Adding TRVs

Drox

TK Veteran
Hi,

I want to add some TRVs to my radiators. I will need to add them on to 6 radiators, which leaves 1 with a normal valve.

Has anyone ever used one of these pipe freezing kits? All my radiator pipes are plastic, around 8mm (I think). I'm wondering whether there area any risks from using these pipe freezing kits like the pipe bursting etc.

Currently have a boiler, hot water tank, and a cold water tank in the loft.

Thanks
 
Yep, deffo better to drain it down, and add inhibitor while you are at it.
And remember that some TRVs are directional, they will work in both direction, but are more efficient if installed in the correct direction, or just get bi-directional ones.
 
Also If it was one of the kits with spray can it would cost you a bit you would probably need a few cans, you can hire electric freezing machine but also not cheap.
If you are draining full system anyway why not replace lockshield valves while you are at it. Not much dearer for a pair of valves than it costs for single TRV. I know lockshield valves will still be working but even for appearancies sake it may look better rather than old valve and new :smiley:
 
Yep, deffo better to drain it down, and add inhibitor while you are at it.
And remember that some TRVs are directional, they will work in both direction, but are more efficient if installed in the correct direction, or just get bi-directional ones.

If I add inhibitor via the radiator, am I right in saying that I only need to do it one radiator and it will flow through the system?

Thanks
 
If I add inhibitor via the radiator, am I right in saying that I only need to do it one radiator and it will flow through the system?

Thanks
Yes, there's a fitting you can get that screws onto the bottle and into the radiator valve with a short hose between for easy filling
 
Fernox is good stuff,
But, if you have the system drained down, just pour it into one of the pipes before you fit the TRV , leave an upstairs rad til last is easiest way, I done my towel rad in bathroom as it has the bleed valves vertical on the top.
 
Fernox is good stuff,
But, if you have the system drained down, just pour it into one of the pipes before you fit the TRV , leave an upstairs rad til last is easiest way, I done my towel rad in bathroom as it has the bleed valves vertical on the top.
Towel rad is easiest to add inhibitor as steptoe mentioned just remove blank cap to add and open bleed valve on other side so to let air out when adding the inhibitor.
 
We changed the valves in bedroom a few months ago and just turned boiler and water off and swapped valve off, got a bit wet but wasn't too bad, when we replaced a radiator and valves in living room a couple of weeks ago we drained the system, much better way lol. We added inhibitor like others via the towel rad in bathroom. Make sure you put enough in for the number of rads in the system.
 
A few of my radiators don't get hot enough. They're cold at the bottom but ok at the stop.

One of them is fairly new, it was replaced by British Gas two years ago under their home "care" cover.

I thought I would try and sort this issue out on radiator first before I drain the system, and then do it on the others the same time as adding TRVs.

Yesterday I drained the 'new' radiator, took it outside and flushed it with a hosepipe whilst hitting it with a soft blow hammer. When I was draining it the water was black, whereas when I flushed it, the water become clear relatively quick.

Now, the radiator is a bit better than before, but its still not getting hot enough at the bottom. I've inspected the TRVs and I've noticed that on the radiators that work well I cannot touch the bottom of the TRV as its too hot. Whereas for the one that I flushed, the TRV is nowhere near as warm.

Would this mean I haven't flushed the radiator correct? Or that there is something wrong in the system? I'm wondering whether there is an airlock or something etc.
 
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A few of my radiators don't get hot enough. They're cold at the bottom but ok at the stop.

One of them is fairly new, it was replaced by British Gas two years ago under their home "care" cover.

I thought I would try and sort this issue out on radiator first before I drain the system, and then do it on the others the same time as adding TRVs.

Yesterday I drained the 'new' radiator, took it outside and flushed it with a hosepipe whilst hitting it with a soft blow hammer. When I was draining it the water was black, whereas when I flushed it, the water become clear relatively quick.

Now, the radiator is a bit better than before, but its still not getting hot enough at the bottom. I've inspected the TRVs and I've noticed that on the radiators that work well I cannot touch the bottom of the TRV as its too hot. Whereas for the one that I flushed, the TRV is nowhere near as warm.

Would this mean I haven't flushed the radiator correct? Or that there is something wrong in the system? I'm wondering whether there is an airlock or something etc.
I had a similar issue on the radiator furthest away from the boiler, it had been acting as a sediment collector of limescale etc with a normal flush it still remained cold at the bottom in kind of a arch shape.

Took it off again and dissolved 200gram of citric acid in hot water put that in and topped off radiator with hot water and left it overnight. Flushed it normally the following morning fitted and bled it problem gone.
 
A few of my radiators don't get hot enough. They're cold at the bottom but ok at the stop.

One of them is fairly new, it was replaced by British Gas two years ago under their home "care" cover.

I thought I would try and sort this issue out on radiator first before I drain the system, and then do it on the others the same time as adding TRVs.

Yesterday I drained the 'new' radiator, took it outside and flushed it with a hosepipe whilst hitting it with a soft blow hammer. When I was draining it the water was black, whereas when I flushed it, the water become clear relatively quick.

Now, the radiator is a bit better than before, but its still not getting hot enough at the bottom. I've inspected the TRVs and I've noticed that on the radiators that work well I cannot touch the bottom of the TRV as its too hot. Whereas for the one that I flushed, the TRV is nowhere near as warm.

Would this mean I haven't flushed the radiator correct? Or that there is something wrong in the system? I'm wondering whether there is an airlock or something etc.
depends on the trv type some are not bidirectional danfoss for example
and you need to remove trv head and there is part you turn to point arrow in direction of flow through radiator danfoss manual you can also buy system cleaner that you can add but you need to drain system once it has done its job and re add inhibitor.
 
I have to crack down some of my rads to get the ones furthest from the boiler to get hot , I turn the lockshield valve down on some rads close to boiler or rads in between boiler and colder ones . I would leave them open say half a turn , test it , then adjust another half a turn until they all work . Takes a bit of time while you wait for them to warm .
 
depends on the trv type some are not bidirectional danfoss for example
and you need to remove trv head and there is part you turn to point arrow in direction of flow through radiator danfoss manual you can also buy system cleaner that you can add but you need to drain system once it has done its job and re add inhibitor.

If I add cleaner to the whole system. Can I just add that into one radiator or do I need to drop it into the cold water tank in the loft?
 
If I add cleaner to the whole system. Can I just add that into one radiator or do I need to drop it into the cold water tank in the loft?
Adding it to one radiator won't do anything, the hot water is traveling around the whole system every time the heating comes on.
When you washed it out, how many times did you rinse it through with the hosepipe?
Sludge has a consistency of thick paint
 
Did you fill rad when flushing it and lift it side to side and up and down a few times to make sure you got everything out.
Does the rad heat the full way if you isolate all other rads to force water to that one radiator? If so could be a balancing issue or circulating pump not strong enough no more.
 
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