Are my motorised valves spring returns?

[bcfcjwb1]

Hi,

I'm in the process of buying a Heatmiser PRT digital programmable thermostat. I have 2 choices available to me, a standard terminal or a changeover terminal.

I have absolutely no idea what a changeover terminal is, although I understand that if I have a valve that needs power to open and power to close then I need this option!

If it helps, I have a Megaflow system with 2 motorised valves - a Drayton and Sunvic. The PRT will replace a Drayton RTS1 manual thermostat.

Thanks

 

[gas4you]

Strange, Megaflo's are usually supplied with a Honeywell 2 port valve as standard.

The HW valve must be a sring return valve as this acts as a safety device if the boiler won't shut down and the water store gets too hot.

If the heating valve is the SunVic, then unless its the MOMO type it will be sprung return.

 

[ollski]

Check your clock to see if your heating off terminal is connected.

 

[bcfcjwb1]

Hi,

The Sunvic motorised valve is model is SZ2301F. It is installed on a horizontal pipe at the bottom of the Megaflow cylinder. I assume this is for the hot water?

The ACL-Drayton motorised valve is model is 779H335-30L10. It is installed on a vertical pipe on the wall of the airing cupboard. I assume this is for the heating?

How can I be sure that both of these valves do not require power to open and power to close? They do not state MOMO or spring return on the units.
Sorry if it's a daft question.

Thanks in advance.

 

[bcfcjwb1]

Will the fact that I have a Drayton RTS1 installed already give a clue.

ie Would an RTS1 be able to control a system where valves that require power to open and power to close were installed?

 

[bcfcjwb1]

Hoping to order this today, anyone?

 

[bcfcjwb1]

For the record, both of my motorised valves are spring return.