boiler working but no central heating

Hello,

My gas central heating has been working intermittently for a while and has now stopped working completely.

I checked the boiler and the pilot light is on so i am guessing it is not that.
Also when i turn it on i can hear the pump start and keep going but no heat is making it to the radiators.

The water is hot, but maybe that is because there is a water heater switch in the airing cupboard with the tank?

Like i said, it has been playing up for a while. Previously when i turned it on at the control panel everything would start up but no heat to the radiator. I would then turn it off at the main switch and on again and then it would work fine and radiators got hot. Now i cant get it to work this way.

I'm assuming as the radiators heated up properly before that it isn't a case that they need bleeding.

Any ideas or is it a maintenance call out?

Thanks for any help

Do you have a 3port mid position valve in the pipework just after the pump.
These sometimes give problems, when the valve won't move away from the HW position.
Or do you have two 2port valves one for HW and one for CH.

Hello,

Thanks for your reply.

I am currently at work but i will check when home tonight.

so basically i am looking to see if it splits off into 2 or 3 pipes?

i know i have hot water and heating separate switches on the control.

Thinking this maybe a job for a professional!

A 3port valve will have one pipe going in underneath coming from from pump and one pipe coming out on each side of the valve. One for HW and one for CH. (forming a T ) Or two separate 2port valves ie in/out for HW and in/out for CH.

from what i can see there is only one pipe going into the pump from underneath. Only one comes out above but then splits into 2 bits. One goes into the cylinder and one loops around and goes underneath the airing cupboard floor.

I gave the pump a bit of a bang and now the heating is working again pretty well but not quite as hot as it should be...

I take it it splits into two bits at a Tee junction and not through any valve then.
So both HW and CH are pumped.
Water will take the route of least resistance so it would rather go through the cylinder heating coil than through all your radiators. Sometimes a bog standard gate valve is fitted where the heating coil leaves the cylinder.
By adjusting this valve, the resistance through the coil can be increased, which means more water will go through the heating side.
Also pumps can be a bit misleading. I removed a friends recently for examination to find silt had formed around the inlet and outlet ports. The 20mm diameter ports were reduced to about 7mm, which explained why water was not able to reach the radiator furtherest away.

hello,

i've uploaded 2 pictures in an album . The red one is what i 'm assuming is the pump.

The blue one attached in a different place to the tank that says 'pump actuator' on it. It has an 'a and b' switch on the side.


The red one has a bit on the side which when turned makes it go faster. So a couple of different speed settings i guess.

Also there is a sort of screw to turn it with arrows either way. I says 15 - 60 on the side.

These are the only adjustable bits on these.

Sounds like its going to be a call out. Do you know roughly how much something like this might cost?

The pump is the red one. A 15-60 equates to 6 metre head, a 15-50 equates to 5 metres head. 15-60 £85 and 15_50 £75 at screwfix. B & Q dearer by £10.

There are cheaper pumps around, but Grundfos are the best
Sounds as though your pump was stuck.
Maybe worth removing to check internal condition.
If your rooms are not warm enough, you can adjust the flow through radiators by adjusting the lockshield valves

The blue component is a motorised valve. Can't see the pipework, but presume one pipe in and one pipe out (2port). Seems to control the water flowing into hot water cylinder only.