Changing radiator valve to TRV correct procedure

enfant terrible

Hi guys,

The radiator is located downstairs.

For draining the system should I open all the air valves, in all the radiators in the house before draining?

Then after fitting TRV should I start bleeding the radiators from upstairs?

Thanks

John.G

enfant terrible wrote: »

Hi guys,

The radiator is located downstairs.

For draining the system should I open all the air valves, in all the radiators in the house before draining?

Then after fitting TRV should I start bleeding the radiators from upstairs?

Thanks

You can replace it without draining down any of the other rads, just the rad that you are replacing the TRV on and the system (pipework) contents. Isolate all the other rads by shutting their TRVs (make a note of their index setting first) and the lockshield valve(s), on some you may have to remove the plastic "knob" and shut them off with a adjustable spanner. The only drawback of doing this is that your system may have been balanced by a plumber at some stage by throttling the lockshield valves on various rads, if you know/think that this has been done then you are better off draining down the whole system, open all the vents as you are draining down. When refilling, I would leave the rad air vents fully open, fill the system very slowly and shut off the vents as water appears from each one, put a sheet of newspaper under each one before you start refilling. Dont forget to add inhibitor before you start refilling, either into the header tank (vented system) or into one of the rads (sealed system).

enfant terrible

John.G wrote: »

You can replace it without draining down any of the other rads, just the rad that you are replacing the TRV on and the system (pipework) contents. Isolate all the other rads by shutting their TRVs (make a note of their index setting first) and the lockshield valve(s), on some you may have to remove the plastic "knob" and shut them off with a adjustable spanner. The only drawback of doing this is that your system may have been balanced by a plumber at some stage by throttling the lockshield valves on various rads, if you know/think that this has been done then you are better off draining down the whole system, open all the vents as you are draining down. When refilling, I would leave the rad air vents fully open, fill the system very slowly and shut off the vents as water appears from each one, put a sheet of newspaper under each one before you start refilling. Dont forget to add inhibitor before you start refilling, either into the header tank (vented system) or into one of the rads (sealed system).

Cheers John will drain it and follow your instructions

rightjob!

Do not even think about having all rad vents open when refilling the system,you will be running around like a mad man when refilling and make a mess.

To change the rad valve,isolate the filling loop up or gate valve in your hotpress.
Close both sides of the radiator that you need to work on.
Remove the radiator and place it aside.
Attach a hose to the rad valve you want to change and drain it from there.
When the system is drained swap the valve for the new one,refit the rad and fill the system up again.
Vent all the rads and turn the boiler on to check all are heating up.