Radiators hot when cent.heating is not on, but hot water is!

[Ozzie]

Not sure what type of system this is but assume it is not gravity fed as there is a pump. The water in the system is fed by the mains with no means to fill by hand.
Boiler is sitiated behind the fire on ground floor, hot water cylinder is on first floor and has honeywell controls, system is approx 20 yrs old.

On the valve near the boiler there is a slider which says auto at one side and manual at the other end, this is at auto. There is also another 'thing' which has a dial which is numbered 1 to 3, it is set to 2. When turning to 3 it seems to fire the boiler up, is this correct?

Two of the three rads downstairs heat up when the hot water is on, even when the thermostatic valves are turned off. The control radiator upstairs also heats up when hot water is on. A new radiator was fitted recently, the system was drained and then re-filled, this it would seem has caused the system to play up.

Should something extra have been done when the system was re-filled? Why do the radiators heat up even when the rad thermostats are turmed off, why are only some of the rads heating up?

Any help will be much appreciated.

 

[simon]

I would say you have a mix of two problems.The main one being I would say your 3 port motorized valve has gone (the bit with the man/auto slider on).make sure the people who did work on your rads put it back into the auto position.I would guess that the problem with rads heating up when turned off is that you've got directional thermostatic radiator valves which should have been fitted on the flow but have probably been fitted on the return.

 

[Ozzie]

Thanks Simon. The slider was set to auto, not sure they put it to manual when draining the system, does this matter?

The thermostatic valves have been in position for years, some have been replaced but are only a couple of years old, and have always worked fine, and they were ok before the system was drained.

Cheers

 

[simon]

The other possibility is whoever fitted the rad tapped it into the primary return