Boiler thermostat?

[ChrisSA]

Hi,

We have an S-plan system. TRVs on all rads & no room stat. Cylinder has a stat (set for 65 C ish).

Sometimes when cylinder at temp (or sometimes when HW off, and CH only on), the boiler will turn off. I thought it would run permanently as there is no room stat.

Is this the Boiler stat reaching setpoint and turning the flames off?

Thanks

 

[Rob]

Yes.

And get a room stat. It's more efficient.

 

[D_Hailsham]

We have an S-plan system. TRVs on all rads & no room stat. Cylinder has a stat (set for 65 C ish).

An S-plan has two motorized vales, for hot water and heating. They are controlled by thermostats. If you only have a stat on the HW cylinder, how is the CH valve controlled?

The cylinder stat only needs to be at 60°C; anything higher is just wasteful.

 

[ChrisSA]

We have an S-plan system. TRVs on all rads & no room stat. Cylinder has a stat (set for 65 C ish).

An S-plan has two motorized vales, for hot water and heating. They are controlled by thermostats. If you only have a stat on the HW cylinder, how is the CH valve controlled?

That was my question. In the absence of a room stat (room stat connection block is linked out), what is causing the boiler to turn off (in a situation where HW is off or not being called for)? Is it the boiler stat?

I'm planning on fitting a CM927 in the lounge (setting the 2 lounge TRVs to max). I'll also get someone round in the summer to fit an auto bypass valve (replace the 15mm gate valve) & drain/refill/balance the system. I'll use that opportunity to renew all TRVs and replace the lounge ones for normal valves.

 

[jimhowert]

also if the hot water cylinder stat is set at over 65degrees C then limescale will accumulate!

 

[namsag]

Yes boiler stat turning boiler off