Pipestats

Zapata123

I think I agree, but in my language
The sequence is asfollows
1return water pipe temp drops and reaches 15 as the garage cools.
2 pipestat contacts made, so that if frostat temp goes downward to 5 there will be continuity from live to demand .
3 temp continues to drop when 5 reached boiler and pump energised, stats in series.
4 water heats up and when 15 on return pipe, pipestat contacts open, so the water temp is limited to 15 max.
5 return pipe water cools and so back to 3 etc etc
Summarising, frostat turns boiler/pump on, pipestat turns them off
I think!!!

Zapata123

I wish I had said it so succinctly

ianto11

You think correct ;);)

Zapata123

Once the pipestat opens contacts at 15C the on to off time will depend on the hysteresis of the pipestat.
I.e open at 15C and close ( to give protection) at say ) at say 13C
Any have any idea what the hysteresis/differential might be

AndyPK

You are very interested by them!

The water will have to cool down first too.

You could set your alarm for 5am, and get up and see if the pipes are warm? :rotfl:


or if going away, take a gas reading before and after to see what has been used. Ensure you right down the red digits

ianto11

Google is your friend, look for your exact make and model, but I believe they tend to range between 4 and 10deg differential

Zapata123

Hi
Thanks for the info Ian

You must be better at Googling than I, maybe I should not have said hysteresis.

I emailed Honeywell Tech support in Bracknell, said pipestat contacts open when when the water temperature rises to 15C, water cools, so at what temperature do the contacts close, to switch boiler on again?
They said my version has a differential of 7 to 10 C, so contacts close when temp is between 8 and 5 C
So the water temperature can vary from 5 to 15C.

If all this is correct, it begs the question what happens if the temperature is set to say 5 and the contacts then close at -5 C?
Mustn’t overthink!
Cheers

ianto11

"so at what temperature do the contacts close, to switch boiler on again? "
The pipestat contacts closing do not "switch" the boiler on again, they merely close part of the circuit to allow the frosttat to. If however when the pipestat contacts close, and the frosttat is not at the required temp, then the system will fire again
I would always have the pipestat set so that the differential drop would still mean that it resets to NC at a higher temp than the frosttat is set.
If your pipestat was set to 5 you would need your frosttat set to -5 to ensure the pipestat had reset and shut the boiler down.
So if your frosttat is set @ 5deg, pipestat min is 15 (allowing for a 10deg differential ) to allow for the proper functioning of the protection.
Hope this makes sense

AndyPK

I would just leave the settings alone!

They sound sensible valves for both protection and economy to me

ianto11

AndyPK wrote: »

I would just leave the settings alone!

They sound sensible valves for both protection and economy to me

I concur