Heating not kicking in

[monkeymagoo]

Hi

I've got a Portterton (Supreme1?) boiler, and a basic thermostat in the living room. I had a Potterton EP2002 heating control in the kitchen (where the boiler is). I had to replace the control because the slide switches (for timed, constant, once etc) had been broken and the metal contacts inside weren't making contact. So, I replaced that with the EP3002 which is compatible.

Now, when the timer kicks in, the lights illuminate for CH and HW, but the boiler doesn't always kick in. Sometimes I will set the time for e.g. 5 minutes time, and wait. When 5 mins is up, the lights come on, and maybe 30 seconds later, I will see the boiler fire up. But, like this morning, I'll wake up to a freezing cold house, even though the lights on the control panel are illuminated.

I have noticed that if I move the thermostat to a low temperature, wait a few seconds, then move it past about 20 degrees, there is an audible click. Then I hear the boiler firing up in the kitchen. So my first guess is that the thermostat isn't working quite right.

Also, when the boiler is working, there is a fair bit of churning in the radiators, so I think they are full of air... (I seem to have to bleed them once a week...).

Finally, even when the heating is on constantly, the radiators may be very hot for perhaps an hour, but after that they go cold again for the rest of the evening, unless I manually intervene.

Would appreciate any help. I'm not qualified and only have basic knowledge of CH, so I want to try and understand the problem before I get an engineer out which may cost a lot!

Cheers

 

[twgas]

sounds as though you have more than one problem.

firstly the air/water noise/bleeding is usually caused by either an incorrectly piped system or a partial blockage.

the problem with heating not firing up could be broken or wrongly wired motorised valve, or room stat.

at least these are some starting points

 

[monkeymagoo]

Thanks for the quick reply.

Do you think it's better to get a heating engineer out then (rather than attempting to fix it myself)? I can probably just about manage to replace the thermostat, but if it's anything more complex, I don't think I stand much of a chance.

Just wary of getting ripped off since I don't really know what I'm doing...

 

[twgas]

if you're not confident then it is probably worth getting an engineer to have a look.

try asking for an idea of cost first, and make sure he tells you if any parts are reqd etc.

check his corgi card.

 

[ChrisR]

The programmer may not have good connections, if you used the old backplate. I forget whether they're pins or bits of bent metal. Have a look. If the latter, with power properly off, bend the metal slightly to make stronger contact withthe front part when you replace it.

If the thermostat works sometimes, it's unlikely to be faulty.

The thing which actually turns the boiler on will be a motorised valve (see faq'a) which may be sticking - depends whether you have one with 3 pipes or two with two. See what you can find - typically in the airing cupd.

 

[twgas]

I forget whether they're pins or bits of bent metal

surprised you don't have a pic, chris

 

[monkeymagoo]

I did use the old back plate actually, so I'll try wiring up the new one this evening and see if that helps.

Thanks for the tips!