Do I need to drain the system

[Jim]

Hi all

I've got what I believe is a completely sealed HW/CH system. ie no cold water tank, no expansion tank, mains pressure hot and cold water.

In the kitchen there is some piepwork on the CH side of things that was plumbed to a heater mounted in the plinths. We never use the heater so I want to remove all traces but I don't ant to drain the CH (as I haven't got the equipment to add the system protector via a rad valve) However if the system is sealed could I just cut the pipework off and let gravity/vaccuum do their thing ie only a small amount of water would be lost before the vacauum stopped any more coming out? Also if this was to work how likely is a solder end stop going to be possible (given the presence of water) or will I have to use a compression fitting

Thanks

Jim

[TMC]

Tony

[sm_jamieson]

You won't solder with water in the pipe. It draws the heat away. Also I tried on a pipe that was only slightly dripping water, but the flux got washed away. You can get a compression fitting on fairly quickly, but you will lose some water. Simon.

[TMC]

You could use a pipe freeze kit and copper pushfit end stops

Tony

[John Rumm]

Note that Wickes do inhibitor in an aerosol can plus short length of tube that terminates in the same fitting as used on most filling loops. Total cost about £20 for the pair. Hence adding inhibitor is just a case of screwing the pipe onto the filling loop point an attaching the can.

You will obviously lose any positive pressure in the system, and after that you may be lucky and keep the remainder in there.

Are there not taps on the connection the heater you could simply turn off and abandon?

No chance whatsoever...

(on potable mains water you can sometimes solder a pipe with a very slow drip by stuffing some fresh bread rolled up into a small ball up the pipe - it flushes out a tap once the water is back on)

That or pushfit. If you use compression, assemble the fitting first, so its ready to slide onto the pipe!

[NOSPAMnet]

I don't understand why boiler fitters don't add a filling point when doing that work .I insisted on it when mine was fitted .

[Roger Mills]

You'll need to de-pressurise the primary circuit, and re-pressurise it when you've done your pipework mods.

Is the plinth heater still in situ, complete with radiator valves? If so, close both valves, crack open one of the valve to rad unions and drain the radiator. You can then undo both unions and remove the radiator. Assuming that the filling loop isn't permanemtly connected and turned on(!), you can de-pressurise the system by opening one of the plinth heater's 2 valves, and collecting the water in a bucket. You probably won't get more than a couple of litres coming out. Do the same with the other valve - you might get a drop more water. Once you reach the state where both valves are open but no water is coming out, you can tidy up the pipework by cutting the pipes off at a convenient place.

As others have said, don't try to use solder end-stops - there may still be

*some* water lurking in the pipes. Compression fittings are the safest. You *can* use pushfits - but only if you've managed to cut the pipes cleanly and removed any burrs and any traces of paint - otherwise you'll damage the rubber seals, and they'll leak.

Finally, use the filling loop to re-pressurise the system. If only a couple of litres have come out, the dilution effect on the inhibitor can be ignored. If a lot more has come out, you'll have to find a way of injecting some more inhibitor.

[Ed Sirett]

There almost certainly will be a filling point ( either in the boiler itself or externally fitted).

I'm amazed that you have seen so many system without a filling point. Now systems without a drain point, quite a few, and without a functioning drain point many more.

[NOSPAMnet]

I wasn't speaking from experience but from reading messages in here which suggested that their systems didnt have one ...like the OP in this case who seems to be saying he'd need to fill it via a rad

[Ed Sirett]

The matter is discussed in the FAQ. There is a difference between having somewhere to put in water and put in inhibitor. (There was only one thread IIRC about no filling loop and that was becasue the installers hadn't shown the user the /internal/ filling loop).

Inhibitor may have to be injected into a radiator if /all/ the radiators are of a certain (roll top) design.