Can't find Drain Cock location

[egtrev]

Hello,

I'm looking to move a radiator, or potentially two radiators to new positions.
The issue I'm having is I can not seem to find a drain off cock anywhere on either the flow or return, I've had most of the carpets and floorboards up checking the runs to see if I can find any but I can't, I also checked outside and in the boiler cupboard but nothing there either.
I have a bungalow with a combi boiler with 8 radiators all piped under the floorboards and then come up through the floorboards to the radiator valves, they all seem to be on roughly the same level.
See attached basic plan of how I think the piping work is from what I've seen (drawing may not be technically correct or exactly right but just for reference)

Can anyone advise on where they think drain cock may be located, or advise where there should be one so I can potentially fit one for making this easier in the future?

Thanks for any help.

 

[oldbuffer]

1. Are you sure none of the radiator valves have built in drain offs?
2. If you fit one it doesn't really matter where it goes but it should:
2a. Drain from the lowest point of the system, or the lowest practical point if pipes are all below floors.
2b. Have easy access to outdoors and a foul water drain.
2c. In theory be fitted to the return pipework as the water temperature is marginally lower. Personally I fit one to the flow and one to the return as it makes drain down quicker.
3. If there are no drain off points, see below.

To drain down where no drain cocks fitted.

1. Locate a radiator on the ground floor convenient for a run of garden hose to outside foul drain.
2. Turn off boiler.
3. If you have a Feed and Expansion (F&E) tank (small tank in loft):
3a. Shut off the water supply to the tank.
3b. Bail the water out of it and clean it. Otherwise any sludge will get washed into your heating system.
4. On selected radiator:
4a. Turn off both radiator valves. Count the number of 1/8 turns required to shut the lock shield, so that it can be returned t its original position to maintain system balance.
4b. Bleed any remaining pressure from the radiator via the bleed screw.
4c. Undo the nut securing one of the valves to the radiator. (NOT the valve securing the valve to the pipe). Drain the water out of the radiator into a baking tray or similar. Protect surrounding surfaces as the water may be black, and if so will stain anything in sight. Old towels also very useful.
4d. Slacken (but do not undo) the nut holding that radiator valve to the pipes, and swivel the valve through 90 degrees so that its open end faces away from the wall.
4e. Attach a hosepipe to the open end of the valve using insulating tape or similar. Wrap plenty round the hose and around the valve.
4f. Open the valve and let the water drain through the hosepipe to a foul drain outside.

 

[Hugh Jaleak]

Have you checked outside? Sometimes Drain Off's are fitted externally, even more handy if above a Gully so the system can be drained without making a mess.

 

[egtrev]

Thanks oldbuffer.
I've double checked the radiator valves just now and none of them have a drain off on them.
I'll follow your great guide and try and get it drained, I'm just surprised there isn't one, doesn't make sense to me not to have one.

Regarding fitting one, I was thinking of replacing some TRV's/valves as a couple are pretty grubby looking, would I be best getting a couple with drain off valves built in, I'm thinking that would be the easiest from a fitting point of view, maybe one on the radiator in the kitchen nearest the front door? (all foul drains are at the front)
Alternatively could probably get one outside but would be harder/more work.

Hugh Jaleak, I didn't see anything but I will have another look outside tomorrow again.

Appreciate the help/advice.

 

[Hugh Jaleak]

If you can't find a Drain Off point anywhere, then use a self cutting washing machine tap to break into the pipework to drain down. Once you've got the system emptied you can remove that, (and the holed section of pipework), and fit a (Type A are better) Drain Cock for future requirements.

 

[mcprinter]

DIYer. Also had no Drain Cock I could find.

Did exactly what Old Buffer described and then removed the Lockshield. Replaced it with one with a Drain Off.

Don't forget to add Inhibitor when refilling.
If your Water is black, might be worth running a Cleaner through it.
Old Buffer wrote an excellent step by step for that