Radiators are not hot

Kaldo

Hi all,

I've gas heating at home. Boiler thermostat is on 5 (being 6 max) plus room thermostat over 25 ºC however we don't feel warming enough. If we increase the room temperature, the radiators don't get hotter.

What do you suggest the issue could be?

Thanks

Wearb

Is the radiator too hot to keep your hand on, top and bottom?

Kaldo

No, never too hot top and bottom. They are fully open (checked and re-checked...)

Wearb

Turn off all rads except 2 and see if it improves.

Do you have a hotwater cylinder? If yes, you might post a pic of it and attached pipework.

Kaldo

I did it and didn't improve.

Yes, I do have a hotwater cylinder with 2 zoned motorized valves for radiatiors located upstairs and downstairs plus another for hot tap water.

I noticed that the heater from the boiler turns off after 6 minutes of working without the temperature reaching the supposed to reach based on the room thermostats. The heater works but stops working after a few minutes.

Why?

DGOBS

Sounds like you may have very poor circulation.

In this case, as the circulation is restricted, the boiler actually reaches temperature quickly as is cannot get the hot water away and around you system.

Primary causes:
Poor circulating pump performance (may need a new pump)
Scaled up boiler heatexchanger (may need at least a new hex, and possibly a power flush)
Sludged/scaled heating system (may need a power flush)

One last one, is just in case the boiler is a Baxi Solo, it maybe a gas valve issue.

You will really need to engage a good RGI plumber to come out and diagnose for you.

Kaldo

I got the boiler service back in March

DGOBS

Regardless, pump and gas valve are mechanical issues that can happen anytime, regardless of service (they are non serviceable components)
Plus on the scale and mechanical side, a lot can happen in 6 months.

Kaldo

Thank you.

Kaldo

It seems there is an issue with the gas valve. Now what's the normal cost for a gas valve's replacement? Better to change the whole boiler?