Potterton puma 80 H/W keeps going hot and cold

[Staples6961]

Help please,
when turning my taps on the hot water takes quite a while to come through. When it finally does it only stays hot for a short while and then goes cold again.This cycle keeps happening which stops me getting constant hot water making it very difficult to fill up a bath. When the central heating is on it doesn't take quite as long for the water to get hot but its still longer than it should be and it still goes through the hot and cold cycle.

Can anyone please explain whats wrong and how i should go about fixing it.

Thankyou

 

[GodKnows]

Hi all,

Have you had the appliance serviced regularly? If not, there could be a number of faults associated with your boiler. DHW flow regulator, DHW diaphram, DHW flow sensor, water pressure and gas valve. You need a competent Gas Engineer to look at it, is there a washing machine below the boiler as well?

 

[baxpoti]

Does your central heating warm up when there is demand for hot water only?

 

[Staples6961]

the previous owners serviced it regulary but i haven't since june last year. guess i'll call a pro out to have a look. also my central heating works fine, just the DHW which is the problem.

Thanks for your replies