Draining central heating

[Mgrant]

What is the best way of draining a heating system to repair a pipe with a nail in it the pipe is downstairs. Want to replace with two soldered slip sockets and a bit of pipe. So will need all the water out. Do I need to open all radiator bleed vales on the upstairs radiators?

 

[kozak1968]

With a pressurised system open all the air vents, if its open vent then turn the cold feed to the expansion tank off. Turn the electrics off first you dont want the boiler firing up.

 

[Jay The Plumber]

as above.. start draining and open rads from the highest rad downwards.

 

[mejmag]

Make sure system is completely drained, as any dripping water from the cut pipes will make soldering very difficult.

 

[Mgrant]

Thanks the pipe is in the wall on a drop to a downstairs rad. That has on drain valve on it guess I'll be best draining through the valve on this rad. Not the only drain cock which is on a different drop.

 

[Mgrant]

 

[Mgrant]

That's the said heating pipe that needs repairing. Bit torn between cutting the pipe above or below the socket

 

[PlumbBobBob]

cut the pipe where the nail has gone through then you will only need one slip coupling.

 

[Masood]

cut the pipe where the nail has gone through then you will only need one slip coupling.

Meh. Bit of denso will sort that out...

 

[Rickster123]

Meh. Bit of denso will sort that out...

Or just hammer a bigger nail in the hole..

 

[SimonG]

Nah. Just clean it up, bit of flux and a bit of solder on it. Champion.

 

[mejmag]

Don't forget to add inhibitor when complete.

 

[Mgrant]

cut the pipe where the nail has gone through then you will only need one slip coupling.

Thanks then just have to make sure I don't disturb the socket below. Which as you can see on the pic you can't even see a solderd ring around it. Do you oftern see this on yorkshire fittings? I usually use end feed

 

[lame plumber]

freeze either side, simple and saves time

 

[Mgrant]

Not enough room to get a spray kit on bottom side and sure you can't solder near them. I dont have a electric freeze kit

 

[Mgrant]

Don't forget to add inhibitor when complete.

Any preference with which inhibitor to use? Not sure if anys in at momment but I don't think mixing of inhibitors is a problem?

 

[Dotty]

What boiler do you have?

 

[GrahamM]

Thanks then just have to make sure I don't disturb the socket below. Which as you can see on the pic you can't even see a solderd ring around it. Do you oftern see this on yorkshire fittings? I usually use end feed

That is a solder ring fitting. They are pre-soldered. The little raised hump just along from ends contains just enough solder to bond after you put heat on it. Might not see any solder exiting the end of fitting unless has had heat on to long.

 

[Mgrant]

Valliant eco tec pro

 

[Ch4 plumbing]

pop the hose on, drain system opening all rad vents on the upper floors, clean the pipe and cut on the hole, use a slip sock either bought or made by you, solder refill and test then drain a bit and add inhibitor.

dont worry about the existing sock unless you plan on heating the pipe up for a long time.

 

[Mgrant]

Thanks there's a drain valve on the system but not one on the pipe drop that feeds the radiator that the damaged pipe is on. So would I be best draining through the rad valve on this drop instead. By disconnecting the valve from the rad and connecting a hose. If there's enough play on the pipe.

 

[PlumbBobBob]

yes that will do, just turn the valve on the pipe to make it easier to drain down

 

[Ch4 plumbing]

if its a 3/4" union on the rad valve use a tap hose connector and join it straight onto your hose, no leaks no fuss!

 

[mejmag]

Use Sentinel X100 inhibitor. But really I find no difference between this and Fernox.

 

[mejmag]

And yes, as Ch4 plumbing says, fill the system back up to test for leaks before adding inhibitor, otherwise you'll be draining down again and buying another litre!!