Potterton Puma 80e combi problem

[cerpnjak]

Hi there,
I'm not sure if this has been covered in the past, I apologise if it has.
Basically my hot water works fine, nice and hot, however recently the central heating has not been working properly. For the last 3 or 4 days the CH hasn't come on in the morning or the evening while being set to timer and even when you flick the switch to constant it still doesn't work. It does however fire up and sound like it's working for say 20-30 seconds and then turns off again and stays off for ages again. The pipe coming directly from the boiler to the first radiator is really hot but as you follow it to the radiator it gets cooler and cooler and hot water doesn't reach any of the rads in the flat, we've only 4 it's a small flat!
Does anyone have any ideas as to what might be happening? I've read other posts and I'm thinking it could be something to do with pressure in the system but I'm not sure?
Any help would be greatly appreciated, thanks in advance
Pete

 

[twgas]

you may be right about the pressure in the system, you need to locate a presure gauge and make sure its on about 1bar. or check to see if you have a small header tank, with water in. if you have water in system try bleeding rads, check pins in TRVs are not stuck, check motorised valve(s) are working.

 

[timmy74]

Have you got any dripping hot water taps? If so turn off the mains cold stop tap presuming the pressure in the boiler is ok try the heating if it works fine then you need to get yer hot water taps fixed

 

[bav]

Pete, I have the same boiler and have had the same problem. This is the diverter valve. This is not difficult to change. You just need to change the front part and the valve, which is held by two grub screws. These screws can be removed with an Alan Key and the front twists off. Don't forget to turn off the water from the main stop tap and drain the boiler of water first. This will sort your problem.

 

[cerpnjak]

blimey that's what I call an efficient service!!
Thanks guys for all your suggestions. Right I've just checked the pressure gauge underneath the boiler and it looks like it is on about 0.5 BAR. What does this mean? I know I've read it should be between 1 and 1.5, how do I fix this? Is this something I could possibly do or would it be a job for an engineer? I checked the taps I they don't seem to be leaking.
Thanks again for your help and advice
Pete

 

[timmy74]

Is there a chrome tap on one of the pipes below or nr the boiler open this and the pressure should go up, be careful not to put too much in though.

 

[fitz1]

look for a flexible hose around near the boiler pipework with a small tap on it or a screwdriver slot in the middle. Turn it and watch the pressure rise. Stop at about 1 to 1.5 bar.

 

[bengasman]

Look for a filling loop, pictures on faq section.
This is the first step and you can do that yourself, it is officially a user operation
If that does not cure the problem, the diverter valve is a known problem on these.
You need to be fairly apt with tools and understand the basics of a sealed system combbi.

 

[cerpnjak]

OK that's great thanks. Do I need to turn the boiler off at the mains to fix the pressure, I did see the silver pipe earlier so that's a good start!?
One other question, what do you think the reason is why the pressure should drop and do you think that this could be a recurring problem?
Many thanks again
Pete

 

[fitz1]

constant loss of pressure is either a leak on system or faulty pressure relief valve or faulty or depressurised pressure vessel.

 

[Agile]

you may be right about the pressure in the system, you need to locate a presure gauge and make sure its on about 1bar. or check to see if you have a small header tank, with water in. if you have water in system try bleeding rads, check pins in TRVs are not stuck, check motorised valve(s) are working.

Surely you know where the gauge is on a Puma?

 

[bengasman]

you may be right about the pressure in the system, you need to locate a presure gauge and make sure its on about 1bar. or check to see if you have a small header tank, with water in. if you have water in system try bleeding rads, check pins in TRVs are not stuck, check motorised valve(s) are working.

Surely you know where the gauge is on a Puma?

ON a puma?