3-PORT MID POSITION VALVE REMOVAL/REPLACEMENT PROCEDURE ....

[stevehayes]

ok i need a plumber or someone who knows how to do this to tell me if this is correct:!!

To remove and replace a 3-port mid-position motorized valve is this the correct procedure:

1) TURN OFF MY BOILER (at the programmer)
2) TURN OFF THE MAINS SUPPLY TO MY FEED & EXPANSION CISTERN
3) DRAIN THE PRIMARY CIRCUIT
4) REMOVE THE COMPRESSION NUTS TO THE MOTORIZED VALVE, REMOVE AND REPLACE WITH NEW ONE



If this is correct I shall be happy as I am replacing mine at the weekend-or hoping to!!



Thanks so much for your help AGAIN!! It is very much appreciated!

 

[stevehayes]

I've just remembered that the electric supply to the valve needs to be isolated before I remove it! How is this done-with the immersion heater you take the fuse out of the switched spur. But there's a big screwed plastic cover which wires from the pump, cylinder thermostat and motorized valve all go! Do I remove this to take out the fuse??!!!

 

[Rob]

Yes thats pretty much it when changing a MV.

As for the electrics a fused spur should control your heating system including MV. This is where you need to be sure you've done it properly. Especially if your opening up the wiring centre.

 

[stevehayes]

ok thanks for your help. The thing with the electrics is the im mersion heater has it's own switched unit but the other electrical opponents, ie pump, motorized valve, cylinder thermostat are all joined to one box with no switch! Do I unscrew the cover ?? I don't wanna get it wrong!!!!

 

[uselessFCUK]

Obviously a cool system is safer to work on so switch water + CH to off in advance and allow the pump to stop on its own should it have a pump run-on feature, as expected.

Depending on the location of your MV (as in the first floor) would you really need to completely drain the whole system or to just below the MV assuming upstairs rads are shut-off?

Put the MV into manual mode if it has a lever on the side to move the valve into mid position. Refill system with the new valve in mid position.

The wiring center should only have mains power from a fused spur located at/near the boiler that supplies the boiler - so switch off, pull the fuse then test for any power at the wiring center. If not then isolate accordingly at your electrical consumer unit.

I'm sure someone will kindly correct any flaws in my input.

 

[LUNAT]

HI

make a note of the wires ( position)before disconnecting them
so when reconnecting them makes easier