Puma 80 combi boiler - water goes hot then cold

[londonlad]

hello

i have just moved into a flat with a puma 80 combi boiler. When a hot tap is turned on the flame kicks in and water goes hot. The flame then goes off as water is presumably hot enough but the problem is the flame does not kick in again until water is coming out cold from the tap. This makes having a shower a total nightmare!

any ideas on what causes this and how much it would cost to have fixed?

thanks for your help!

 

[assured heating]

sounds like the wax capsul is faulty but i dont think these are available seperate you have to buy the whole divertor valve you are probibly looking at £220 they are a pig to do

 

[Agile]

It sounds to me as if its overheating. That may be because the pump is not turning on DHW.

Does it work OK on CH?

We charge a fixed price diagnostic fee of £84 in our local area with any parts extra.

Might need new pump (£65) or possibly PCB ( £94) or an overheat stat (£20) or it might need cleaning ( (£60 ? )

Tony

 

[londonlad]

thanks for the replies.

i have just done some more testing....

with the central heating turned on the problem goes away.
it only happens when central heating is turned off - would that help identify the cause?

also it takes around 17 seconds to fill 1litre of hot water - is that a normal flow rate for this type of boiler.

many thanks for your help!

 

[Soggy_weetabix]

sounds like the wax capsul is faulty but i dont think these are available seperate you have to buy the whole divertor valve you are probibly looking at £220 they are a pig to do

You are wrong here.

I buy my wax capsules from abcotuk.co.uk

The divertor is not a bad job as long as you can get the akward connection out. Many answers on this site to how you remove it. An hour to replace the whole divertor, 20 mins for the capsule, which is around a 50 quid job if its a successful repair. Id do a whole divertor for 175 notes.

THIS IS NOT AN ADVERTISMENT!

I live 30 miles away and have no intention of doing this job. Just givivng honest advice.

 

[Soggy_weetabix]

Just a quick add

I would suspect your plate to plate heat ex.

Dont think the diverter is faulty

 

[Agile]

Just a quick add

I would suspect your plate to plate heat ex.

Dont think the diverter is faulty

You are correct that the diverter valve is not faulty.

But as for a plate HE on a Puma ???

Tony

 

[Soggy_weetabix]

blonde moment Tony

 

[ollski]

MOD - why is the link and post to a webpage showing how to do the specific job mentioned in the post removed?

 

[assured heating]

sounds like the wax capsul is faulty but i dont think these are available seperate you have to buy the whole divertor valve you are probibly looking at £220 they are a pig to do

You are wrong here.

I buy my wax capsules from abcotuk.co.uk

The divertor is not a bad job as long as you can get the akward connection out. Many answers on this site to how you remove it. An hour to replace the whole divertor, 20 mins for the capsule, which is around a 50 quid job if its a successful repair. Id do a whole divertor for 175 notes.

THIS IS NOT AN ADVERTISMENT!

I live 30 miles away and have no intention of doing this job. Just givivng honest advice.

You're to cheap if i get any in befordshire i'll get you to do them and pocket £50 lol

 

[assured heating]

Just a quick add

I would suspect your plate to plate heat ex.

Dont think the diverter is faulty

They dont have plate heat exchanger

 

[assured heating]

It sounds to me as if its overheating. That may be because the pump is not turning on DHW.

Does it work OK on CH?

We charge a fixed price diagnostic fee of £84 in our local area with any parts extra.

Might need new pump (£65) or possibly PCB ( £94) or an overheat stat (£20) or it might need cleaning ( (£60 ? )

Tony

agile forgive me but on the puma when you demand hot water the water comes out very slowly then when the wax capsule heats up it releases and you get full hot water flow if the wax capsul sticks shut this can cause the boiler to get very hot espically as they are getting on a bit, this can cause the boiler to shut on and off on the thermister and sometimes lock out .
What do you think?

 

[Agile]

If th gas valve minimum is correctly set then they will happily deliver the correct temperature even if the flow regulator was stuck.

I have never seen one stuck yet.

I still think that, as I said before, the boiler is overheating. But then I have not been to this boiler.

Oddly he said the problem is not there if teh CH is turned on. That makes me think the problem is connected with the pump not running for DHW. But until someone tells us if the pump is running on DHW we will remain in the dark.

Tony

 

[assured heating]

cheers Tony