas what might be causing the loss of pressure?