Changing a radiator in two zone house.

[Herny80]

Amateur DIYer here. I need to move and replace a radiator in the upstairs bathroom. The house has two thermostats one for downstairs and one for upstairs. My question is. Do I need to drain the entire system from the downstairs rad by the door that has the little spout that you can connect a hose? or do I just drain from the upstairs rad which also has a drainage spout. I wasn’t sure if I drain from downstairs would upstairs still remain full?

Thank you.

 

[terryplumb]

Drain from ground floor rad and manually latch the zone valves open.

 

[Madrab]

Is the system sealed, i.e. is it pressurised? Where are you moving the rad to?

If it's sealed and you are just replacing the rad then you don't need to drain down. System just needs depressurised and then the rad in question drained down.

 

[Herny80]

Thank you for the reply. It’s a pressurised system. I only need to move it probably 12inches to the left. Was going to change the radiator and the valves to something more modern. Would I need to drain the system to change the valves?

If it makes it easier they are fitted with plastic push fit pipes. I am struggling to see how you even disconnect the pipe from the valves as they are pushed in. Do you need to cut them?

 

[terryplumb]

If you are cutting into and extending pipework you should drain down.
At least to a level lower than the pipework you are working on.

 

[Herny80]

Thank you.

 

[Madrab]

If all I was doing was changing the pipework, upstairs for one rad I wouldn't ever fully drain down. If it's upstairs then I don't see the benefit of draining the whole thing down. Certainly would drain the pipework to the level that was being worked on. If it was the main pipework at the lowest level then yes drain to that level but even then I still wouldn't drain the other rads though.

If the rads are empty for more than a day then they will start to rust and then all that does is start to introduce corrosion into the system.