3 port diverter valve - is this correct?

[LaserMark]

Hi

I just bought a new Siemens/Landis 3 port diverter valve to replace the Switchmaster valve in our heating system that has finally expired after 20 years.

I thought I would check it works OK before installing it, so after wiring it in I observed the position of the valve ( its like a rubber wedge) while changing the demand for heating and hot water.

With CH demand but no HW demand the CH port is fully open. With HW demand but no CH demand the HW port is fully open. So far so good. But with CH demand AND HW demand the valve does not go to exactly mid point. I would estimate the valve goes to a position that is 60% CH and 40% HW. Is this how these vlves are set up normally or is the valve faulty?

I can imagine that it would be an advantage to operate like this because the CH loop will require greater flow than the HW loop. But is this how it should be?

I believe the 'mid' position is set by microswitches, are these adjustable?

Thanks

Mark

[cynic]

Should not be a problem - it means the heating circuit will have a bigger share of the available flow from the pump.

No

[Roger Mills]

All the valves I've seen move through 90 degrees from HW to CH - with the mid-position being at 45 degrees.

Sounds like someone has designed an 'improvement' into yours which gives a bit more flow to the CH than to the HW when both are demanded at the same time. I doubt whether it's a fault - it actually sounds like quite a good idea.

Did it come with a leaflet which describes its operation? If so, what does

*that* say?

[LaserMark]

Unfortunately the instruction leaflet is rather vague and just has the wiring diagram and port positions. Can't find it on the web either the box says Landis & Staefa but the valve itself is branded Siemens. Model no appears to be MA-V322C. Think I'll just give it a try, should soon be apparent if the HW is starved of flow.

[Phil Addison]

Landis & Staefa is now part of Siemens Building Technologies, and not too easy to find. There is what might be a similar model to yours here; CMV? 22 and 28mm 3-port motorised valves.

or long url a diagram showing a CMV322 here

see much data, but there are phone numbers Residential Technical Helpdesk: 0870 850 0184 General enquiries: 01784 412564

Phil

[Roger Mills]

> and a diagram showing a CMV322 here

The literature refers to a 'wedge' type actuator. Anyone know what that means?

[Phil Addison]

>

>

Where did you find that literature Roger? I couldn't find anything further on that site. Mark says of his "its like a rubber wedge".

Phil

Phil The uk.d-i-y FAQ is at

Google uk.d-i-y archive is at NOSPAM from address to email me

[Roger Mills]

I was referring to the second reference which you gave. If you click on the Flow Control bit, it shows pictures of 2 and 3 port valves, with a list of features. 'Wedge type adtuator' is one of the features listed.

[Phil Addison]

Ahh, right. Saw those... just glanced and went looking for the detailed download - nowt there!! Siemens have seriously dumbed down the old Landis & Gyr/Staefa site.

Phil