Motorised Valve

[VJG]

I have recently moved house and discovered the actuator to the motorised valve on the pipe to my hot water cylinder is missing. This does not appear to present a problem!

Does the actuator really need to be replaced?

 

[45yearsagasman]

The actuator when correctly fitted and wired in will control the temp of the water in your cylinder and should interlock with the boiler,shutting it off when the cylinder stat is satisfied.

 

[VJG]

The actuator when correctly fitted and wired in will control the temp of the water in your cylinder and should interlock with the boiler,shutting it off when the cylinder stat is satisfied.

I had thought the cylinder stat controlled the temp in the cylinder. Is there a problem if i dont replace the actuater?

 

[45yearsagasman]

The cyl stat does indeed control the water temp by closing the motorised valve and shutting down the boiler.Describe other system controls you may have.

 

[VJG]

The cyl stat does indeed control the water temp by closing the motorised valve and shutting down the boiler.Describe other system controls you may have.

There is a motorised valve on the heating pipes to radiators and it is ok. There has not been an actuater on the motorised valve to cylinder for months. The valve itself is open constantly ie vertical.

 

[45yearsagasman]

Has the act been removed completely including the wiring?

 

[VJG]

Has the act been removed completely including the wiring?

Yes. The only thing on the pipe is the valve which i can turn with fingers if i want to.
Thanks by the way.

 

[45yearsagasman]

It does sound like you used to have an S Plan system but not anymore.

 

[VJG]

It does sound like you used to have an S Plan system but not anymore.

You've lost me there!

 

[JohnD]

An S plan has a boiler feed to the cylinder, and a boiler feed to the radiators. When either calls for heat, the relevant valve will be opened and the boiler will fire. if the valve to the cylinder is contantly open, heat will keep going to the cylinder even when it is hot enough, or too hot, as long as the boiler is firing.

this may cause the hot taps to be scalding, and it may cause the radiators to be cooler than you want, and slow to warm up.

 

[VJG]

An S plan has a boiler feed to the cylinder, and a boiler feed to the radiators. When either calls for heat, the relevant valve will be opened and the boiler will fire. if the valve to the cylinder is contantly open, heat will keep going to the cylinder even when it is hot enough, or too hot, as long as the boiler is firing.

this may cause the hot taps to be scalding, and it may cause the radiators to be cooler than you want, and slow to warm up.

Thanks. In the situation you describe will the cylinder stat stop the boiler when the cylinder reaches 60 degrees (its set position) resulting in the heat stopping to the radiators too?
Secondly, it appears i need to fit a new actuator to replace the missing one. Can you advise re wiring or where i can find advice re connecting it. I am ok with electrics and have a multimeter.

 

[JohnD]

the valve and thermostat wiring to the pump and boiler is (supposed to be) designed so that the boiler and pump run as long as either or both thermostats are calling for heat. When one of them is satisfied, it closes its motorised valve and hands over control to the other.

However this is not really my topic. You can get a wiring diagram from Honeywell or ACL Drayton or whoever makes your programmer (and preferably valves are the same brand as this makes it easier to follow)

If you want to see if it is correct, start by drawing up the various electrical components, and the colours of wires they have, then you can compare it to a manufacturer's diagram. The motorised head actuator has a number of wires of different colours. If you are fixing it yourself you will find it easier if you use a wiring centre to take all the wires to; and use the correct colours of wires per the diagram.

I did one myself with the help of experts on this forum, and found it quite difficult to get to grips with, although once you understand it all, it seems perfectly straightforward.

 

[VJG]

the valve and thermostat wiring to the pump and boiler is (supposed to be) designed so that the boiler and pump run as long as either or both thermostats are calling for heat. When one of them is satisfied, it closes its motorised valve and hands over control to the other.

However this is not really my topic. You can get a wiring diagram from Honeywell or ACL Drayton or whoever makes your programmer (and preferably valves are the same brand as this makes it easier to follow)

If you want to see if it is correct, start by drawing up the various electrical components, and the colours of wires they have, then you can compare it to a manufacturer's diagram. The motorised head actuator has a number of wires of different colours. If you are fixing it yourself you will find it easier if you use a wiring centre to take all the wires to; and use the correct colours of wires per the diagram.

Thanks John. I appear to have been misinformed by my boiler service man who told me no need to replace the actuater ie leave the valve open.

 

[spraggo]

Thanks. In the situation you describe will the cylinder stat stop the boiler when the cylinder reaches 60 degrees (its set position) resulting in the heat stopping to the radiators too?
Secondly, it appears i need to fit a new actuator to replace the missing one. Can you advise re wiring or where i can find advice re connecting it. I am ok with electrics and have a multimeter.

No, because the HW actuator which is controlled by the cyl stat is missing. In the past I have come across this situation where the head has been removed because the spindle in the valve body has ceased, causing the MV being unable to turn it and rather than draining the system to fit a new valve, the actuator had been removed and the valve set to open by hand. So it would be wise for you to check that this spindle can be turned freely before you proceed fitting a new actuator.

 

[VJG]

Thanks. In the situation you describe will the cylinder stat stop the boiler when the cylinder reaches 60 degrees (its set position) resulting in the heat stopping to the radiators too?
Secondly, it appears i need to fit a new actuator to replace the missing one. Can you advise re wiring or where i can find advice re connecting it. I am ok with electrics and have a multimeter.

No, because the HW actuator which is controlled by the cyl stat is missing. In the past I have come across this situation where the head has been removed because the spindle in the valve body has ceased, causing the MV being unable to turn it and rather than draining the system to fit a new valve, the actuator had been removed and the valve set to open by hand. So it would be wise for you to check that this spindle can be turned freely before you proceed fitting a new actuator.

Thanks. The spindle can b easily turned with fingers ie little resistance. In the examples you found did you fit a new one or leave it (the MV) in the open position. My question originally was can it be left like that? The replies so far seem to be saying it should be replaced.