TRV

[mjtefc9]

Hi,

I have installed a wireless thermostat upstairs, but this means the main rad in the bedroom doesn't affect the thermostat and the room gets roasting!

Because the old stat was in this room the rad had no TRV on it.. how easy is it for me to fit a TRV to the rad now? I see lots of posts for replacing a TRV but this doesn't have any valves either side?

Thank you

Mark

 

[ianmcd]

post a pic of the rad,unless a very old rad it will have valves

 

[mjtefc9]

Hi ian..

Cheers mate

 

[ianmcd]

That is two danfoss Lockshield valves, just get a danfoss 15 mm TRV and it will be a straight swap, the cap on the top screws off (no water will come out) and inside there you will see an Allen head you turn that down that is how you close the valve

 

[mjtefc9]

That is two danfoss Lockshield valves, just get a danfoss 15 mm TRV and it will be a straight swap, the cap on the top screws off (no water will come out) and inside there you will see an Allen head you turn that down that is how you close the valve

Thank you Ian!

 

[mjtefc9]

https://www.screwfix.com/p/danfoss-ras-c-white-chrome-angled-trv-15mm-x/70871

This one?

 

[ianmcd]

https://www.screwfix.com/p/danfoss-ras-c-white-chrome-angled-trv-15mm-x/70871

This one?

yep that one will do it, but if that doesnt match the rest of the house then just get the same as the others , just be aware that some boilers need an external by-pass and its common to leave a radiator as yours is as the by-pass, its usually the bathroom one but if you have TRVs on all the other rads you might want to take the lockshield valve that you remove and just swap it with the bathroom valve

 

[mjtefc9]

Yeah they are all Danfoss.. the bathrooms have towel rads.. the boiler is a potterson promax 33 combi Erp

 

[ianmcd]

yes but do the towel rads have TRVs on them or is one the same as the bedroom rad ? your boiler doesnt need an external by pass as it has an internal one inbuilt but never does any harm to have one

 

[mjtefc9]

Thanks Ian.. yeah both have TRVs on.. so do I need to drain the rads or anything to swap a TRV? I'll take one off the hall rad as they can stay on

 

[ianmcd]

I wouldnt just close the end that you are not swapping, remove the pressure at the boiler and have towels down some water will come out as you are doing it but not a lot, you can drain everything if you want, but if you do remember to add inhibitor when re-filling, all depends on how confident you are, its an every day job to us and we dont panick when a little bit of water comes out , but as I say if you are more comfortable with it drained down then just do that, but it looks like you have what we call drop feeds, and the system hasnt been fitted properly as you should have drain down lockshields fitted on the ground floor rads, so you wont be able to drain them any way so just take the pressure off and use towels

 

[ericmark]

I wanted to add a TRV on a down stairs radiator, I expected loads of water to run out as I changed it, I ran a hose out of front door and opened drain but very little ran out, so positioned carpet washer to suck up any water split, and got everything ready for quick change, however the water split was very small, and it was clear, so I made sure I added inhibitor to radiator before refill. However in the past I have made a right mess trying to add TRV's but this time went like a dream.

I have also tried swapping the TRV heads for electronic types, I had all big ideas of adjusting each room temperature through the day, however I found although they controlled the room really well, I found rooms don't cool very fast, so the connection to PC with geofencing was a waste of money, but the better control being able to set at 18°C not just between 3 and 4 worked very well, once set.

I say once set, my problem was the installers have fitted the TRV's to the return pipes, they are bidirectional, however if on the feed it senses the heat from radiator quickly and compensates, but on the return whole radiator gets warm before it heats the TRV so the setting of the lock shield was critical so radiator did not heat up too quickly so the question after setting is. "Would the room have been controlled just as well with just the lock shield valve?" likely not, but with a TRV set to between 3 and 4 how does one know what temperature it is set to? So how do you know if the lock shield needs adjusting or the TRV?

 

[mjtefc9]

I wouldnt just close the end that you are not swapping, remove the pressure at the boiler and have towels down some water will come out as you are doing it but not a lot, you can drain everything if you want, but if you do remember to add inhibitor when re-filling, all depends on how confident you are, its an every day job to us and we dont panick when a little bit of water comes out , but as I say if you are more comfortable with it drained down then just do that, but it looks like you have what we call drop feeds, and the system hasnt been fitted properly as you should have drain down lockshields fitted on the ground floor rads, so you wont be able to drain them any way so just take the pressure off and use towels

Ian ,

Can I just take the cap of the valve and screw this on : https://www.screwfix.com/p/danfoss-...-x/5448v#product_additional_details_container

 

[ianmcd]

nope that is a kit of two valves the lockshield which you have and the other is the TRV with a decorators cap on it which is removed and the sensor attached