Frost stat and pipe stat issue

wayward64

Hello,
I have a frost stat and pipe stat in my garage and discovered today the pipe stat is 50-90 degrees range .
It was fitted by British gas and every year come and inspect system.
For 5 years now we have been getting big gas bills as the heating turns on in cold weather and seems to stay on.
Due to a plan to change our boiler.A independent gas engineer said we have the wrong pipe stat ,no wonder your getting big bills. He said it should be at 20 degrees and they do 2 models, high and low?
Please can anyone advise if this is correct?

Alex1983

What make pipe stat is it, danfoss is the most common one I see and I think they range from 10c to 90c

Le_Kirk

The idea of a pipe stat is so that your boiler does not stay on for ever. It should be wired such that it breaks the circuit to the boiler (the one that has been initiated by the frost stat) when the temperature of the pipe reaches the temperature set on your stat - in your case 50 - 90. Try turning down the pipe stat to minimum and see what happens. You only want the water in the pipes to be above freezing. Are you sure the wiring is correct?

wayward64

The wiring seems okay and the pipe stat is in series withe frost stat ,The make is a Honeywell one.
its a Honeywell L641B 1012 High Limit Pipe Thermostat,I thought it should be a Honeywell L641B1004 Low Limit Pipe Thermostat..This came from the independent man.H told me the low one is the one include din the kit you can buy for this application. H said most i should set it at is 20degrees on the return pipe which it is.The boiler is in the garage.
Thank you .

jbainbridge

I'm sure I fitted a low limit one years ago. I've set it to the lowest I can get away with. If anything the boiler comes on for 5 minutes every couple of hours (in the garage).

wayward64

Thank you my boiler seems to be on 24/7 at the moment, the programme res being overridden .

jbainbridge

Change it for the low limit pipe stat.

The other thing I do is set the water heating to come on at 10pm every night (during the winter). This puts the 3 way valve in position for water heating ... meaning a shorter time for the return pipe to heat up, and any heating overnight gets stored in the tank. My logic may be misplaced ... but it makes me feel better!

southcoastrgi

Low limit pipe stat fitted on the return pipe

wayward64

Thank you very much for your help, very grateful and sad about all the money and energy wasted over the years.
I will get one and swop it over.

Le_Kirk

jbainbridge wrote: »

The other thing I do is set the water heating to come on at 10pm every night (during the winter). This puts the 3 way valve in position for water heating ... meaning a shorter time for the return pipe to heat up, and any heating overnight gets stored in the tank. My logic may be misplaced ... but it makes me feel better!

Yep, I do the same, although slightly later, my logic being that there is an indirect heating coil in the hot water cylinder that will raise the temperature whereas the water in the radiator pipes will be cool/cold.