installing a larger radiator Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[steev999]

hi all and a happy new year to everyone.
i am new to this forum and would like some advice on installing a larger radiator (500 x 800, replacing 450 x 400) in an en suite shower room. i have a limited understanding of ch matters!
i was wondering if it was possible to isolate and drain off only the radiator i want to replace rather than draining down the full system, and therefore have to refill and add the inhibitor?
i have the amptec 12kw electric boiler, which works fine, its split into ground floor and first floor zones. and has a red filling tank attached, we have knocked the en suite through into part of one of the bedrooms, doubling its size, so need to increase the radiator. i obviously have to extend one side of the pipework, as the rad will sit in the same place as the old one, so one side will be fine and need no alteration.
i think i will probably have to drain the sytem, so any advice how to do this will be gratefully received, as i hear of horror stories of not being able to get the system to work due to vacuums etc. etc.!!!
many thanks
steev

[htg engineer]

You will need to drain at least the upstairs radiators, this can be done by using a drain point on or near the boiler, or one of the downstairs radiators, are there any drain taps on the downstairs radiator valves/pipework ?

If there's no drain points you may want to think about adding one for future work.

It's always best to add new inhibitor if you drain the system down, as you don't know how much - if any - is left in the system.

Why not fit the radiator valve to one end of the new radiator, and make sure it's closed. Add the inhibitor to the radiator then fit the other valve (closed) when you fill the system and open the radiator valves the inhibitor will be in the system.

It's a pressurised sytem so should have no problems with airlocks.

[steev999]

thanks for the speedy reply htg engineer, that sounds like a good idea to me, there are lots of drain of taps around the house, every single radiator has one!! which is the easiest to use? the one on the radiator that i am changing, or any other? and will i get away with draining the upstairs only? how do i stop the system refilling up, which stop cock needs turning off? what type of inhibitor do you recommend for my system?
sorry so many questions!!!!
thanks in anticipation!!

steev

[htg engineer]

If it is - and I'm sure it is, a pressurised system - you wont need to turn off any isolation taps as the sytem will not refill until you repressurise the system at the boiler (red filling tank) ?

As i'm not sure of the set up of your system I can only offer advice - a little bit knowledge of how your system is piped would make it easier for you.

Turn the heating on - to all zones. This will make sure all zone valves are open. Then I would drain the system using one of the drain points on one of the downstairs radiators, This will ensure all upstairs radiators and pipework are empty. To drain open the drainoff and attach hose, after 5 mins or so open the vents on the upstairs radiators, you should hear air being drawn in. When the water stops running out of the hose you know it's empty.

This will drain all the upstairs radiators and pipework, if the system has been piped where - the pipes for downstairs radiators come from upstairs - If the pipes for the downstairs radiators come up from the floor, then it may drop a little from the downstairs radiators - but not fully as you haven't opened the radiator vents. This doesn't matter - will just need bleeding when refilling the system.

Use Sentinel x100 inhibitor

Hope this helps