Help! Draining hot water off?

[Gerry555]

Hi, I need to replace the gate valve and zone valve in the pic below and there's still (hot) water in the pipes shown, though I've drained all the radiators etc.

I've just opened all the hot water taps and they've run dry. Is that enough to get rid of all the hot water, or do I need to drain off the hot water tank too (or anything else for that matter)?

I just started the job this morning, so need advice quick - don't want water flooding the flat downstairs - so any help appreciated. Thanks.

 

[Gerry555]

Whoops, didn't spot the bleedin' obvious! There's a little drain off valve to the right.

Anything else I need to do??

 

[nickso]

you need to drain the heating not the cylinder.

the drain cock is for draining the heating but id be surprised if it still works judging by its condition. even if it does drain it may not seal up again.

 

[chr15]

If the drain off cock doesn't work then drain off at a radiator somewhere on ground floor-don't forget to isolate cold supply to feed and expansion cistern-and keep a couple of old towels spare.

 

[Gerry555]

Thanks, thankfully the drain off valve is still OK and didn't leak once sealed again.

I've replaced both valves. Initially I had a tiny bit of water running down the bottom pipe under the new gate valve, but I drained the system down again, pushed the pipe in a little higher and it seems OK now.

Question, is it OK for me to run the system for a short time without inhibitor in for the moment? Because of the initial leak, I filled the system up totally to see if I'd fixed it second time round. All's well, but the pipes are cool - the acid test will be when they expand a little once hot. I don't want to introduce inhibitor only to find I have leaks once things have warmed up, then flush it all down the drain, so is it OK? Just for an hour or so?

Secondly, when I finally do introduce inhibitor, should I pour it directly down the pipe of the header tank, or just chuck it in the tank then turn the water on again?

 

[Soggy_weetabix]

You got lucky my friend!

Next time, use a bung kit.

Dave

 

[JohnD]

put it in the F&E before you fill the syst, then it will get washed down into the pipes as the water flows. It helps to stir it around at first to make sure it is well-mixed and doesn't just collect at the bottom of the cistern.

If the system is already full, drain a couple of buckets of water out with the ball-valve tied up before you add the inhibitor, so that when you add it, it will be drawn down, and washed down by the water that follows when you untie the ball.

 

[Gerry555]

put it in the F&E before you fill the syst, then it will get washed down into the pipes as the water flows. It helps to stir it around at first to make sure it is well-mixed and doesn't just collect at the bottom of the cistern.

If the system is already full, drain a couple of buckets of water out with the ball-valve tied up before you add the inhibitor, so that when you add it, it will be drawn down, and washed down by the water that follows when you untie the ball.

OK thanks John, I'll be draining the system to at least half full before I apply it.

So, is it OK to run the system for an hour or so without inhibitor (so that I can check for leaks when the pipes are hot)?

 

[chr15]

put it in the F&E before you fill the syst, then it will get washed down into the pipes as the water flows. It helps to stir it around at first to make sure it is well-mixed and doesn't just collect at the bottom of the cistern.

If the system is already full, drain a couple of buckets of water out with the ball-valve tied up before you add the inhibitor, so that when you add it, it will be drawn down, and washed down by the water that follows when you untie the ball.

OK thanks John, I'll be draining the system to at least half full before I apply it.

So, is it OK to run the system for an hour or so without inhibitor (so that I can check for leaks when the pipes are hot)?

Yup-go for it

 

[Gerry555]

Excellent, thanks for your help everyone. Great forum!!