Bung a Combined Feed and Expansion Tank.

[ashleyw1]

Hi,
I need to fit a single trv. Don't want to drain my system again so will use a bung.
It's an open vented system with a combined feed and expansion tank. Will I just need to use 1 bung or am I missing something obvious.
Thanks.

 

[TonyW2]

Two.
Expansion pipe and inlet pipe to system from c/h feed tank.

Edit---see later---- as expansion is back up via feed.

 

[dreadnoughtheating]

Are you feelin' lucky Punk?, well, are ya?

Assuming you have an open vent system (hope its not a boilermate)

This is not a task for the faint of heart. You need two bungs, one for the cold feed (not all gate valves hold anything like 100%) and one for the open vent. Be prepared to have a couple of litres to glug through, nerves of steel remember, and turn off the other end of the rad( the rad will still be full and want to also empty itself over your carpets)

Or, you can beg/steal/borrow a freezer kit for the pipe leading to the TRV (turn the other rad valve off first and drain the rad into shallow trays - careful now, that horrid black sludge goes everywhere...... don't ask.....)

Or, snatch it, with a pre-pasted new valve (hope you don't have 'Prestex' thread nuts.... Dont' ask....)

Or, drain and refill the whole system, and add some inhibitor while you are at it.

Or, get a pro in.

DH

 

[ashleyw1]

Thanks,
Think I'll drain down again. Time it takes to get rid of the airlocks was putting me off.

 

[dcawkwell]

Why?

It's so easy just to drain it down.

Open drain valve and go away have nice cup of tea.

Replace radiator valve taking your time.

Close drain valve. Open her up. Job done.

 

[ashleyw1]

Thought plugs might be an easy option.
Because of the combined feed expansion tank I only thought 1 bung was needed as I have no expansion pipe going into the tank.

 

[namsag]

Combined cold feed and expansion?
So you have only one tank that supplies cylinder and heating ?
That will mean you prob have a primatic cylinder and under no circumstance do you bung these as the cylinder will implode.

Or do mean combined cold feed/expansion PIPE .
with 2 tanks one feeding cylinder and one feeding the heating.
Bung it these hold 99% of time and very quickly .


Brave
Turn off opposite side of rad , dust sheets and snatch the valve give yourself a bit of excitment for the day

 

[ashleyw1]

It's the cold feed expansion pipe which is combined. 2 tanks. Small one has 1 pipe. Big one has feed and expansion.

 

[TonyW2]

Please confirm that the small tank has a pipe that feeds the central heating system.
How does the expansion pipe from the central heating discharge?

But by now you could have drained the system and replaced the valve!

 

[ashleyw1]

Small tank has a feed to the central heating. Same pipe is the expansion as well. (underwater.)

 

[namsag]

Bung the small one peice of cake, buy the soft bungs as opposed to the hard ribbed ones

 

[ashleyw1]

Thanks, will give it a go.