central heating turns itself on

[minstralpiper]

In summer have only hot water turned on at the programmer.Every now and then central heating turns itself on.Both lights are at the programmer.If I turn off power to programmer and then back on again it sets itself. Any idea where fault lies.

 

[londonboy]

You say both lights (hw and heating) come on at programmer on its own?

Faulty programmer, or
Incorrectly set (!)

What model is the existing programmer?

 

[minstralpiper]

Programmer is a Drayton LP 522
The programmer is new as thought old one was faulty but same problem exists. For summer use only water is on and the timer comes on and off at the correct times. Every now and then when the timer cuts in at about six in the morning the heating comes on as well. To cancel it I have to switch off the power to the programmer and then switch back on again. The programmer then acts fine for a few more days switching on and off correctly until the heating again comes on and I have to go through the same process.

 

[londonboy]

Well if the heating is coming on at the programmer of its own accord then I can only suggest programmer.

If the heating is coming on without the programmer then it's another issue.

Hang on, just a thought. The 522 is a 5/2 timer, are you sure its set correctly at the weekend??

 

[Agile]

The Drayton programmers are very reliable.
The indicators are probably powered by mains on the outputs.

If thats the case then another faulty component could backfeed a voltage to the programmer causing the lights to illuminate.

Tony

 

[matt1e]

The Drayton programmers are very reliable.
The indicators are probably powered by mains on the outputs.

If thats the case then another faulty component could backfeed a voltage to the programmer causing the lights to illuminate.

Tony

agreed! especially if as you say the old programmer was doing the same
what make is the boiler?
do you have a frost stat?

 

[WDIK]

external motorised valve micro switch

 

[doitall]

Micro switch sticking in the MV as WDIK has said.

Change the actuator and all will be fine.