Central heating turning on by itself

keith969

gas4you wrote: »

Never known an Ideal boiler to have frost protection as yet.

This sounds more like a stuck zone valve. You will either have 2 x 2 port valves or 1 x 3 port valve.

Could be just the microswitch in the acuator head has broken and stuck on.

It is these valves that tell the boiler to come on, not the programmer or thermostats.

Huh? A zone valve is controlled by the programmer, it doesn't tell the boiler when to turn on/off, the programmer and thermostats do. Sounds more like the programmer is faulty.

slipthru

keith969 wrote: »

Huh? A zone valve is controlled by the programmer, it doesn't tell the boiler when to turn on/off, the programmer and thermostats do. Sounds more like the programmer is faulty.

The programmer has just switched on but the thermostat is switched right down but the heating has come on?

Forgot to add that if I turn the water off on the programmer that heating goes of too until I turn the thermostat up.

keith969

slipthru wrote: »

The programmer has just switched on but the thermostat is switched right down but the heating has come on?

Forgot to add that if I turn the water off on the programmer that heating goes of too until I turn the thermostat up.

Which thermostat? The room one, one on the hot water tank or what? And what do you have the programmer set to - HW only, HW+CH, or off ?

If the programmer is set to HW only and the room thermostat turned right down but the rads still get warm, then it could be a stuck diverter valve.

If you turn the programmer to off (neither CH or HW) and the boiler still comes on when you turn the room thermostat up, then it implies the programmer is faulty.

slipthru

The heating (and hot water I assume) come on randomly at night when the the programmer is set to off for both and the room thermostat which is situated in the hall is turned right down. When this happens a ticking noise starts in the airing cupboard. as far as i can tell it only happens when the valve is in the mid position.

Yesterday for the first time the central heating stayed on after the timer had turned itself off. I have checked today and if I turn the thermostat up in the hall the heating comes on without the timer being switched on.

keith969

Well it does sound like your programmer is faulty. You can probably replace this yourself, what make is it?

Just being pedantic, but what you refer to as a programmer and a timer are one and the same thing, right?

slipthru

Yes i am talking about the the same thing, It's a lifestyle Lp112.

I have just put the hot water on and turned the heating off on the timer and the heating is also on. I just checked the mid port valve actuator and it is in the middle although it is not ticking for once.

I thought it would be in w postion for hot water only.

gas4you

The programmer and room thermostat control the 3 port valve.

When the motor moves to allow ch, the microswitch is made to tell the boiler to fire.

The power for the boiler when on HW comes from the cylinder stat.

Basic stuff for those who know.

Faulty valve or valve head.

£125 is good to supply and fit a new one. These Drayton ones are less reliable and more expensive than others.