PROBLEM WITH POTTERTON PUMA

[REDNEKNELLIE]

Sorry if I am asking a repeated question, had a read through other posts and wasn't sure wether they were the same problem.

I have a potterton puma combi boiler and when you run the hot tap after quite a while the boiler fires up and gives hot water but then shuts off after ten seconds and the water runs through cold. Any suggestions will be greatly recived. Thanks.

 

[Agile]

Without knowing if you have the electronic or permanent pilot light its difficult to guess.

It would be helpful to know if the central heating is working.

My best guess is that its an electronic verson which is overheating, perhaps because the pump is seised.

Test on CH and spin the pump to see if its seized.

It should turn on at about 2 litres per minute and provide a flow of about 3.5 li/min until the water is hot then it increases to the full flow of 8-11 li/min.

Tony

 

[REDNEKNELLIE]

There are no warning lights that come up when it shut down, it just seems to turn off. Also you needs the taps a fair way open to get it to kick in. I will try to find out about the pilot and check the central heating. Thankyou Agile

 

[Baxi-Remeha]

sounds like it could be the wax capsual divertor not moving across....

 

[Agile]

If that was the fault then I would expect the boiler to heat the rads as well as the hot water.

However he says it goes cold.

Tony

 

[Alfredo]

We've only got one Puma on our patch that i know of.

I've changed the pcb on it, and a colleague changed the H.W. diaphragm I believe after problems not disimilar to those you are having. I bow to those with greater experience of this machine.

Alfredo

 

[corgiman]

sounds to me like partial blocked primaries?

but that said why aint it locking out? Blimey I am even arguing wif meself now. This site has alot to answer for

 

[Agile]

.....changed the H.W. diaphragm Alfredo

I doubt it ! I have never seen the diaphragm sold on its own. You have to buy the whole actuator unit.

Once when I was stuck I did manage to utilise a diaphragm from one of the instant water heaters but it was not the right part.

Tony

 

[Vic Spanner]

I have a potterton puma combi boiler and when you run the hot tap after quite a while the boiler fires up and gives hot water but then shuts off after ten seconds and the water runs through cold. Any suggestions will be greatly recived. Thanks.

When you open your hot tap what sequence does the boiler go through.
1.Do you hear a click.Red light on modulation board
2.Does fan start
3.Does main burner ignite straight away?
4.Does burner stay on?

Check your A.P.S tube that goes onto the fan housing for a split

 

[REDNEKNELLIE]

Last night I checked that the pump was free, and it was. I then checked the red light on the pcb came on when water was turned on, it came on then went of with burner after about 10 secs same as before. Whilst staring in dismay at the unit the missus used the tap and I noticed that the plunger on the hwd valve came out, tripped the micro switch and then slowly crept back in untill switch turned off, all this whilst the tap was still running. So what I have done for now is adjust the switch so that it only needs the plunger to move a little before cutting in. Having just moved in at the weekend have now managed to have a bath and wash up, can eat and smell less now.

I realise this may not be a permenant fix what do you think I should do next.

Cheers to everyone who posted help.

 

[Agile]

I think that it is very clear that you need to replace the diaphragm unit !

When adjusting there should be a gap of about 1 mm between the operating rod and the switch actuator.

Tony