Question for a plumber!

SnoopZ · 13-02-2009, 21:50

I'm having to drain my central heating system right now because a radiator valve is broken and leaking upstairs.

I've got a megaflow central heating system which means i just have a tank upstairs in the airing cupboard and mains cold water to all the cold taps.

I've turned the boiler off and the hot water, and central heating off at the timer.

I was also told to turn the mains cold water off under the kitchen sink which obviously means i have no water even from the immersion heater in the tank.

Question:

Do i NEED to keep the mains water turned off or will it fill up the heating system again with it on, even though the boilers off and all switches to timer are off?

Thanks for any help.

monkey2468 · 13-02-2009, 22:06

As far as I am aware, if you have a tank, it is a direct cold fill from the mains, but only for the water that needs to be heated, and is seperate from the heating system its self. Although i am NOT a plumber.

bhoywonder1967 · 13-02-2009, 22:10

Hi Snoopz,

I'm not a plumber but I believe as long as you isolate the tank and/or the boiler then you should be able to keep the mains cold water running at the tap.

Your tank should* have an isolation valve, or failing that an isolation valve should* be fitted where the water enters the boiler, if you can stop the water entering the tank or boiler then you should be ok for water from the tap.

*I said "should", because depending on when the system was fitted you may not have isolation valves on either the tank or boiler. This is only a relatively recent requirement i.e 10+ years in England & Wales or 5+ years in Scotland.

SnoopZ · 13-02-2009, 22:17

I've got a isolation valve at the bottom of my tank so you're right turning that off will let me have cold water, but what i wanted to do is use the hot water thats in the tank. Is that not possible?

---------- Post added at 22:17 ---------- Previous post was at 22:14 ----------

Quote:

Originally Posted by monkey2468

As far as I am aware, if you have a tank, it is a direct cold fill from the mains, but only for the water that needs to be heated, and is seperate from the heating system its self. Although i am NOT a plumber.

Yes that is what i thought but after i spoke to a pllumber over the phone not so sure anymore.... Maybe i'll risk it and see if the heating starts spewing water out again!

Matth · 13-02-2009, 22:17

Unusual system, looking up, it seems that the entire system is mains pressure (does that apply to the heating loop as well).

If so, any isolating valves will be mains pressure types, rather than low pressure gate valves.

NB. The isolating valves will invariably be jammed when you need them!

There may be a seperate valve for isolating the heating loop!

bhoywonder1967 · 13-02-2009, 22:21

Have you checked to see if the leaky rad has an isolation valve? If you can isolate the leaky rad from the system then you can run the rest without any issues.

Also, check to see if you can switch the boiler to hot water only mode, that way at least you'll have hot & cold water, but no heating till you've got the rad fixed.

SnoopZ · 13-02-2009, 22:23

I can't isolate any radiators unfortunately, and i just have an off switch on the boiler.

monkey2468 · 13-02-2009, 22:33

Just to clarify what I was thinking, the water in the tank is cold mains filled and be can heated via immersion seperate to the heating. If the boiler has been isolated from the cold mains fill and the normal mains feed to the taps can still be used the tank should still fill up when the hot immersion water is used.

JUST TO REITTERATE, I AM NOT A PLUMBER, put using my Vulcan logic and reasoning!!

bhoywonder1967 · 13-02-2009, 22:38

Only other thing to check is to see if the outflow pipes can be isolated, but it can be tricky to get the right one as they're not always labelled.

You should have 1 incoming cold water pipe and depending on the system setup 2-4 coming out to supply all the rads and hot water taps.

As I said, I'm not an expert at internal plumbing but know much more about external i.e. mains connections etc. I work for water board and some of the callouts for leakage end up being about situations like yours and we're not allowed to help if the problem occurs within the property.

idi banashapan · 13-02-2009, 22:45

call a plumber - 118 118

SnoopZ · 13-02-2009, 22:46

Thanks guys for the help, but as i'm not a plumber either i think the best course of action is to leave everything off over night. I have tried turning the mains water on and nothing is ****ing out the drain plug on the downstairs radiator yet! Not sure if that's a good sign or not. I'll leave the emersion on tonight and quickly turn the mains water on in the morning so i can wash etc. Hopefully a plumber will come soon! I spoke to 1 earlier but can't contact him to book him yet, so will try again in morning. Atleast the waters stopped leaking!

Mick Fisher · 14-02-2009, 15:17

Turn off both the radiator valves to the radiator with the leaky valve. Now drain the radiator. If it is not too big then remove it to give yourself more space to work.

Now get down to your local plumbing supply wholesaler or 'maybe' a DIY store and get a aerosol of Pipe Freezer. Follow the directions on the can and after successfully freezing the pipe to the leaky valve, remove and replace it. Having accomplished that, and made sure the valve you just replaced is CLOSED.

You can replace your radiator at your leisure.

Job done with no drain down.

Copper pipes only, I never came across a system with plastic pipes so dunno what would happen. I suspect the plastic might fracture.

SnoopZ · 14-02-2009, 15:26

I can't turn the valve off as it'll come off in my hand when i turn it and flood the room.... found that out Friday hehe.

System is drained now but this is the second vlave that's broken like this so might get a plumber in to replace all the others if needed rather than do it myself.

Thanks for your help.

idi banashapan · 14-02-2009, 15:40

I'm sure that was the advice I gave earlier in the thread!! what, no good rep!!!!???