Replacing radiator on a Megaflow System

paragp

Hello

I need to replace a leaking (from the center and not from the valves) radiator in my house. It is connected to a Megaflow heating tank.
I also want to add some inhibitor to the system.

Questions:
1. To drain the radiators, is it just a case of closing the mains cold water stopcock and then opening the drain valve from the lowest radiator in the house?

2. How can I add the inhibitor to the system?

Any help would be greatly appreciated.

thank you

nofoollikeold

If the radiator you want to replace is already leaking, I'd suggest:

a. Shut off both radiator valves.
b. Let water drain out of leak until it stops.
c. If leak is at base of radiator, that should be enough.
d. If leak above base of radiator, slacken connection between one valve and radiator, drain remaining water.
e. Check no further water coming out.
f. Fit new radiator to old valves.
g. Open valves, bleed new radiator.

The above won't work if:

i) New and old radiators different sizes
ii) New and old radiators have different types of valve.
iii) You can't fully shut off flow with radiator valves.

If it won't work, would need to know more about your central heating (no hot water) system. Type of boiler, sealed or open vented system.

Alias_Omega

Naturally it is easier to get the same size, same brand of radiator and swap like-for-like. Sometimes when this cannot be done, you may need to re-drill the wall for new mounting brackets etc..

Oh the joys..

paragp

thanks guys for your replies..

So on saturday I did what nofoollikeold suggested, stopped the valves, drained the radiator and took it of. The brackets were not right so had to take old ones off and drill for new ones.

all done.

The system is an unvented (i think). basically i have a potterton suprima 120L boiler, a megaflow tank in the loft, not separate expansion tank, the air in the tank needs to be recharged every 6mths.
There is a small tank blank open tank connected to the megaflow tank.. so not sure if this is called a open unvented system.

Now I need to add the sentinel inhibitor but not sure where to add this within the system.. I did try to put it in directly into the new radiator using a funnel connected to a bit if hosepipe but this did not work.

hope the above made sense

thanks

alan.t

confusing about the cylinder tank bit, but easiest way to put inhibitor into an existing system is the new style canister which inject it into any radiator, should cost you about £20 from a plumbers merchant but save a heck of a lot of hassle, best in my opinion is Fernox f1 express, but others are available

paragp

anyone out there who can shed some light on the inhibitor question please