Newly Added Radiator won't get hot

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Hello, I have installed a new radiator into my central Heating system and it won't get hot. The system is a 6 rad plus 1 new, Alpha new combi boiler in a concrete doorstairs floored 3 bed semi house with all the pipes going under the upstairs floorboards and going down and up to each radiator in each room. The system uses seperate 22mm flow and return pipes which have seperate flow and return 15mm pipes connecting the raditors in each room. The exception is the new radiator which has been connected to the existing bathrooms 15mm flow and return pipes and extended downstairs to the new radiator in the corner of the kitchen.

I have tried bleeding all the radiators, seperately and just the new rad, tried switching off all the valves apart from the new rad, tried fitting a one way flow valve in the new rad pipes in both directions (to try and direct the flow to the new rad). Checked the new rad for blockages using a hose to wash it out, tried numerous valves on both ends of the rad and open closed them. The new rad won't get hot at all and the water will not flow around it. When you fill the system it will go to the new rad no problem but the water will not circulate or get hot. The pipes supplying the new rad don't get hot either and the connected pipes which come off the bathroom radiator going down to the new rad only get slightly hot for about 12 inches along the flow and return pipes. I have tried switching off the supplying bathroom radiator but the water will still not flow to the new rad in the kitchen at all.

Had to put the flooring back down in the bathroom to finish off bathroom at Xmas and left the new rad as it was as was under threat of death from wife if bathroom wasn't tidied but now got to sort it out whilst weather warm.

Any hints or suggestions welcome. I was gonna try connecting new rad pipes straight to 22mm main flow and return pipes but now I think this won't make any difference as when you close the bathroom rads valves it still won't get hot.

Thanks

Tony
 
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If it really does not get hot with all other rads turned off then it seems serious problem.

Why not do the bucket test? See FAQ on this site.

Tony
 
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Is it possible that you've accidentally teed both feeds from the flow or both from the return? Unlikely but I've heard of it done before and that would explain water at rad but no circulation.
 
I was going to suggest
A. Check you haven't teed off the same pipe, either flow or return (as DaleRCL has suggested).
B. Shut all the other rads.
C. Check that lockshield is open and TRV pin not stuck closed on new rad.
 
Is it possible that you've accidentally teed both feeds from the flow or both from the return? Unlikely but I've heard of it done before and that would explain water at rad but no circulation.
I traced the two 15mm feed and returns to the bathroom rad and checked where these two feeds came from to make sure it wasn't connected wrong way round ie flow to feed and return to flow. I traced them to the main 22mm pipes and they are from diff pipes not the same.
 
If it really does not get hot with all other rads turned off then it seems serious problem.

Why not do the bucket test? See FAQ on this site.

Tony
Not tried bucket test yet but have flushed rad - this is one thing I should try first
 
What do you think of going straight from 22mm pipes to new rad ? Would this make any difference ? It might have more pressure than from the 15mm rad extensions ?
 
tried fitting a one way flow valve in the new rad pipes in both directions
Tony
What do you "mean in both directions"?. Whatever the snswer, take them off again - they are more likely to get blocked in time than help the situation.
As I read the OP, my immediate thought was teeing off the same pipe. Are you SURE you gave a flow and a return?
Other 2 options are a physcial blockage or air - could be a lump of wire wool or even sabotage at the merchants. If you pushed pipe along under the boards you can pick up garbage. Does the pipework have a high point?
 
What do you think of going straight from 22mm pipes to new rad ?
Should not be neccessary

Water seems to flow in new 15mm pipes so must be getting through.

Filling a circuit is not the same as circulating. You can fill through a partial blockage, but the resitance will be too great to circulate. Hence Dan's obseration and my suggestions.
 
Ok, stupid question time but here goes. Is the bleed valve blocked or faulty? Have you tried removing it? (I'm not sure from your original post whether you managed to actually fill the rad).
 

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