Diagnose my central heating
Boiler running fine and HW production fine also, but nearly all the radiatiors are not really heating up and then only at the top and are cold at the bottom.Posted 4 years ago
Another thing I’ve noticed is that the radiator in my bedroom used to make lttle pinging noises as soon as the heating came on which I thought was due to the increased pressure from the pump – this doesn’t happen now.
My feeling is that the pump is pooped – any other suggestions other than bad CH Aids? Pump is a Gundfos and is about 10 years old.
Any checks I can carry out?
You can hear a pump running and feel it vibrate if you touch it. If you’re comfortable using a multi-meter you could just see if it is drawing current (although if you’re not happy with live mains I wouldn’t try this at home kids).
Another symptom of a dead pump is the boiler short cycling, firing up then shutting off every few minutes as the heat isn’t taken away quick enough and the heat exchanger hits cut off temp too quickly.Posted 4 years ago
Another symptom of a dead pump is the boiler short cycling, firing up then shutting off every few minutes as the heat isn’t taken away quick enough and the heat exchanger hits cut off temp too quickly
I should add that it’s a very old boiler that is way too dumb to do something like this!
There is ‘some’ vibration when the heating is on.
The only other thing I can think of is that the pipework is blocked somehow. A flush seems fairly pricey though.Posted 4 years agowobbliscottMember
your pump circulates water through both the radiator circuit and the hot water circuit, so if you’ve got hot water then you’re pump cannot be goosed. It is most liktly to be your motorised valve as this is the valve that diverts hot water from your boiler to your hot water circuit or your radiator circuit or both.Posted 4 years agomartinhutchSubscriber
Sludgefest, possibly, but if it’s a sudden change, an obstruction or a part-malfunctioning valve is more likely.
Do you have TRVs on the rads? Try shutting off all the rads but one, and opening that valve right up to give it the full force for a bit. If your pump has a higher setting you could give that a shot at the same time.Posted 4 years agotrail_ratMember
does your system have inhibitor in – and has it always had inhibitor in ?
id be tempted to drop the water – take an affected radiator into the garden and give it a flush with the hose if the TRV trick doesnt work. easy check for broken TRVS – are the inlet pipes hot and rad cold or the whole lot – if the whole lots cold id be thinking blockage/valve or airlock but if the inlet pipes hot and the rads cold id think sticking TRVPosted 4 years agocrofts2007Member
Nobody has mentioned balancing the radiator system yet.Posted 4 years ago
May be that the flow through them is too fast.
Back the outlet valve right off to closed then open to about 1 to 2 turns, the water will then flow through slower and give up? its heat to the radiator/room.
Worth a try, but thinking back it does sound like sludging in the radiators.
If the boiler is an old cast iron heat exchanger then more likely to be iron deposits/sludge in the rads if a decent/any inhibitor has not been used.
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