by Longbow archer »
Thu Oct 18, 2007 2:09 pm
Hello everyone.
I know this topic is often repeated on the forum, but after viewing some of the replies, I still have questions as to why my bedroom radiator will not warm up....
Heating system = semi-gravity running off a back boiler (probably around 20 years old), large hot water cylinder, plastic feed and expansion tank. Piping to radiators is larger bore downstairs, smaller bore upstairs. I apologise for the non-technicality here!
Problem: bedroom radiator barely gets warm (this morning I had to switch on the portable fan heater after a pretty cold night).
Firstly, I cannot see any visible leaks (i.e. no puddles of water anywhere in the house). Air gets trapped in the 'problem' radiator all the time. In fact, in order to get the tiniest bit of warmth through it, I have to bleed it. I am doing this every day (with the pump off). The radiator inlet pipe slowly warms but doesn't get anywhere near hot. The outlet pipe stays very cold. Over a period of hours, the radiator only warms very slightly. Sometimes this warmth will tend to be at the bottom of the radiator, at others it will be towards the top.
All of the other radiators are nice and hot (especially so now since a double radiator downstairs has been flushed to remove approximately half a tonne of gunk!) and do not need bleeding. The other two radiators upstairs are fine.
None of the radiators have modern TRVs. Instead they have older simple valves. Two of the radiators (one in the study and the 'problem' one) have identical valves at either end with spindles exposed and no cover to turn in order to open and close the valves. The radiator in the study obviously has the valves open at either end as water is passing through OK and is hot. Could it be that on the 'problem' radiator, the valves are not fully open? N.B. I've already broken the top 1 cm of the spindle on one side!!!
I've checked that the ball in the feed and expansion tank is elevated a few inches above the outlet pipe - all seems to be fine there.
A friend has suggested that I turn all the radiators off that I can and force the system to pump through the study and 'problem' radiators to see if that removes a blockage/airlock. Is this likely to help? Alternatively, could it be that the pump is not turned up high enough (I don't know how to get to it)?
Should I replace all of the valves just in case? Can I establish if one valve is leaking? N.B. At present I do not have any drain valves fitted.
I apologise for the rambling description but have put it all here in the hope that someone out there may be able to offer some advice on what to do next (and before winter sets in!).
Thanks,
Sarah