Central heating frost stat

[bikeit]

Our oil central heating system has the boiler outside inside a small purpose made unit, there is a frost stat fitted inside the unit.
Am i right to think that the frost stat is supposed to turn on the boiler so that it does not freeze in the winter, but it never seems to work.
How can i check this to see if there is power going to it or check to see if the stat is faulty.
Any help would be great.

 

[EFLImpudence]

You are correct in the reasoning.

However, I presume your boiler has not frozen and would be on in the cold weather so how do you know it doesn't work?

To test you will need a two-pole voltage detector or you could make a test lamp.

 

[holmslaw]

..

 

[bikeit]

EFLImpudence last winter the temperature here was as low as -17, and overnight or at times when the heating was not on the frost stat never once switched on the boiler.

holmslaw i turned the stat up and nothing,

 

[EFLImpudence]

Seems as if you need a new one or there is a wiring fault.

If you can't test for voltage and continuity yourself you will need an electrician.
Not a huge job.

 

[bikeit]

Am i right in thinking there will be three wires inside the surface mounted box that holds the stat? if so and there is power going to the live wire its a new stat i will need to get.

 

[xr4x4]

EFLImpudence last winter the temperature here was as low as -17, and overnight or at times when the heating was not on the frost stat never once switched on the boiler.

holmslaw i turned the stat up and nothing,

Wait until it's colder, I.e at night and turn it up, it should 'click' when it gets to the temperature the air is.

If it doesnt, it's broken, if it does and the boiler doesn't fire up, it's a wiring fault.

 

[EFLImpudence]

Am i right in thinking there will be three wires inside the surface mounted box that holds the stat?

Possibly - may only be two.

if so and there is power going to the live wire its a new stat i will need to get.

If there is power to it you will then need to ensure that when it is switched on power come out the other side and goes to where it should.