Potterton puma 80e - Intermittent hot water

Joined
23 Mar 2004
Messages
2
Reaction score
0
Country
United Kingdom
I have a Potterton Puma 80e combi boiler that cuts out the domestic hot water after about 20 seconds, then refires after about one minute and repeats the process. When the central heating is on the problem doesn’t occur. As we are heading towards the summer I need to get it working without having the central heating on constantly.

The problem started a few months a go but has got worse recently. At first there only used to be a problem in the shower and on mixer taps but now it cuts out on running just hot water taps as well. Any ideas please?
 
Sponsored Links
one of three things

1. If you haven't got good flow rate from the taps then its your DHW wax capsule thermostat, located on the left of the boiler, with a large hexagonal nut on the bottom of the module.

2. Your flow diaphragm has stretched/torn hence the boiler is not firing on demand for hot water

3. The DHW microswitch has blown/malfunctioning, located towards the left centre of the boiler.

These can all be tested by a competent person quite easily, try and make the microswitch manually with a screwdriver to push the switch in (with the hot tap running) if the boiler fires its likely its your diaphragm.
Observe the DHW spindle when opening a hot tap (by opening a hot tap and turning the cold water on and off to the boiler), is it moving enough/at all? It can be adjusted as a short term fix to compensate diaphragm wear, but must be changed ultimately.
 
Sponsored Links
take the front off the boiler and switch on a dhw tap. watch the red led on the pcb. if it stays constantly lit (but the boiler still cuts out)then it's not a problem with dhw flow or the dhw microswitch. more than likely the dhw sensor, pcb or (far less likely) the wiring to and from each. pumas are renowned for pcb dry joints (they're on the 14th generation pcb for that boiler) so you could, if you feel confident enough remove the pcb and check the joints on the back side to see if any are cracked/charred. It also could be the air pressure switch dropping out but i do doubt that.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top