Why 2 stats in remote boiler house

[Bogart]

After being woken up a few times by clicking pipework when heating not on looked at setup in boilerhouse. Trying to figure out why there are 2 stats in there. One is Honeywell L641B1004 on flow pipe from boiler other is a Honeywell frost stat, model unknown but lowest setting is 5degC, set at 5 degC.
I see no need for boiler to run at temp of 5deg C, yes maybe if around 0-1 degC. Have seen I can get a froststat that goes from -5 to 15 should I replace the Honeywell with one of these. Can someone enlighten me as to what this pipe stat is suppsed to accomplish.
Thanks

 

[Deleted member 120897]

Could it be the that one is for the boiler and the other for pipework? I’ve never had to deal with them, so don’t actually know.

 

[exedon2]

Frost stat puts power to pipestat if below set temperature runs boiler/pump,
When pipestat satisfied shuts off,
Correct honeywell frost stat is
T4360a
I certainly won't recommend setting frost stat to 0° chance of frozen pipework.

 

[Bogart]

Hi
Yes lying in bed last night the penny dropped as to why 2 stats. I will get a replacement frosts stat as I am sure at times the system has run when the temperature has been above 5 deg C which is pointless. To my mind a frost stat shouild do what it says on the box protect from frost. Frost does not occur at 5 degC

 

[Chuck]

To my mind a frost stat shouild do what it says on the box protect from frost. Frost does not occur at 5 degC

The frost-stat does not measure the lowest temperature at every point in the system, it samples the temperature at one place. Also, the sensors used are not exactly precision devices and aren't recalibrated annually. So, taking these observations together, allowing a 5°C margin of error seems prudent and necessary particularly as the consequences of freezing can be quite serious.

 

[Bogart]

On mine the frost stat is monitoring the temperature in a remote boiler house. Agree nopt the utmost in accuracy but what does one expect for £20.

 

[SimonG]

Frost stat kicks boiler in and pipe stat disables frost stat once warm.

Things to look out for. Frost stat screwed directly to stone/brick wall, mount it on a block of wood. Frost stat set too low, frozen pipes. Pipe stat not on return. Pipe stat set too low or too high.

 

[Bogart]

Unsure about pipe stat which pipe is one will check. Frost stat is direct on wall. Is set to minimum of 5deg C