Radiators not working in house extension

Funnyonion79

Hi,

I'm wondering if anyone can offer any suggestions on what might be possibly causing this problem:

We bought a new house a few weeks ago which would've been built back in the 70's. The house was orginally a 3 bed semi-detached but has a one storey extension built onto the side of it, making it a 5 bedroomed house, with an extra bathroom upstairs and an extra sitting room downstairs.

It has gas heating and a brand new gas boiler (with a new pump) was fitted about 2 years ago, however when I turn on the heat, the radiators in the upper part of the extension don't work. They stay cold. We've tried bleeding the radiators in case there's an airlock but there doesn't seem to be one and I've tried putting on the heat and turning off all the radiators apart from the 3 upstairs in the extension to see if this helps, but no joy.

Would anyone have any ideas? As the problem radiators are in two bedrooms and the extra bathroom in the extension part of the house, I'm wondering if there could be a switch or a valve perhaps that shuts off the heat in that part of the house - as the previous owner wouldn't have used that part of the house much. I've checked the hotpress but there's nothing there.

I've emailed the estate agent to ask the owner if there's something we're missing or if there's an actual problem with the radiators in that part of the house, but just thought I'd ask here in the meantime to see if anyone has any ideas as to what could be causing the problem or if you think there may be a valve that isn't switched on and if so - where would it be..?

Thanks!

crosstownk

Lots of things could be causing this.

You say you have bled the rads. Have you topped up the system after bleeding? In a closed system, bleeding reduces pressure which will need to be topped up. Locate the pressure gauge - it's usually close to the boiler. It should read around 1 bar. If it's much less or at zero then you'll need to find the filling valve and open it briefly to top it up to 1.0/1.5 bar. I'm assuming you have a sealed system.

There could be a valve just for the 'extension' rads (unlikely) but if there is you'll just have to find it.

Do the rads in question have TRVs fitted? If so they may be stuck closed.

Funnyonion79

crosstownk wrote: »

Lots of things could be causing this.

You say you have bled the rads. Have you topped up the system after bleeding? In a closed system, bleeding reduces pressure which will need to be topped up. Locate the pressure gauge - it's usually close to the boiler. It should read around 1 bar. If it's much less or at zero then you'll need to find the filling valve and open it briefly to top it up to 1.0/1.5 bar. I'm assuming you have a sealed system.

There could be a valve just for the 'extension' rads (unlikely) but if there is you'll just have to find it.

Do the rads in question have TRVs fitted? If so they may be stuck closed.

Hi, thanks for the reply.

I know nothing at all about radiators and heating systems and have moved from an apartment that had storage heaters to this house with gas, so please bear with me

I don't know if we have a sealed system but we just bled the rads and didn't top anything up so makes sense to do so. I'll check the boiler and see if I can see the pressure gauge.

If it's less than 1.0 - this filling valve that you mentioned - would it be a little red wheel that's in the hotpress on the floor beside the tank? There's only one of these in the hotpress - is this what's used to "balance" the whole system and if the pressure gauge is under 1.0, then I'd need to twist this little red wheel to increase the pressure...?

What's a TRV? The rads are old and most of them are missing caps so to ensure that they are all on, we used a vicegrips to turn them on all the way (anticlockwise). Each rad has a nut either side at the bottom - is one of these a TRV? We have opened each nut on each side of the rad fully but the 3 rads in the extension remain cold.

Apologies again for my ignorance.

To get a plumber out to look at this problem - any idea what I could expect to pay?

Thanks!

crosstownk

If it's a sealed (closed) system the filling valve will be in the off position. Opening it will see an almost immediate rise in the gauge if system pressure is low. It's not used to balance the system - it simply fills the system with water and it should only be opened to fill and closed for normal operation. Be sure that the boiler is when filling.

Balancing the system is getting the right balance between radiators. It ensures that a radiator close to the boiler is not getting too much hot system water that results in a distant radiator not getting enough. This is done by adjusting the lockshield valve to reduce flow through the radiator. The lockshield valve is the valve on a radiator that can't be adjusted without removing the cover and using a grips.

TRVs are valves on the radiator that turn off the rad when a certain temperature is reached. The valves are usually numbered 1-5 or similar. There are many different types but generally they look like this > http://www.boilersonline.com/default/boilers-radiators/central-heating-controls/thermostatic-radiator-valves.html