Heating upstairs only when on a timer

[davepgt3]

Hi all,

Forgive my lack of knowledge of the subject but I'm a little lost in regards to my heating system and I'm hoping someone will be able to help. I will do my best to explain........

I've just moved into a new house and the previous owner replaced the boiler with a Worcester Greenstar Ri boiler and it's using an old Danfoss FP715 two channel programmer. The programmer is set to auto for the heating and lets say for example I want the heating to come on at 7pm and it does so without a problem, but it only heats the upstairs of the house, the downstairs radiators remain cold. The odd things here is, as it's summer time I wouldn't expect the heating to come on as the thermostat is set to 15 degree's and the house is definitely not that cold. Now, this is the odd bit, if I turn on the heating manually, then all of the radiators in the house, up and down stairs, get hot which makes no sense to me. There's only one thermostat in the house and when manually adjusting it you can hear it 'click' when turning the knob when it gets to the current temp.

For reference, there's no problem with the hot water in the house as that gets heated up fine and when the heating system is manually turned on then every radiator is HOT, so I believe the water must be getting pumped round the system ok.

I do hope this makes sense to someone as I want to make sure I'm not missing something obvious.

Looking forward to getting a reply

Cheers,

Dave

 

[JohnD]

if the room stat is turned lower than the actual temperature of the room, then the heating should not come on, regardless of the timer.

If the upstairs radiators get hot when the room stat is off, then your 3-port valve is probably worn out, and hot water is drifting round when the boiler is turned on for hot water.

Since it seems to work correctly when turned on, it is probably the rubber ball in the valve, not the motorised head.

 

[davepgt3]

Many thanks for the reply JohnD. I just wanted to get an idea of what might be wrong before calling someone out to fix it. I guess it's a big job as the system would need draining, is that right?

 

[JohnD]

it's a common job and not difficult.

It will probably not be necessary to drain the whole thing. If the radiator water appears black and sludgy you could take the opportunity to give it a chemical clean, starting a week or two before draining.

Sludge is not always apparent, though, as it is heavy and sinks to the bottom of the radiators and pipes.

 

[davepgt3]

That's good to hear.......fingers crossed it won't cost a fortune

I'm pleased that I asked as I thought it might have been me being stupid

Cheers,

Dave