Replacing radiator with smaller one

[Keith650]

Hello, I’m new to this forum so hope my question is reasonable. I want to install a new radiator in place of an older wider one in pretty much the same position. The pipework for the old radiator is still in place and shut off even though the old rad was removed years ago. Question is, can I link the new rad up to the existing pipework without having to drain the complete CH system? I realise a bit of plumbing will be needed to fit up to narrower rad but I want to do this, if poss, without having to drain system. Keith

 

[foxhole]

Highly unlikely.

 

[jj4091]

What have they used to isolate the old pipes? But why would you want a smaller one?

 

[Keith650]

Basically, the old radiator was taken away and the valves either side closed - and left closed - 20 years ago. This was because of installing a longer run of cupboards in a small galley kitchen so no longer any room for a wide rad like before. A small electric heater was installed at the other end of the kitchen to make up for it. However, there is still space for a tiny radiator (40cm wide) where the old one was but the pipe work will need to be adjusted. Effectively, the left hand side of new rad would be in same position as previous rad but right hand edge would be further to left now. If could be done without having to drain the whole system then so much the better. Want to do while re-vamping my kitchen. Surely it’s not beyond the wit of man. Or, maybe it is.

 

[Burnerman]

Best tell us what sort of heating system you have, Keith.....combi boiler, for example is no problem, you'll depressurise the system, do the work and then top the boiler up again (with some inhibitor, preferably.)
If you have a vented system with a header tank in the loft then a drain down would help, but for sure there are ways around it!
John

 

[Keith650]

I’m no expert but it’s an old-fashioned system, vented with header tank I’m pretty sure. Oil boiler as I live in the countryside and no gas around here. The boiler is a Grant Vortex, external).

 

[Burnerman]

Yep, almost certain there will be a small (4 gallon) header tank in the loft.
So....you have choices!
1) Tie the ball filler valve up to prevent water entering the header tank. This will necessitate draining out around 4 galls of water before you can crack on.
2) Bung up the outlet pipe of the tank with a rubber bung (or carrot ) which prevents water leaving the tank.....you'll get only a small volume of water escaping as you work.
Now then.....the pipe leading from the tank to the radiator circuit is notorious for blocking up...this makes the radiator system terrible to bleed - or even impossible as the new rad won't fill.
I'd go for (1) but wouldn't be too horrified when the water that comes out is seriously black - at least it gets rid of it!
John

 

[Keith650]

Thank you John. I’ll certainly think about what you’ve told me. All the best, Keith

 

[foxhole]

What’s so bad about draining system and doing a proper job, then you can top up the inhibitor and clear years of sludge .

 

[dontbelieveawordofit]

What’s so bad about draining system and doing a proper job, then you can top up the inhibitor and clear years of sludge .

they’re struggling with pipework for one rad , let alone de-sludging header tanks and fittng new ball balves when the existing fails through messing with it, not to mention removing all the rads for flushing to make your enthusiastic proposal worthwhile.

 

[ericmark]

Using flexible hoses

you should be able to position a new radiator, using a kick space heater it can even go under a kitchen unit, however once you disturb the pipe work your likely to have problems with blockages, so although you could freeze pipes and fit valves and a new heater, but the big question would you want to?

 

[foxhole]

they’re struggling with pipework for one rad , let alone de-sludging header tanks and fittng new ball balves when the existing fails through messing with it, not to mention removing all the rads for flushing to make your enthusiastic proposal worthwhile.

Simple job.

 

[Keith650]

Using flexible hoses

you should be able to position a new radiator, using a kick space heater it can even go under a kitchen unit, however once you disturb the pipe work your likely to have problems with blockages, so although you could freeze pipes and fit valves and a new heater, but the big question would you want to?

Thank you for your reply EricMark and sorry for my belated response. Interested in your flexible hoses option but not too sure how this would work as I would need to be able to connect both ends. Basically, with my old rad gone, there are the two copper pipes left poking out of the floor with the (closed) manual valve on top of each. I guess I was kind of wondering if I could effectively use these old rad valves (left in place and closed) as "isolating" valves while I link up some new copper pipe to them which in turn would connect to to the new more narrow rad via its new valves, and once all connected up, simply open up the old rad (isolating) valves to let the water thru. The new valves would take over control of the rad and the old (isolating) valves simply left open. Question then is: are there fittings available to connect up an old valve (the 25mm thread that used to connect to the actual rad) to 15mm copper pipe instead. Hope you get my drift and I apologise if I've confused the hell out of you ? Keith

 

[Bilabong007]

Rather than flexi hose you could use
https://www.toolstation.com/rigid-radiator-valve-extension/p86447

The do shorter ones and telescopic ones as well

Personally i would lift a floor board and adjust the pipes to come up in the correct place. It looks neater

Hope this helps

 

[Keith650]

Thank you everyone for your replies. I’ve now managed to fit my radiator and it is working just fine with no leaks that I can see. I avoided having to drain down the system by tying up the ballcock in the expansion tank, pushing a wine cork into the vent pipe and stuffing a carrot in the 15mm outlet. When I whipped off the old valves (one at a time) to quickly connect up my pre-prepared pipework, i lost less than a jam jar’s worth of water. Having unblocked my expansion tank again, opened the rad valves and bled it, turned the heating on and checked for leaks, it heated up nicely, as did all the other rads in the house. Checked again this morning, all working fine. I’m a happy bunny. Quite pleased with myself considering I’m not a plumber. Have a super day everyone and thanks for all your replies. Keith