Unable to undo radiator nut

[HumanAstronomer3194]

There is a radiator in my parents house that is falling off the wall that I want to fix before it falls off. I've already replaced another radiator in their house last year but this one is proving to be a bit more difficult.

I'm trying to undo the nut by moving the adjustable wrench on the left from the floor towards the wall and I'm using the footprint wrench to try and prevent the valve from moving but no joy. I also tried moving the other direction just to make sure I wasn't moving it in the wrong direction but that didn't work either.

I had read on here to try heating up the nut with the blow torch (which in retrospective is dangerous seeing that the tail is pex)

But that isn't work either (though I forgot to try both directions even if everything I've read online says the nut moves in a clockwise direction when looking at the end of the radiator).

What I am thinking of doing next is to try and do a live fix by with using bungs (eg https://www.amazon.co.uk/dp/B01JPC12O6/) but by blocking these two pipes circled in red

There is a back boiler in the house too so there is an extra overflow pipe which I plan on blocking too.

So my question is have I done anything wrong in what I've already done and is my plan to replace the valves in a live fix (but creating a lock with the bungs) sound like it would work or am I planning on doing something crazy?

Also what sort of nut is that on the TRV?

As the lock shield side is what I would be expecting

And for reference this is is why I'm trying to remove the radiator

 

[CBW]

You could try bunging, but try using the footprint and adjustable the other way, IE, the adjustable to stop it moving

 

[Dereekoo]

You are screwing the right way just more force required, it would help if you had an assistant holding the wrench so you could use your full force on the adjustable, I had same issue trying to take off to of a top once, brute force and assistance won the day.

 

[opps]

You want the adjustable spanner to go upwards.

Be advised that with the TRV crown removed, it is fully open. I would move the wrench to the side of the TRV body and apply opposite pressure to that of the spanner.

I am not a plumber though. One might have a handy hint.

I have no idea why the nut on the underside of the TRV doesn't look like anything that you or I have encountered.

 

[Exedon]

I have no idea why the nut on the underside of the TRV doesn't look like anything that you or I have encountered.

It's a internal fitting 1/2 in female thread used to be some old danfoss trv's like that.
As for undoing it try taping nut with a hammer first.
Then hold body with grips and give it some welly.
Unless system is drained or you like getting wet fit decorating cap on trv.

 

[HumanAstronomer3194]

Thanks all for the advise. I'll be back at the weekend and try everything suggested here. I forgot to mention I had already tried hitting the valve with the valve with a hammer but with no luck.

I had removed the TRV head just to get a better grip with the footprint wrench. I don't have a decorating cap but maybe the replacement TRV I have will have one or that or just put on the back the old TRV head.