Can I change my RV's to TRV's using freezer spray?

[lastminute]

..as above, instead of draining the system.!

 

[n0legs]

I know some who've had really good results with freezer spray and others who've had absolute disasters.
My concern would be trying to freeze the contents of the radiators. There isn't any other isolation point between rad and valve, you would be changing the tail in the rad as well IIRC.

 

[Doug B]

If you're changing more than a couple of valves you may as well drain the system, you are going to have to drain the radiators you are changing the valves on anyway even if you freeze the pipe.

 

[blackrodd]

FWIW, Before a plumber comes along, If you have very many flow and return pipes each radiator side to freeze, it will cost a few bob in cans and the water in the system would need to be cold-ish to work too.
You have draining or filling issues I suppose?
Regards Rodders

 

[Graham Orm]

Freezing kits work, but as stated they are not cheap. It's much easier to drain the system if you have more than one rad to do. The short answer is yes it will work.
Make sure the system is stone cold before you start and the rad valve where you are working is closed so that no water can pass either way whilst you're freezing as that will stop it from freezing.
Likewise, if the ice plug melts and water starts trickling past it before your're ready you won't be able to re-freeze it again unless you can stop the flow.
Make sure the ties at the ends of the cuff are tight.
Keep two hammers handy or a pair of mole grips and be prepared to flatten the pipe if it all turns plumbs up!

Where I served my time they had big gas bottles like small welding bottles with a freezer cuff attached. We used them on inch lead, and they never failed!

I carry an over the shelf freezer kit on my van but dread the day that I need it. I've had success with them in the past but still have little confidence in them.

 

[porker]

I had a system in the past which I avoided draining down at all costs because getting an air lock out afterwards was so difficult. It was a gravity system so I used to use bungs in the header tank and overflow and that would hold most of the water by creating a vacuum in the system. For the radiator I used to tighten the lockshield on the opposite end to the TRV and then using a wet vac crack the joint on the valve. I could suck every drop out of the radiator without getting any on the floor (but would still pack underneath with rags just in case). If you do try freezer spray make sure the system is cold by turning off the CH well in advance. Sometimes the pipes feel cool but the water is not. Then use a whole can on a 15mm pipe. I've had mixed results so if the flooring is not water resistant (i.e. carpet) I would be very wary.

If draining down and refilling is not a problem though, this will always be the safest option.

 

[Jim22]

I have not used them but have seen them used to great success, although not for "routine" work like rad valves. That doesn't help answer your question, but I was given some great advise that may be relevent. Take a pair of mole grips and lightly "crimp" the pipe behind the ice plug -that stops it shooting out if it does start to melt (as it melts outside in), and when they go, they go - apparently.

 

[Graham Orm]

I had a system in the past which I avoided draining down at all costs because getting an air lock out afterwards was so difficult. It was a gravity system so I used to use bungs in the header tank and overflow and that would hold most of the water by creating a vacuum in the system. For the radiator I used to tighten the lockshield on the opposite end to the TRV and then using a wet vac crack the joint on the valve. I could suck every drop out of the radiator without getting any on the floor (but would still pack underneath with rags just in case). If you do try freezer spray make sure the system is cold by turning off the CH well in advance. Sometimes the pipes feel cool but the water is not. Then use a whole can on a 15mm pipe. I've had mixed results so if the flooring is not water resistant (i.e. carpet) I would be very wary.

If draining down and refilling is not a problem though, this will always be the safest option.

That wetvac is a great idea, for draining a rad I usually use a pair of shallow cat litter trays with a bucket or bowl along side and as you say, a big wedge of dust sheets underneath.

 

[porker]

A plumber showed me this and it works great. With the tray I always got some water dribbling down the pipe etc. and black water on off-white carpet did not make me popular!

 

[Doug B]

The freezing kits work well I've never had a problem with them, the last one I did recently was on a lead rising main in a row of old terraced houses where none of the residents knew where the external stop tap was.

The trick I've found is when you think it's frozen squirt some spray on the downstream section of the pipe below the muff, if the spray frosts up & remains there the pipe is frozen, if it disappears then it isn't.

 

[Ghengis]

Combi boiler or low pressure system (hot water tank)?

 

[Eric The Viking]

I've had both success and failure with freezer kits. Like Graham, I've had one for about ten years knocking about, but I'd do pretty much everything I can to avoid having to use one.

if the radiator pipes are painted, that will hinder the freezer spray. You may get an ice plug, but not as strong as you think. You can only check for freezing outside the pipe (obviously) so a good amount of frost formation at the ends of the cuff isn't a reliable indicator if the pipe has been painted.

Avoid unless totally desperate.