Replacing Landis diverter valve

[timd157]

My ch system has been in for 15 years but is serviced regularly.
The boiler is a Potterton Suprima 30-80. Honeywell L641A cyl stat;
Siemens RWB2 programmer: Landis MA-V322 three port diverter valve.
I have no Room stats but each rad has a TRV fitted.
I have a problem with the domestic hot water, it gets scalding hot. I have changed the Cylinder stat to the one shown above, but it doesn't make any difference. I cannot see any operating movement on the diverter valve lever but it is loose and sloppy and no spring resistance. I suspect that is the problem.
Can I replace it with a Honeywell one which I understand is better?
Which 3 port valve would you recommend for my system?
Would the 22mm connection threads be compatible?
Do I need a room stat in my situation?
Hope that makes sense
Timd

 

[jackthom]

Can you try switching off the mains power to the heating system?

With no power the 3 port valve should spring back to it's rest position and the lever should then feel more resistant to being moved.

If it is still loose the valve or it's actuator is stuck, in which case it may be possible to get it freed up without having to drain the system, or you could certainly replace it with the Honeywell V4073A.

You should definitely have a room thermostat somewhere in the living area of your house. It will give you more control and could help save a lot of money on gas.

 

[timd157]

Thanks Jackthom
Will the threads of the Honeywell be the same as the present ones to make a straight change?
I note what you say about having a roomstat. How will that work. with all the TRV's and where would be the best place to site it?
What about wireless roomstats, are they any good for this situation.

 

[jackthom]

I'm not sure but there's a good chance the threads on the Honeywell will be the same.
If you do have to remove the old nuts and olives, Screwfix sell an olive pulling tool which should make it a lot easier.

There's also the danger that the new valve won't have exactly the same dimensions as the old one and the pipework may need a little flexibility of movement to take up any slack.

If you have no wiring installed for a room thermostat then a wireless one would be a good idea. They generally go in the lounge or hallway and the TRV head should be removed from the radiator in that location.

 

[willingz]

Landis MA-V322 three port diverter valve.
Can I replace it with a Honeywell one which I understand is better?
Which 3 port valve would you recommend for my system?

Siemens (who took over Landis) make a direct replacement - CMV 322.
I fitted one in 2012 very easily. Fitting is identical to the L&G and design improved as CMV 322 has detachable head. Also it was very reasonably priced.

 

[willingz]

I'm not good at sending messages. My first three lines were supposed to be selective quotes from OP.