Worcester greenstar 18ri purpose of the CH control knob on face

[warehouseman]

Hi, I have a conventional Greenstar 18ri in a house I rent out. Can anyone explain to me in simple terms the function of the CH control knob on the front of the boiler?
When it was installed, the engineer set the knob at about three quarters way round to the right and said that was about the usual setting, and normally there is no need to touch.......something to do with speed of the flow or the temperature of hot water to the radiators.

Last time I visited I noticed the house was very warm. The girls there have the normal thermostat control in the hall at about 22c or 23c, and also keep on turning the thermo controlled valves on the radiators to max which is annoying. Consequently it gets like a sauna !

If I turned the control knob on the boiler slightly back anti-clockwise, would this have the effect of reducing the temperature of the radiators at all? I may have this wrong, but I am wondering if the hall thermostat clicks off when the 22c temperature is reached but because the radiators are so hot, the temperature still rises for a while afterwards? Also, does the boiler stay on longer, the more the CH knob is turned clockwise?

 

[Best]

I am not gas qualified, but I would think it is the boiler thermostat and it controls the temperature the water to the radiators can reach. That will allow the boiler to run on slightly longer to reach higher temperature if turned clockwise.
I don't want to comment on the partial purpose of speed of heat up and correct temperature setting as some of the gas plumbers on here can advise.
You should really ask your gas service engineer when they next service the boiler - I assume you, as as landlord are having this done, as is legal requirement?
The important thing is the hall wall thermostat and it would normally be set to about 20 to 22 degrees approx in a living area hall on a lower floor for that floor to be very warm. Bedroom areas less heat needed. But it might vary depending on size and variation of rads output and location of any wall stat. Thermostatic radiator valves should only be set to what the max temperature that room requires and not at full setting. If they are turned full up, the room can reach about 29 degrees. But try telling people that! :smile:
Why worry what your tenants do? You are not paying their gas, unless you are renting rooms in your own house, thus using YOUR gas?
So just make sure they know the facts and if everything is safe and serviced regularly, ignore what the occupants decide IMO.
Bit of advice I should add, - get basic instructions and print them of how the heating, including the TRVs are supposed to operate and have them copied and laminated and give a copy to each new group of tenants, so to save endless repeating yourself to people.

 

[gmartine]

Best is far more polite than I am, frankly it's none of your business what temperature your tenants chose to have the heating and TRV's set at. Get a heating engineer in to balance your system properly, you probably have a TRV on the hall rad with the controlling stat.

 

[Heatcarenorwich]

I am not gas qualified, but I would think it is the boiler thermostat and it controls the temperature the water to the radiators can reach. That will allow the boiler to run on slightly longer to reach higher temperature if turned clockwise.
I don't want to comment on the partial purpose of speed of heat up and correct temperature setting as some of the gas plumbers on here can advise.
You should really ask your gas service engineer when they next service the boiler - I assume you, as as landlord are having this done, as is legal requirement?
The important thing is the hall wall thermostat and it would normally be set to about 20 to 22 degrees approx in a living area hall on a lower floor for that floor to be very warm. Bedroom areas less heat needed. But it might vary depending on size and variation of rads output and location of any wall stat. Thermostatic radiator valves should only be set to what the max temperature that room requires and not at full setting. If they are turned full up, the room can reach about 29 degrees. But try telling people that! :smile:
Why worry what your tenants do? You are not paying their gas, unless you are renting rooms in your own house, thus using YOUR gas?
So just make sure they know the facts and if everything is safe and serviced regularly, ignore what the occupants decide IMO.
Bit of advice I should add, - get basic instructions and print them of how the heating, including the TRVs are supposed to operate and have them copied and laminated and give a copy to each new group of tenants, so to save endless repeating yourself to people.

Great help!