Central heating turning off early

ag19lfc

We have our central heating programmed to come on in the morning for a few hours and then on again in the evening.

It seems to come on and go off again fine in the morning. It also comes on again at the right time in the evening but only seems to stay on for a couple of hours max. It's not switching off because it's reached the set temperature as we have a thermometer in the room where the thermostat is and can see the difference in temperatures when it goes off.

The boiler is only a year old and the fact that it works fine on the morning program would rule out any problems with the boiler.

Would the issue be with the timer unit? It is an old unit (not sure exactly how old as we've only just moved into the house) but the numbers and instructions have faded on it so it looks to be quite old! The red light on the unit is on when the heating goes off, which indicates it hasn't switched off because it thinks the "off" time has passed?

Can we simply go and buy a replacement unit or do you have to be a certain model depending on the make of boiler?

MoneyMate

Timer and boiler information required for recommendations etc for compatibility with you property equipment.

ollski

Probably need a repair to the mid position valve which is usually by your cylinder.

penrhyn

I would have thought its more likely to be interference from a nearby Interrositer.
If not make and model of the boiler timer etc is needed.

ag19lfc

Does the hot water have to be on for the central heating to work? Or should the central heating be able to work independently?

I have had the hot water and central heating set to 'constant' this afternoon and could hear noise coming from the boiler and the radiators were hot. I have just switched both the hot water and central heating to the timer setting and the noise from the boiler stopped and the radiators have now gone cold. Timer is set to go off at 10pm for water and central heating but heating has gone off and it was only 8pm?

ag19lfc

Would the best bet be to call the boiler fitter and get him to take a look at the system?

macman

We can't help unless you post the make and model of your boiler and the programmer.
The heating will go 'off' once the room 'stat or programmer is no longer calling for heat. The timer then overrides that when it shuts it down regardless of room temp.

ollski

It'll still be a motorized valve fault, same as I told you last week :-)

ag19lfc

Thanks ollski

Had a look at the midpoint valve today. I also Googled to see what it should look like:



Having looked at the picture above, I can see that the black switch below the W/M/H is non existent. I guess it's either snapped off or has sunk below the gap that it sticks out of.

How easy is to remove the white casing to see if it's underneath? Or should I get an engineer out to repair it?

ollski

It's just an indicator as to where the valve is water / mid position / heating. Your problem sounds like the motor moves to m or h when you ask for heating but it doesn't make the microswitch to send power to the boiler. When there is a demand for hot water this brings your boiler on and because the valve has moved mechanically your heating comes on too. When hot water reaches temperature it all cuts off.

molerat

Valve motor heads are fairly easy to replace, microswitches, synchron motors and valves are a little more difficult but all can be done by the average DIYer. No disrespect but you seem neither confident or competent to carry out the necessary checks or repairs so it would be best to call out a pro to sort it.