potterton puma 80e problem

[kevino]

Hi,

I've just started to experience a problem with my potterton puma 80e combi boiler:
when I switch it on (from standby, with CH off) it 'fires up' and stays on (without
any hot water taps running) and after a few minutes a rather alarming rumbling/
hissing sounds developes and then often locksout.
The boiler is 9 years old and I haven't previously had any problems.
Prior to this happening, I had to reduce the mains pressure (at the stopcock)
for a few days as I'd got a leaking pipe elsewhere in the house.
Any help will be much appreciated.
Regards,

Kevin

 

[kevplumb]

hot water flow switch is stuck on

 

[kevino]

thanks.
Is there a way to tell whether this is due to the switch being broken or whether something
else that controls it (like a temperature sensor) is broken?
Also, the manual refers to 2 switches:

5.21 Water Flow Switch D.H.W
5.22 Microswitch (D.H.W Flow Switch)

ps Although I have access to a puma 80e manual online, unfortunately, the
fault finding flowcharts are too small to read

 

[kevplumb]

the microswitch is fitted to the flowswitch

the plunger is prob stuck

there is a red led on the board that will probably be lit

 

[kevino]

thanks - I'll take a closer look later

 

[kevino]

great - you are correct In fact, just pushing the switch back in with a
screw driver (to loosen it) has (at least temporarily) fixed the problem.
Thanks again