puma 80e ch problem

[gn350]

Help,
my puma 80e is playing up, DHW is working fine, but CH works only when it feels like it, it seems to light up for about 30 secs then stops and keeps repeating this every 5 mins or so, therefore not really heating the rads. sufficientlly, but will always light up instantly when a hot water tap is turned on. water pressure is 1-1.5 bar, room stat is set high, CH temp control is set max. fan is running, pump seems to turn ok. I have changed frost protection switch and boiler overheat stat. inspected the modulator board (as i have previosly repaired by soldering live feed on top left corner). I have noticed some arcing on relay 2 when boiler shuts down. All rads are bled. not sure what to check next as I am not a heating engineer but a reasonable mechanic. Any suggestions please to help me fix this so I can get the mrs. of my back.

 

[kevplumb]

check the diverter valve is working on heating do the pipes to the rads get hot

 

[gn350]

thanks for the quick response,
the pipes to the rads slightly warm up, some more than others depending on how long and frequent the burner decides to work for.
How do I check the diverter valve, cheers.

 

[kevplumb]

would think its the wax capsule gone but its not much cheaper than a new valve

run the h/w feel the central heating pipes
they should stay the same temp

then run the heating they should get HOT quick
if not i would be looking at the valve

the reason the boiler is going on and off (cycling)is because the heat aint going anywere

 

[ChrisR]

Can you check the resistance of the ch flow temp sensor?
WHen on CH, how hot does the flow pipe get?

Instructions etc are here http://www.partsarena.com/baxi/

 

[kevplumb]

aha fellow insomniac

 

[weargas]

come on chris and kev. first thing to check is to make sure there's no drippers.
must have been too late at night.
too much alkyhol?????

 

[kevplumb]

 

[gn350]

Hi
thanks for the tips and I have checked the following,
CH temp sensor is 12.3 kohms cold and 0.7 kohms hot.
With the ch on the flow pipe to the diverter heats very quickly to an untouchable temp but the flow on the outlet side of the diverter is very slow to warm up.
turning a hot water tap on makes no difference to the ch flow pipe.
Does this prove its the diverter if so is it just the wax capsule or the whole assembly I need.
I look forward to your reply.

 

[kevplumb]

do you have any dripping hot taps

 

[gn350]

no taps dripping all turned securely off.

 

[kevplumb]

difference in price is a joke about a tenner
wait for chris he will prob have 1

 

[ChrisR]

Your're right wearman. I've even forgotten to hit the switch for "heating + water" before now.

As a check you can heat the front end of the diverter valve - real men use blowlamps. Don't overdo it, but if the diverting gets better then its probably just the wax capsule. But you'd feel a blod if you bought just that then needed to buy the whole thing.

Yes I daresay I have a DV here somewhere. Email me ifyou like. Better hurry though I'm away for crimbo.

Your temp sensor is inside the spec by the way. If you really really want to be sure to be sure that the problem isn't a dripping tap, turn off the cold water feed to the boiler at the tap underneath.

 

[gn350]

Thanks Chris - but unless you live near in the Camberley Surrey area so we can collect we'll have to buy one locally as the post prob won't get to us in time - although can you let me know how much ???

 

[ChrisR]

£40. Paypal (4%) is instant, Special D cost £5 but g'tees next day.