Potterton Netaheat Profile problem

Superspec · 29 Jan 2008

Hi guys,

I moved into my house 18 months ago and the central heating system has worked perfectly during that time. The house was built circa 15 years ago so I think the boiler is the original one.

Yesterday when I got up I noticed the house was very cold - the central heating wasn't working. The hot water was fine and its thermostat has switched off the boiler. The room thermostat seems to be working ok in as much as it is switching (I can hear it click) when the temperature dial is moved and the indicator lights are lit up.

If I turn up the boiler thermostat the system kicks in and works fine (including the central heating) until the water reaches the new temp.

Also, if I increase the setting on the boiler thermostat (the one on the case) the boiler kicks in and everything is fine.

I'm guessing this is an electrical problem but not sure what to blame!!

The system use a 3 way valve so water and CH are independant.

Any ideas?

Cheers

heatingman · 29 Jan 2008

From your details it sounds like the motor within 3 port valve, depends on make if replaceable.

oakland99 · 29 Jan 2008

your post is a bit confusing you say the heating didn't work but the water did and had shut off on thermostat,, then you say central heating is fine when you turn the boiler stat up ???? it sounds like your motor has gone in 3 way valve or if rads get a bit hot it could be pump

Superspec · 29 Jan 2008

Sorry!! Yeah, I can make the whole system work perfectly well by turing up the water thermostat or the boiler thermostat. The motorised vale is cycling properly. The problem seems to be that the water stat is shutting down the boiler irrespective of what the room stat it telling it!!

oakland99 · 29 Jan 2008

with the clock on heating only is anything happening does pump run boiler work or valve motor over or is everything dead

Superspec · 30 Jan 2008

If the heating is the only bit switched on at the clock nothing happens at all. Everything is dead.

ChrisR · 30 Jan 2008

CHeck the wiring - faults like this often go unnoticed for ages.
If you're sure it's ok, change the valve head.

Superspec · 30 Jan 2008

I don't think its the valve head, I took it off last night and got the Mrs to switch controls on and off and the valve works fine. Only time it did nothing was when the heating only was called - it didn't move at all then.

Its definately an electrical issue and it sits with either the clock or the room stat, or maybe the junction box!! Nothing has changed though or been moved so I can't see how the junction box wiring could just fail.

My money at the moment is on the clock but I don't know if there is a way to test without replacing it. I'm sure there is but I would need wiring diagrams and the previous owners didn't leave any instructions.

topgazza · 30 Jan 2008

Whats the model of clock/programmer ?

Superspec · 30 Jan 2008

Right, well it isn't the room stat!! I've changed it for a new one. Going to swap the clock now. Old one was a Potterton EP2001. Looks untidy anyway, PIA job though because the backing plate need swapping too

topgazza · 30 Jan 2008

Might be a wise move..mine is an EP2000..possibly very similar..and yes they are ugly..mines brown and I hide it behind a large vase. I have the manual somewhere which is why I asked ....but if you're replacing it then fine

ChrisR · 30 Jan 2008

I don't think its the valve head, I took it off last night and got the Mrs to switch controls on and off and the valve works fine. Only time it did nothing was when the heating only was called - it didn't move at all then.

So the head isn't doing what it's told. How do you deduce from that , that the head is fine

Superspec · 30 Jan 2008

Good point Chris!! The motor was moving it turns out, just VERY slowly when switched to heating. It moves very quickly to water side but I think this is just because of the spring. The motor was VERY hot though so I swapped it for a new one and all seemed to be fine.

I thought I had cured it (it seemed to be doing what it should) but the problem is still there. The new valve motor is also running very hot, almost to hot to touch and it feels like it is trying to move constantly.

As things stand the pump is running when the heating is switched on but the boiler doesn't fire up. If the water is switched on the boiler kicks in straight away and the radiators get hot. As soon as the water reaches the required temp the boiler shuts down. The pump is still running but the water just cools down and the radiators go cold.

Not sure where to look next. I've fitted new room stat, new controller clock, new synchronous motor.

Thinking about it, I decorated one of the bedrooms last week and took the radiator off (I refitted it on Saurday) and first noticed the problem on Monday morning. I noticed tonight that for about 30 seconds or so that there sounded to be a lot of air in the water, it went away though!!

I think I might get a heating engineer to come and have a look, I've done what I know how to do, I don't fancy messing with anything else unless it is fairly simple!!

JohnD · 31 Jan 2008

you recently took a rad off?

How sure are you that the system is full of water?

Often a blocked cold feed only manifests itself after you have taken a rad off for decorating. When you refit it, the system tries to fill up the new rad, but with a feed blockage, the water level drops and you have air and little pressure on the upper floor.

If you bleed the highest rad in the house, does water squirt out vigorously?

If you tie up the float in the F&E and drain a bucket of water out of the drain cock, does the water level in the F&E drop by the same amount?

diynot

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

Potterton Netaheat Profile problem

oakland99

oakland99

Similar threads