Flow and return..?

[dizz]

Chris - If you read Agile's post that will solve 50% of your problem.

If you have a filling loop by your boiler,

http://www.screwfix.com/prods/46605/Plumbing/Boilers-and-Accs/Combi-Straight-Filling-Loop

and drain cock on one of the radiators, or near the boiler

http://www.screwfix.com/prods/99939/Plumbing/Brassware/Drain-Cock-Type-Heavy-Pattern-15mm

you'd be far better off, trying to drain the water from the drain cock, using a hose

http://www.screwfix.com/prods/73386...es-Fittings/Hoses/Hoselock-Maxi-Plus-Hose-30m

into a bucket

http://www.screwfix.com/prods/17252...ics/Builders-Bucket-Yellow-3-Gallon-Pack-of-3

by bleeding all the the radiators

http://www.screwfix.com/prods/49255...e-Panel-Double-Convector-Radiator-300-x-600mm

with a bleed key

http://www.screwfix.com/prods/16909/Hand-Tools/Plumbing-Tools/Radiator-Tools/Radiator-Valve-Key

at the top of the radiator.

This will drain the water from the radiators into the bucket (you may have to empty the bucket

http://www.omick.net/water_reuse/emptying gw bucket.jpg

a number of times.

But at least you can make a cup of tea, watch the football, as you change the TRV without having to wonder whether the freeze will unfreeze.

When you'r done, close off the drain cock, use the filling loop to refill the system, but remember to put inhibitor into the system, bleeding the radiators as you go.

http://www.toolstation.com/shop/Hea...ves/System+Inhibitor+1+Ltr/d230/sd3235/p94504

by putting into the 15mm pipe where you put your TRV or filling into the top of the radiators using a funnel

http://www.screwfix.com/prods/49184/Van-Car-Accessories/Automotive-Accessories/Autocare-Funnel-Kit

That's what I'd do anyway.

But if you want to freeze the pipe ....

 

[PEDANTICVINDICTIVEMAN]

Wifes always freezing, and been a long time since emptying any load, having a soft towel is always handy if any loads empty.

 

[ChrisNaude]

TYVM MrGas. That answers another question I had. " How do I know if the ice-plugs have set?"

 

[mrgas]

clean the pipes so you get good contact between the freezer heads and the pipe
Turn on freezer and wait until frozen... the time for this varies but you can tell when they are frozen by placing a wet finger on the other side of the pipe from the freezer head and if your finger sticks then it is most likely frozen.
To proove its frozen you have tha rad valves open and then open the vent plug on the radiator and see if you get water coming out. You will get some as the radiator is still under pressure even with the pipes frozen, but it should quickly stop.
Leave the vent plug open for a few minutes and if no water comes out then the ice plugs are good.
Worth remembering that heating water is often filthy black stuff that stains carpets!
Good luck.

 

[dreadnoughtheating]

Dread Naught by name, Dread Naught by nature...... (now which classic film inspired to pick that username?)

I always thought it was about Margaret Rutherford.

Mr. W.

Try Terry Thomas, owner and proprietor of Dreadnought Motor Traction Co, of Wantage (Blue Murder at St. Trinians). Absolute rotter.

DH

 

[doitall]

I would turn the rad off on the valves after deciding which is the flow, then drain and disconnect the rad.

Make the new tail in whilst the freezer is doing the business, then check the pipe is frozen by opening the valve.

All you have left is undo one nut and doitup again with the new valve, assuming you buy a compatible valve with the existing.