Ive got a problem in an old Victorian house with some rads not heating up. Im not sure on the model of the boiler but might be able to find out. There are 10 big rads in the house and most have the pipes running from ceiling to floor and back again, with very high ceilings. The upstairs was turned off for a few years but we opened up all the valves and the upstairs gets hot but a couple of the downstairs rads stay cold. We have tried turning the upstairs was down to nearly off but 3 downstairs still stay cold. We emptied the system, vented with copper storage tank, and the 3 rads downstairs got hot while the drain tap was open so water can flow through them. When we refilled the system and bled it water came out every air valve but the 3 rads stayed cold. Does this seem like the pump might not be big enough to cope with 10 rads? The water from the taps is absolutely scalding, will have to check the stat on the tank in case its set to high but it was hot very quickly even with the system being off for quite a while.
Some rads not heating up.
- Thread starter kev25v6
- Start date
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Please note I am an electrician, so others can verify my ideas.
Could the pump be set too low?
Could the cylinder be incorectly balanced, so all the water is pushed around the coil instead of the radiators?
Do you know if the system is gravity? Or fully pumped? Any zone valves?
Could the pump be set too low?
Could the cylinder be incorectly balanced, so all the water is pushed around the coil instead of the radiators?
Do you know if the system is gravity? Or fully pumped? Any zone valves?
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Assuming it must have worked at one time. Only interference being shutting off upstairs, then, quote opening all the valves. I guess could try upping pump speed, but my gut is telling me balancing.
When you drained the system what was the condition of the water that came out
When you drained the system what was the condition of the water that came out
Balancing the rads (as described by the link above) is favourite, to overcome what sounds like a pipe-sizing/flow rate problem. I'm wondering how long you've been in the property and if the upstairs rads have therefore ever been on whilst you've been there? Either way, if the rads were balanced and then all the upstairs rads were turned off, the balance between the rads would obviously have been 'lost'. Turning up the pump, if possible, may improve the situation but risks introducing air into the system, depending how well it was designed. As a last resort, you may need some pipework changed and upsized to happily run the whole system as you desire.
Actually, thinking, or the pump the may be naffed, upstairs getting hot by convection if the boiler is sited downstairs, although this is made more unlikely as the cause if the bottom rads were suddenly cold the 1st time you turned on the upstairs ones. Just a thought.
Actually, thinking, or the pump the may be naffed, upstairs getting hot by convection if the boiler is sited downstairs, although this is made more unlikely as the cause if the bottom rads were suddenly cold the 1st time you turned on the upstairs ones. Just a thought.
The boiler is downstairs and the pump is on 3 upstairs in the airing cupboard. We took off one rad to see if it was blocked or not and it flowed out fine. Hot water came out one of the pipes when disconnected but when hooked back up the rad still didnt get hot. The water was pretty clean that came out.The rads have been in around 40 years with a couple added in the last 10 or so years. It was an old woman who lived in the house and didnt have the upstairs rads on at all and she turned most of the downstairs ones to low to save money.Ive even turned some of the downstairs rads back down hoping to get some heat into the cold ones but to no avail. Its difficult with the valves as they are that old they start to seep when altered and there are soldered bends right next to the valves which make it almost impossible to remove old valves and put in new ones.
The downstairs rads that are cold were cold before the upstairs was turned on but warmed up when the drain valve was opened.The pipework is standard 13mm. Sounds a good system doesnt it?
The downstairs rads that are cold were cold before the upstairs was turned on but warmed up when the drain valve was opened.The pipework is standard 13mm. Sounds a good system doesnt it?
So many unknowns here ;-
10 big rads - dont know if they have ever all worked
Boiler -- dont know make, model or output
To start from scratch, need to know boiler make, model and /or output. Type of system sealed or open vented. Y,W,orS plan.
Then radiator outputs calculated from this :-
http://www.stelrad.com/UK/docs/elite.pdf
10 big rads - dont know if they have ever all worked
Boiler -- dont know make, model or output
To start from scratch, need to know boiler make, model and /or output. Type of system sealed or open vented. Y,W,orS plan.
Then radiator outputs calculated from this :-
http://www.stelrad.com/UK/docs/elite.pdf
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