drain valves not opening

[satch]

Hi,

I’m trying to drain a central heating system but the drain valves appear to be stuck i.e. no water flows out of an attached hose (the hose is ok). There are four in the system on various lower floor radiators but all seem blocked. They turn okay as if they are opening, so the problem must be the washer or inner part. I unscrewed one slightly too much and black water went everywhere so I don’t want to happen again on the others. I’ve tried tapping them but still no good. Does anyone have any ideas?

 

[breezer]

if black water came out and as you said went everywhere, they cant be blocked, i would guess your hose is kinked or you are running it too high up

 

[corgiman]

ping the washer out and whack the hose on it PDQ!!

lots of tissue would be the order of the day

Sorry

 

[satch]

Hi Breezer,

Water came out because I unscrewed it too much and the whole inner fitting fell out leaving a hole. On inspection it appears the washer had compacted and although brittle must have stuck at the lower end forming a seal I’ll try pinging the washer as CORGIMAN suggests. Cheers.

 

[The Baker]

Some drain cocks on rads just do the rad if both rad valves are closed.

Some just let every thing out.

Get your self a Wet and dry Vacuum cleaner, have an assistant ready with the hose to distract the black stuff whilst you pick at the washer.

Do it with the rad valves closed and if your lucky your wet/dry vac will only have to cope with the contents of the rad.

Once you have fixed one drain cock drain the system from there.

The other duff cocks can be sorted after and hopefully with just a rad full at most to cope with.

But, a word of advice, if its an open vented system, get your self up into the attic and empty the feed and expansion tank of its water and anything else that may be in it, you wont want to drag debrie down into the system.

Tim

PS am assuming you have bought some new drain cock washers

 

[JohnD]

if you unscrew the plug so much it falls out, you may be able to put your thumb over the hole the plug came out of, and the water may then run down your hose

once you have drained the water, you can take out all the plugs, and put new washers on them. You will have to poke out the old bits of washer from the DOC. The DOC washer is not the same size as a tap washer and I have not seen them in DIY sheds but a plumbers merchant will have them. Until you fit new washers the old DOCs will not seal reliably.

If the DOCs are compression fitting it may be easy to take them off and fit new ones. However if it is fitted with old jointing compound that has gone hard it can be difficult.

If you can find new DOCs of the same type as your old ones, you may be able to just fit the new plugs (but different types may not fit each other)

I am just a householder but recently went through something similar.

edited: on re-reading I think you have something like this?

 

[satch]

Thanks for the advice everyone. Im going to get some new valves before doing anything else so I'll be doing it next week/weekend. I'll let you know how I get on.
Cheers

 

[gremlin16]

if you unscrew the plug so much it falls out, you may be able to put your thumb over the hole the plug came out of, and the water may then run down your hose

don't put your finger over hole, do what we do and get someone else to plug hole with finger, such as an apprentice or even the wife.

 

[numpty1]

shut both rad valves,empty rad, fingers over ends,lift rad off,drain through valves,replace/rebuild doc/valves,refit rad,refill and add inhibitor.

 

[ChrisR]

Good grief it's easier than all that.
Get some green garden hose, and a red thin screwdriver. One that's bent at the end is good, but straight will do, or an old coat hanger at a pinch. Spike the hose with the screwdriver, it'll hardly leak a drop:

View media item 1590

 

[gremlin16]

I like that Chris

 

[numpty1]

very good

 

[corgiman]

Good grief it's easier than all that.
Get some green garden hose, and a red thin screwdriver. One that's bent at the end is good, but straight will do, or an old coat hanger at a pinch. Spike the hose with the screwdriver, it'll hardly leak a drop:

View media item 1590

Thats a top idea Chris



cheers mate

 

[Class of '55]

top man! i've been in this game since before i could shave and they now call me Papa Smurf which just goes to show you'll never know it all. Lets face it it's what makes our jobs a bit more interesting.

 

[satch]

Hi All,

Just thought Id let you know I did as ChrisR suggested and it worked a treat. Ive now drained the system and fitted new drain valves. I’m currently letting it run for a bit with Fernox F3 in the system, Ill drain it and flush again soon then add F1 protector. I think I may change the bathroom towel warmer to a proper rad whilst I’m doing it.

Cheers again for the advice.