Motorised valve different types? Edited

tod4 · 25 Sep 2008

The saga continues.
I've had new motorised valve fitted. Since then I've had very little heat from the rads.
I've checked power to the valve and have taken the cover off to see what happens. When the HW is on the valve motor operates and the rads get hot. When the CH is on it doesn't move. None of the wiring has been touched although I have checked it.
I've come to the conclusion the valve is either the wrong type or its on upside down.
By this I mean (is this correct). When the HW comes on the valve should operate to direct water to the hot water tank. Normally it is not operated so water goes to the rads.
When I move the lever to manual I get the same effect as when the HW comes on the rads get hot but not as hot as they do when the valve is operated, checking this is becasue the valve doesn't move quit as much.
So should I get the plumber to put it on the other way up, or should I get him to get one that works the other way round to one I've got? In other words in to supply water to the rads when the motor is not working.
I hope that makes sense because it's driving me nuts.

By the way the valve is a Boss BMPV222, according the instructions on the info. sheet he ahs put it on the right way.

twgas · 25 Sep 2008

When the HW is on the valve motor operates and the rads get hot. When the HW is on it doesn't move.

can you check what you are saying !!!!!

seco services · 25 Sep 2008

confusing

tod4 · 25 Sep 2008

Sorry trying to do too much at the same time. Edited above

seco services · 25 Sep 2008

if you say the valve operates when hw on.
but don't move with heating its wired wrong.

useally with hw on the valve stays in the relaxed position heating closed.
hw off heating on the valve will motor across to close the hw port.

have you checked what colour wires are getting power when hw, heating are calling for heat.

Gasguru · 25 Sep 2008

The wiring is incorrect...in hot water mode only the valve motor should NOT operate.

D_Hailsham · 25 Sep 2008

The ports are marked: A, B and AB.

The AB port is the feed from the pump.
The A port goes to the central heating.
The B port goes to the HW cylinder.

If the valve is the correct way round and the valve is opening for Hot Water, then the valve is wrongly wired.

White goes to the output from the CH thermostat.
Grey goes to the HW stat OFF and the HW timer OFF
Orange goes to the boiler.

The HW ON from the stat goes to the boiler (same terminal as the orange).

When HW is required the valve should do nothing as port B is held open by a spring. When HW and CH are required the valve opens to mid-position (A and B ports open); and when CH only is required the A port opens completely.

tod4 · 26 Sep 2008

It is a mid position valve being used as a two position valve. The original has three wires the new has five. I phoned Siemens who make the new one and they told me how to wire it up. I didn't touch any of the wires in the connection box. I just cut the wires coming from it and connected the new valve to them. I had a plumber fit the valve and last night he told me it was direct replacement for the old valve.
When the CH is on there is no power to the valve
When the HW is on there is power to the valve.
No wiring has been changed or messed about with any where.
The only thing I saw that I thought was strange was that in the connection box the original wires were wired like this:
Green/yellow to the same connection as all the other green/yellows.
Brown from the valve to the same connection as all the blue wires.
Blue from the valve to a seperate connection, this has a wire coming from a small Siemens unit (that even they don't know what it is).
If I were to swap the blue and brown wires round what would happen?
I could check to see if there is a connection in the connection box that has power when the CH comes on but looking at the box there isn't a free connection, logic tells me it would be one on its own.

D_Hailsham · 26 Sep 2008

tod4 said:
It is a mid position valve being used as a two position valve.

So it is a Diverter valve, not a Mid-position. What is the model no of your valve? Is it a MA-V322C or a DA-V322C?

tod4 · 26 Sep 2008

Valve is a Boss BMPV222 or thats what it says on the leaflet.

seco services · 26 Sep 2008

thats a mid position valve

D_Hailsham · 26 Sep 2008

Why are you trying to use a mid-position valve as a diverter?

Mid-position valves are sprung loaded so the HW port is open; the CH port only opens when power is applied to the valve motor. Diverter valves are the other way round. The CH port is kept open by the spring and the HW port opens when power is applied. If you are trying to use a mid-position valve as a diverter, it will need to be installed the "wrong" way round, .i.e port A for HW and port B for CH.

What is the "small Siemens unit" you mentioned? Any part no etc on it?

Agile · 26 Sep 2008

D_Hailsham said:
Why are you trying to use a mid-position valve as a diverter?

Mid-position valves are sprung loaded so the HW port is open; the CH port only opens when power is applied to the valve motor. Diverter valves are the other way round. The CH port is kept open by the spring and the HW port opens when power is applied. If you are trying to use a mid-position valve as a diverter, it will need to be installed the "wrong" way round, .i.e port A for HW and port B for CH.

What is the "small Siemens unit" you mentioned? Any part no etc on it?

Its fine to use it as a two port ( although a little odd! ) as long as the HW port is used for connecting the heating. Powered to open just like a two port!

Tony

tod4 · 26 Sep 2008

Thats what I was told. The man at Siemans told me it is OK to use as you can connect it to be completely closed (spring) or completely open (motor). My problem is now it works (motor) when the HW is on.

D_Hailsham · 26 Sep 2008

tod4 said:
My problem is now it works (motor) when the HW is on.

So if the valve opens when HW is on but the rads get hot, the valve must be the wrong way round. It needs to be Port A to the HW cylinder and Port B to the radiators.

I looked back at you earlier topic and you gave the part no of the small Siemens unit as V23008-A0002-A100. A quick google and I discovered that this is a relay. The only reason I can think of for using this, is that the boiler needs volt free connections and the relay provides this.

Of course you would have had none of this hassle if the plumber had installed the correct valve.

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Motorised valve different types? Edited

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