Replacing jammed TRV without draining system

Paul007

Hi,

I have an upstairs bathroom trv that has jammed shut and no amount of tapping or coaxing with a pliers will open it up.

I have a replacement valve and am hoping to avoid the hassle of draining down and buying inhibitor or using pipe freezing kits.

Would I be right in thinking, if I close all other valves on the the upstairs rads and shut off the system water supply, I could replace the trv only losing a pint or so of water in the process?

Btw, I have a sealed system.

youtheman

Paul007 wrote: »

Hi,

Would I be right in thinking, if I close all other valves on the the upstairs rads and shut off the system water supply, I could replace the trv only losing a pint or so of water in the process?

You'd be very WRONG (and very sorry later).

Dtp1979

Paul007 wrote: »

Hi,

I have an upstairs bathroom trv that has jammed shut and no amount of tapping or coaxing with a pliers will open it up.

I have a replacement valve and am hoping to avoid the hassle of draining down and buying inhibitor or using pipe freezing kits.

Would I be right in thinking, if I close all other valves on the the upstairs rads and shut off the system water supply, I could replace the trv only losing a pint or so of water in the process?

Btw, I have a sealed system.

Yes it's possible. Close the opposite side of the rad, make sure the filling valve is off, bleed the rad until water stops coming. Make sure you close the air vent.
Get a small amount of uni white or similar and rub it onto the chamfered edges of the new valve. Have a towel on the ground and all tools ready.
Be quick and you should lose very little water.

I wouldn't jump the valve but that's because I've seen it go wrong.

Wearb

As DTP says, it is possible, but for experienced people, I think. Things can go wrong, such as leaking valves on the other rads, different sized valves. Do it the way that you said, but make sure that all the water has stopped running before you break that joint at the radiator completely. Just loosen at it first. That way if the trickle doesn't stop, you will know that you will have to drain down the upstairs.

Cerco

Dtp1979 wrote: »

Get a small amount of uni white or similar and rub it onto the chamfered edges of the new valve.

Do plumbers still use flax on connections etc. or is that old school now ?

Dtp1979

Cerco wrote: »

Do plumbers still use flax on connections etc. or is that old school now ?

Not at all. I use flax on all male threads except for gas and oil.

jimbev

I was always led to believe that you left one rad without a tvr and that most rads in a bathroom will stick at some point because of the steam

Dtp1979

jimbev wrote: »

I was always led to believe that you left one rad without a tvr and that most rads in a bathroom will stick at some point because of the steam

Stick in a bathroom? Never heard or seen anything like that tbh

Wearb

Dtp1979 wrote: »

Stick in a bathroom? Never heard or seen anything like that tbh

Me neither.

Dont use trv's where there are room stats. Also if there isn't a bypass, have one rad without a trv, so that water will always have some circuit if everything else is closed.

jimbev

jimbev wrote: »

I was always led to believe that you left one rad without a tvr and that most rads in a bathroom will stick at some point because of the steam

Bathroom rads were traditionally chosen as a bypass rad as the bathroom is usually the only place you'd be naked and wet so the extra heat would be appreciated.

TRVs sticking is more about internal issues rather than external.

Wearb

gary71 wrote: »

Bathroom rads were traditionally chosen as a bypass rad as the bathroom is usually the only place you'd be naked and wet so the extra heat would be appreciated.

TRVs sticking is more about internal issues rather than external.

So much so that nearly all PRV's have a built-in programme to open and close them at regular intervals to prevent this calcification which causes sticking.

Dtp1979

Wearb wrote: »

So much so that nearly all PRV's have a built-in programme to open and close them at regular intervals to prevent this calcification which causes sticking.

What ya mean?

Wearb

I have Programmable Radiator Valves. They can be programmed for temperature and time. When they are off in the summer, the programme automatically opens and closes them to prevent the stem sticking. It is called an "anti calcification" feature.

Dtp1979

Wearb wrote: »

I have Programmable Radiator Valves. They can be programmed for temperature and time. When they are off in the summer, the programme automatically opens and closes them to prevent the stem sticking. It is called an "anti calcification" feature.

Ah! I saw prv and thought safety valve. Was wondering alright!