Boiler Intermittently Firing Up

[Kermit]

Hi

Firstly thanks for reading this. We have recently purchased our first house and I have a question regarding my boilers "activities" .

Below is a list of components (which reading some of the other post will mean a lot more to someone - unlike me)

Boiler (Installed in the Garage)
- Ideal Classic NF250
- Burner switch = ON
- Thermostat Knob = 4.5
- On the bottom I can see VR4601E A1024 (not sure if this is of any use)

Near the boiler (Top)
- Honeywell Frost stat
- Honeywell L64/B/004 - Set to 5 degrees celsius

Thermostat (Hallway)
- ACL Drayton
- Set to 21.5

Controller (?? - not sure if this is the correct terminology - Kitchen)
- Drayton Tempus Three
- Water and Heating configured to come on 6:00 - 7:50am and 6:00 - 7:30pm

Now to my question. I will be sat at home or even in bed late at night and I can hear the boiler fire up (normally outside of these times - 6:00 - 7:50am and 6:00 - 7:30pm). Originally I thought it was something to do with the frost stat but I'm convinced it has done it on slightly warmer days. Again I'm not sure how such systems should work but is it possible to tell me how and why this would happen - my main concern is the gas bill

Any info or comments are appreciated.

Regards,

Dave

 

[chrishutt]

Almost certainly the frost stat. That's what they're supposed to do, to protect the system, especially in unheated spaces like the garage, from freezing. You could try turning the frost stat down a tiny bit, but not too low. Otherwise you could fit a pipe stat to work in conjunction with the frost stat so that once the return water reached a certain temperature the boiler would cut out.