Just checking my understanding of frost stats..
My customer has a boiler in a garage (12year old Vaillant/British Gas boiler on an unvented system), with an external frost stat wired in (not a pipe stat, but a 'room stat' from 0 to 10c).
If the ambient temperature drops below the set point (say 5c), could the boiler potentially be running continually (until the air temperature rises back up again)? The boiler wouldn't kick in (as the programmer wouldn't have kicked in). Zone valves to HW and CW would be closed. But reverse circulation could heat up the rads and cylinder, depending how long the boiler was running for.
Or would the boiler PCB know it's connected to a frost stat, and so to switch off when the boiler water return temp reaches 20c (or thereabouts)?
When I'm there (daytime) and warmer evenings, no reports of the boiler coming on. But I thought I'd recommend a new frost stat, just to be sure the current one (which is fairly old) hasn't lost its calibration and is coming on at too high a temperature.
My customer has a boiler in a garage (12year old Vaillant/British Gas boiler on an unvented system), with an external frost stat wired in (not a pipe stat, but a 'room stat' from 0 to 10c).
If the ambient temperature drops below the set point (say 5c), could the boiler potentially be running continually (until the air temperature rises back up again)? The boiler wouldn't kick in (as the programmer wouldn't have kicked in). Zone valves to HW and CW would be closed. But reverse circulation could heat up the rads and cylinder, depending how long the boiler was running for.
Or would the boiler PCB know it's connected to a frost stat, and so to switch off when the boiler water return temp reaches 20c (or thereabouts)?
When I'm there (daytime) and warmer evenings, no reports of the boiler coming on. But I thought I'd recommend a new frost stat, just to be sure the current one (which is fairly old) hasn't lost its calibration and is coming on at too high a temperature.