DIY Doctor UK DIY Forums

I have a POTTERTON PUMA 100E. everytime the burning trips out you can stil hear what sounds like the pump/fan still going for a good 5 mins or so before the burning clicks in again, ( and thats when its been good ) a friend said the boiler may be furred up and so is takin longer to cool down, if this is so how can i cure it?
also if i use the water for any length of time the radiators go stone cold and then takes another hour or so for the heating to start working properly again,
any help would help. Thankyou

Combi boilers give priority to hot water, if you run the bath you may find the heating will cool down abit, but unless your running the bath for 45mins to an hour - they shouldn't get cold.

With the radiators cooling down that much, it's probably the wax capsule sticking, get a Heating engineer to replace it.

The see if this is the problem, after using the hot water turn the boiler to standby - if it doesn't change across to heating - run the hot tap. This will allow cold water to run through the wax capsule and the capsule will shrink, then turn the boiler on and the heating should come straight on.

The pump will run continuously as long as the heating is on, the boiler burner will cycle on and off. The pump will also run after the timer has clicked off - known as pump over run. This gets rid of excess heat and prevents damage to the boiler.

Thankyou very much i shall give the latter a go, if this proves to be the problem i shall get intouch with a gas engineer to sort out the wax capsule.
once again thankyou

just another quick question, using the face of a clock as a guild, min been 7 oclock, middle been 12ish, max been 5 oclock (hope you understand that) where on the clock would we expect to be setting the temp at this time of the year.
we are at the moment having to put it at 3 oclock sometimes more just to get ALL the radiators to get hot enough, I have been round and balanced them so i dont think its that. boiler is in unstairs, we have 3 rads upstairs then 3 in livingroom/dining room, 2 in kitchen, and 3 more to front of the house which happen to be the last in the chain and the ones that we sometimes have problems with. if the boler was furred up would it be a big job to sort or could a woman like me have a try.

Thankyou very much for getting back to me so quick.

I shall give the latter a go and if this proves to be the problem get an engineer out to fix it.

Thankyou once again

It could be that the pump isn't working as well as it should be, or the inpeller has came away from the pump motor _seen this a couple of times on puma's) - this could be why the radiators aren't heating.

Most puma's I work on, they have them set to maximum in the winter or at 3o'clock but your radiators should be v.hot.

after running a bath i did as advised last night, i thought it had worked as the heating kicked in but after a 20 30 seconds turned of again, i had to redo the running of water for it to kick in again, after 1-2 hours it started working properly on its own, but as soon as the hot water was used again we were left with the same problem, i cant think what else to do to keep us going through xmas, so thankyou for all your help but it looks like we will be needing a new boiler in the new year.

you don't need a new boiler - the wax capsule it sticking, so the central wont come on until the wax capsule has cooled down. As you said if you run the hot tap so that cold water passes through it thens works again until the hot tap is used.

Wax divertor valve £112.91 + vat, alot cheaper than a new boiler, I work on puma's quite abit, puma's are quite a good boiler and parts are easy to change.

Get a price for someone to install it. Are you a competent DIYer ? you're not breaking any gas supplies or altering anything that effects the safety of the boiler. If you want me to run through what to do - let me know.

Many thanks for your help, my husband is a very good DIY'er so will try and find a supplier for the diverter valve, as looking at the telephone book we do not have one near, ie near HULL. my husband has looked at the manual and has located were the T piece is and if needed would like to take you up on your offer of help,
Again a really big thankyou, and a Very Happy New Year is wished to you and yours.

Hi There
I have finally had time to sort out the Diverter Valve Assembly Complete,
which my hubby will be doing this weekend hopefully,
You offered some guildance on this problem, could I please use your expertise and ask you for ways in which to complete the job with as little fuss and mess as possible for my husband.
Many Thanks to you in advance and for all the help and advise given to us so far.

Hi there Htg Engineer, fitted the new diverter valve, water and heating never been so warm and it doesnt go cold when the hot water is run (its great), only problem we seem to be having now is the burners dont seem to cutting off, radiators are getting as hot as the temp we set but the burner will not cut in and out as it should, we have also put the heating knob at the lowest setting and this doesnt seem to make any difference either, any idea's ??? we think maybe the temp sensor, or could there be something we havent done when we fitted the diverter valve.
thankyou

When you put the heating on, it just keeps heating and doesn't cut out ? Could be the heating sensor.

It must cut out once the temperature is reached otherwise it would shut down and lockout as it would over heat.

The burner would have been cutting out more than it should have before, as the diverter was sending the heat down the DHW draw off, are you confusing how it should work to how it worked with the fault ?

I'm sure the diverter is fine. Glad you got it sorted, Sorry i didn't see your last post. I'm sure you found it fairly easy to replace the diverter.

Hi Terriwilk - sorry to hijack your thread but I have an almost identical problem with a Puma 80 and wanted to run something by Htg Engineer before I replace the diverter valve.

Hi Htg Engineer – in one of your earlier posts you mentioned you had seen the impellor come away from the pump motor. I tried the “cold/hot water testâ€

If tapping the pump got the heating working then the pump could have just been stuck. If you wanted to leave it at that you could.

But - if the pump was to get stuck and overheat so that the electrics melted it could also affect other parts of the boiler for example the PCB. Which are pricey.

If it happens again then I would definately suggest fitting a new pump.

Thanks - I decided to take the head off to see if there was anything obvious and found a bit of broken gasket in the impeller. Put it back on and it seems to be working fine now. One thing though, the impeller was free to move independantly of the pump (but moves with the pump if you turn it manually) - I take it that's by design?