One rad not hot
Discussion
Oldish system (maybe 40yrs) but reliable (one pump req in the last 14yrs)
All seems okay but one rad in a downstairs extension (a cold room at best) does not heat up very well. I took the rad off and flushed with a hose loads of manky water came out. Seems to have improved it a bit but still not as hot as the others.
Would a simple flush sort this out do you think? or should I call a heating engineer?
All seems okay but one rad in a downstairs extension (a cold room at best) does not heat up very well. I took the rad off and flushed with a hose loads of manky water came out. Seems to have improved it a bit but still not as hot as the others.
Would a simple flush sort this out do you think? or should I call a heating engineer?
Try shutting off all the other radiators in the house so that only the problematic one is open. This may help clear any blockage. Also if this radiator now does get nice and hot it will prove that the water flow to it is not restricted. If that is the case then your system may need balancing so that the other radiators are not starving this one of hot water.
Hmm. Rad in extension usually = badly plumbed in by a muppet.
Few things to try,
Bleed it, with the heating switched off (running the pump while bleeding can draw air in).
Take a note of how far open the lockshield valve is. Open it some more. (keep a note, so you can put it back as-was). You may find that the system needs balancing, especially if you notice that all the valves are wide-open on all the rads.
If it has a thermostat valve, take the head off and check the pin on the head of the valve moves freely.
A thing to try would be to shut down the valves on all the other radiators, and open the valves on that one radiator fully. Does it get hot then?
Few things to try,
Bleed it, with the heating switched off (running the pump while bleeding can draw air in).
Take a note of how far open the lockshield valve is. Open it some more. (keep a note, so you can put it back as-was). You may find that the system needs balancing, especially if you notice that all the valves are wide-open on all the rads.
If it has a thermostat valve, take the head off and check the pin on the head of the valve moves freely.
A thing to try would be to shut down the valves on all the other radiators, and open the valves on that one radiator fully. Does it get hot then?
I bled it the other day when i put the rad back on. I've shut off the other rads and running boiler full blast and the rad is now very hot. Does this point to a blockage or balance the system? I used to have (many yrs ago) some rad thermometers for this but can't find them anywhere now.
It could have been plumbed by a muppet, it's never been that good we've been 12yrs.
It could have been plumbed by a muppet, it's never been that good we've been 12yrs.
Is the rad plumbed off the ring?
I was round a friends and he was complaining of rad problems in the extension and it turned out the DIY'ing previous owner had plumbed the new rad in series with the existing/adjoining dining room. This meant that the flow to the extension was controlled by a thermostatic valve in a warmer room.
Doh
I was round a friends and he was complaining of rad problems in the extension and it turned out the DIY'ing previous owner had plumbed the new rad in series with the existing/adjoining dining room. This meant that the flow to the extension was controlled by a thermostatic valve in a warmer room.
Doh
Basically as previous posters suggest the rad has been teed off. This can mean the hot water is flowing past the tee and as the more circular loop is forcing the cold out. What you need to do is balance the rads so that a slower flow allows the water to seep into the tee and through the circuit created by the new rad. Ideally an extension should tap into an existing manifold rather than directly into the circuit.
Sometimes it's simply an airlock in the pipework. Shutting off other rads concentrates the entire force of the pump around that section of pipework, which is now powerful enough to shift the airlock.
But, if the existing system is very old, there is a chance that it is a one pipe system. Adding a rad on to these systems is problematic and rarely work effectively.
But, if the existing system is very old, there is a chance that it is a one pipe system. Adding a rad on to these systems is problematic and rarely work effectively.
OldBuoy said:
Does this point to a blockage or balance the system?
Balancing I reckon.As mentioned, that rad could be plumbed badly which makes life harder to get it right. If the rest of the system seems fine, double the amount the lockshield is open on that one rad and see how that goes. If it's full open and still rubbish, other rads will need to be closed-down a bit.
Loads of info out there on balancing, I won't rewrite them except to say take notes as you start, and every change you make. Very easy to lose count.
I'm sure lidl\aldi had an infrared thermometer on offer the other day.
Well balanced them up, and all the rads seem better and the cool one is warming up.
One rad still gets b
d hot, the lock shield valve is seized and I managed to shear the top of the spindle off trying to free it. 
So trying to regulate tht one by turning down the TRV.
Thanks for you're help and advice.
One rad still gets b
d hot, the lock shield valve is seized and I managed to shear the top of the spindle off trying to free it. So trying to regulate tht one by turning down the TRV.Thanks for you're help and advice.
Edited by PositronicRay on Sunday 26th October 07:24
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