Inherited system another anomaly!

[Bogart]

The more I investigate the system I have inherited I wonder who was employed to maintain it?
A couple of meters along the boiler output point is a pipe stat. A Honeywell L641B1004 which has a range of 10 to 40˚C, . I think what should have been installed is a L641B1012 which has a range of 50 to 95˚C. There is a frost stat nearby so assuming not meant to be another frost stat

 

[ShaunCorbs]

What does the boiler supply/ heat ?

 

[Bogart]

Very old Camry 5 supplying rads and hw via normal tank in loft setup.

 

[ShaunCorbs]

Is there any tees before the stat ?

 

[Bogart]

Nothing at all leaves the boiler in 28mm stat is positioned about 75mm after a 90deg elbow which as mentioned before is about 2m from the boiler outlet.

 

[ShaunCorbs]

Do you know if the stat is controlling the pump ?

 

[Frog67]

Sounds like the correct pipe stat as it needs to be set at 25 C. Only thing is it should be on the return and within 600mm of boiler

 

[Bogart]

Do you know if the stat is controlling the pump ?

Will have a look tomorrow.

 

[Bogart]

Sounds like the correct pipe stat as it needs to be set at 25 C. Only thing is it should be on the return and within 600mm of boiler

Can I ask why it should be set to 25˚C?

 

[Bogart]

Checked and found both are operating as frost stats. If either are switched on the boiler comes on but not the pump! All seems a bit odd as the two stats are literally a foot apart. So much for my theory that the pipe stat was an overtemp device.