Why are my radiators only half working?

Dannydee333

As the title suggests, most of my radiators are only half heating up.

I've just bought the place, and I tried to bleed them. However, as soon as I turn the valve to bleed them, water comes out immediately, instead of air.

They seem to warm up on some of the radiators, and the rest stay cold. The one in the bathroom does not heat up at all (it's one of those for hanging towels on).

Here is the breakdown:

Main bedroom - the top third of it is warm, the rest is cold

En suite bathroom - top half warm, the rest is cold

Guest bedroom - most of it is warm, the very bottom is cold

Hallway - most of it is warm, the very bottom is cold

Main bathroom - does not come on at all (hot water comes to the bottom left pipe)

Living room - top third warm, the rest is cold

Kitchen - most of it is warm, the very bottom is cold

Office - the whole thing seems to be warm

What else can I do? Can air be trapped deep within the radiator and you just let the water keep coming out until the air escapes?

I'm open to doing DIY even tho it'll be annoying because I'd much prefer to focus on decorating.

I've heard about some radiator flushing solutions you can try.

I'll be really peeved if the seller has left me with a problem that becomes a significant maintenance cost.

BarelySentientAI

Sounds like radiator sludge to me - at least on the ones that are warm at the top and cold at the bottom.  It's not air.

Either that or the valves are nearly closed and there's just no water going through.

Dannydee333

BarelySentientAI said:

Sounds like radiator sludge to me - at least on the ones that are warm at the top and cold at the bottom.  It's not air.

Either that or the valves are nearly closed and there's just no water going through.

I believe the place has been barely lived in for a few years so it could be the sludge.

However, I'll try the valves first. I take it that's just the valves/nuts where the pipe comes from the ground and joins the radiator?

ThisIsWeird

Hi DDee.

BSA1 has given you the two most likely scenarios. One - the setting of the rad valves - is easy to test.

Could you post a photo of one of the main culprits, please - show the rad and the valves on each side. Choose a smallish rad that has a cold bottom (missus!), because the next step may require it to be removed for cleaning

Also, what 'type' of CH system do you have? Make and model of boiler, whether it has a hot storage cylinder, and whether there are ColdWaterStorage tanks in the loft.

Dannydee333

ThisIsWeird said:

Hi DDee.

BSA1 has given you the two most likely scenarios. One - the setting of the rad valves - is easy to test.

Could you post a photo of one of the main culprits, please - show the rad and the valves on each side. Choose a smallish rad that has a cold bottom (missus!), because the next step may require it to be removed for cleaning

Also, what 'type' of CH system do you have? Make and model of boiler, whether it has a hot storage cylinder, and whether there are ColdWaterStorage tanks in the loft.

Thanks.. To be honest, most of the radiators are now almost working 100%.. In my unprofessional opinion, I think it may have been a case where they just needed to go through several heating cycles to get "broken in" again after not being used for so long. The main bathroom one (the towel rack one) is also now working 100%.

However, the one in my bedroom (that's the heater in the photos) and the one in my en suite bathroom are now stone cold. Previously, they were heating at the top, but I'm sure by me twisting at valves and whatnot, I've probably turned them off or something 🫠 the pipe at the bottom heats up, but something seems to be stopping the hot water from entering the heater.

I have gas central heating. It's an Ariston, E-Combi One. There are certainly no cylinders in my apartment, and I am not sure if there are cold water storage tanks in the loft (I'm bottom floor with 2 more apts above me).

BarelySentientAI

It'll be the valve in that last photograph.

FreeBear

BarelySentientAI said:

It'll be the valve in that last photograph.

That will be the lockshield - It would normally have a plain cover on it to stop people from fiddling with it.

Lockshields are used to balance all the radiators so that they heat up evenly with the correct temperature drop (usually a 15-20°C difference between flow & return). Do not fiddle with these unless you have thermometers to clip on to the pipes and you know what you are doing.

If you have one or more radiators that are slow to heat up and the TRVs are fully open, the system needs balancing. Having it done properly will help to keep the house warm and improve boiler efficiency.