Radiator change

[momoosa]

I am wanting to change 2 small single radiators in my house to double radiators as the rooms feel cold even though the rest of the house is warm.

I know radiator size is determined by output etc and it should do the trick but it doesn't so I want to change them.

Under normal circumstances i wouldnt have a problem swapping radiators BUT I don't have a combi-boiler system. I have a boiler in my kitchen and a water tank in the airing cupboard and am not suer how the whole radiator system works.

I think it will be easy enough changing the radiator as you only have to stop the water from the sides (I wont be changing any piping). Can I change the radiators without messing the entire system up? how would i do it?

 

[rebuke]

This should be moved to plumbing, it's not an electrical question, but anyway...

It sounds like you've got a vented system - in your loft you will probably have 2 tanks, one larger one (that feeds the hot water cylinder (which is I assume what you are calling the water tank in the airing cupboard)), and a smaller one - this is a feed and expansion tank for the central heating.

If this is the case, then you are perfectly fine to change it as you suggest - turn off the valves either side of the radiator (if it's a TRV you'll need a decorators cap otherwise the frost stat could still cause it to open), drain the radiator with a little pot underneath it etc, swap it, open the valves to the new one, and open the bleed valve to let the air out until water appears. The extra water required will come from the F+E tank in the loft, which should have a ballcock valve on it to refill it...

 

[ericmark]

Cheat and paint the radiator mat black. Black radiators heat better than white look at any radiator not on view like the one in your car or inside a myson type radiator they are always mat black.
The college I attended science department decided to get all radiators painted black as it was best colour but at that time there were no TRV's and the area got far too hot as it upset the balance and they had to be painted white again.
Eric

 

[momoosa]

Thanks for that peeps but your dealing with a humble DIY novice. What's a TRV??

 

[ericmark]

A TRV is a thermostatic radiator valve most have two sections the chromed brass valve which has a pin sticking out off it with threads on outside to which is screwed a plastic vented lump which can be turned to regulate the temperature. Although screwing this down to lowest setting may stop the water flow should the room cool down it can automatic turn on again. The knurled chromed ring that holds on the plastic lump can be unscrewed and a plastic cap screwed on instead this will force down the pin and shut off water flow without being temperature dependent and should be fitted before radiator removal.
Older system just have two taps. One with a cover called a lock shield valve which is set to get a temperature differential of 10 to 20 degrees across the radiator and tap with a user operated valve with knob on. both really same valve just one with cap on and other which knob on these are no problem you just turn off. See http://www.screwfix.com/sfd/i/cat/82/p4761682_x.jpg for a picture of a TRV.
Eric