Adding radiator 'live' none pressurised system.

[camerart]

Hi,
I have a none pressurised central heating system and want to add another radiator at ground floor with floor boards.
This system is a pain to drain/refill, as it doesn't have an up and a down pipe from the tank, so I have to use a vacuum pump.

Anyway, I hope to cut one side of the radiator feed and quickly push a bung on a rod into it, Then feed an open stop valve over the rod and fit it on the pipe end, then pull the bung though the valve and quickly turn it off. Does this seen feasible?

Cheers, Camerart.

 

[terryplumb]

What do you mean by " it doesn't have an up and down pipe from the tank" ?
And why can't you drain the system and re fill ?

 

[camerart]

What do you mean by " it doesn't have an up and down pipe from the tank" ?
And why can't you drain the system and re fill ?

Hi T,
When I refill the system, all of the air doesn't come out, because the water entering the system from the tank uses the same pipe as the air coming out. I pull it out with a car oil extractor pump, while switching the pump on/off. The 80s plumber wants a talking to!
C

 

[terryplumb]

When you refill the system do you leave an air bleed valve on a radiator open upstairs to vent ?

 

[Madrab]

You have a combined feed and vent? You could back fill the system, attach a hose to the system at the drain point and then use mains pressure to fill the system that way.

If it's a gravity system though then you can bung the Feed and Expansion cistern. That'll create a partial vacuum in the system and will allow the pipework to be cut with a min of water escape. If you are cutting into the feed/return though, when cut it you will have 2 open ends to deal with. If they are 22mm pipes then have 2 push fit stop ends ready, cut and fit the ends that'll allow things to be managed.

 

[camerart]

When you refill the system do you leave an air bleed valve on a radiator open upstairs to vent ?

The only airbleeds are on the raiators, which I can't leave on, but go round bleeding all of them.

 

[camerart]

You have a combined feed and vent? You could back fill the system, attach a hose to the system at the drain point and then use mains pressure to fill the system that way.

If it's a gravity system though then you can bung the Feed and Expansion cistern. That'll create a partial vacuum in the system and will allow the pipework to be cut with a min of water escape. If you are cutting into the feed/return though, when cut it you will have 2 open ends to deal with. If they are 22mm pipes then have 2 push fit stop ends ready, cut and fit the ends that'll allow things to be managed.

Hi M,
The system is full and hot, and I don't want to drain it.
Previously I have used the way you suggest to fill the system, but never managed to get the air out without hours of fun.

I want to cut into the system, without getting any air into it, for the above reason, so I want the gravity pressure to keep the air out.

The route is through the radiator, so I will turn off the other side using the rad valves, so only feed not return
C

 

[ChrisJP]

As long as the system is not hot (that is, turn off the boiler before you start work) you can use a pipe freezing kit to form an ice plug and stop water flowing out of the pipe when you cut into it.

 

[camerart]

As long as the system is not hot (that is, turn off the boiler before you start work) you can use a pipe freezing kit to form an ice plug and stop water flowing out of the pipe when you cut into it.

Hi C,
If this freezing method involves a coil around the pipe and a none 'green' gas being purged into the atmosphere, then I not keen.

I'd like to know if my idea sounds possible, and if anyone else has used it.
C

 

[Mottie]

If this freezing method involves a coil around the pipe and a none 'green' gas being purged into the atmosphere, then I not keen.

I take it it’s not one of those nasty fossil fuel burning heating systems then?

 

[Burnerman]

Admittedly mine are below the floor, but I fit these to my system (gravity):

https://www.screwfix.com/p/flomasta-full-bore-isolating-valve-15mm/46860?gclsrc=aw.ds&gad_source=1&gclid=EAIaIQobChMIz4XKruWXigMV45ZQBh2D4QDQEAQYASABEgIeGvD_BwE&gclsrc=aw.ds

I quickly cut through the pipe with a slice, bung a thumb over the end then slide this thing into place.
I bet I lose less than half a litre of water every time.
John

 

[camerart]

I take it it’s not one of those nasty fossil fuel burning heating systems then?

Hi M,
No, it is one of those nasty fossil fuel burning heating systems.
C

 

[camerart]

Admittedly mine are below the floor, but I fit these to my system (gravity):

https://www.screwfix.com/p/flomasta-full-bore-isolating-valve-15mm/46860?gclsrc=aw.ds&gad_source=1&gclid=EAIaIQobChMIz4XKruWXigMV45ZQBh2D4QDQEAQYASABEgIeGvD_BwE&gclsrc=aw.ds

I quickly cut through the pipe with a slice, bung a thumb over the end then slide this thing into place.
I bet I lose less than half a litre of water every time.
John

Hi J,
Mine are also below floor too, so off to Screwfix.
Great thanks.
C

 

[Mottie]

Admittedly mine are below the floor, but I fit these to my system (gravity):

https://www.screwfix.com/p/flomasta-full-bore-isolating-valve-15mm/46860?gclsrc=aw.ds&gad_source=1&gclid=EAIaIQobChMIz4XKruWXigMV45ZQBh2D4QDQEAQYASABEgIeGvD_BwE&gclsrc=aw.ds

I quickly cut through the pipe with a slice, bung a thumb over the end then slide this thing into place.
I bet I lose less than half a litre of water every time.
John

Just a thought. If a 22mm isolating valve was fitted to the system feed pipe from the feed and expansion tank, could that be closed off effectively making the system a temporary sealed system (and therefore creating a vacuum) for future jobs of this nature, especially in this case where draining down and refilling is a major nightmare?

 

[Mottie]

Hi M,
No, it is one of those nasty fossil fuel burning heating systems.
C

Do you mean yes it is or no it is not?

If it is, a little bit of extra non-green gas into the atmosphere from a freeze kit won’t make much of a difference to your carbon footprint, would it?