Can anyone recommend a 12 volt T or Y motorised valve?

[RigidRaider]

It's for diverting solar heated water to the coil downstairs once I've filled my upstairs cylinder to 60 degrees.

(Even now my 20 tube panel is heating the incoming mains water from 8 C to 40C and by June we will be getting 2.5 times the solar radiation we are getting now, so I'm going to have spare heat and will use the main house cylinder as the dump)

Have found this but it's pricey: http://www.baytree.co.uk/products/20P_3way.html

 

[oilhead]

£95 is not that expensive, even if you need another £30 or so for the valve body. You are getting a commercial standard, more reliable unit than a domestic valve. If it's in the house, why does it need to be 12volt?

 

[Fluffster]

Have a look at this site, they deal in water softeners that use 12v synchro motors which are the exact same size as the ones in heating valves.

Pete

http://www.wrekinwatersofteners.co.uk/wrekinwatersofteners/category_final.asp?department=Service Parts&category=Waterside Aquadial

 

[RigidRaider]

£95 is not that expensive, even if you need another £30 or so for the valve body. You are getting a commercial standard, more reliable unit than a domestic valve. If it's in the house, why does it need to be 12volt?

The differential controller runs off a 12v cellphone charger (really!) and knocks out 12v to power the valve.

 

[mickyg]

trouble is no one makes such a thing for domestic purposes, so anything you find will be commercial kit.....commercial = expensive. If you've found something for a ton then you probably not gonna get much cheaper tbh.

 

[oilhead]

Will your charger give enough current to operate the valve? I'm sure it will take more than millivolts. Better to consider switching a 12v relay to run a 240v valve.

 

[oilhead]

Meant to add: What do the manufacturers/suppliers of the control unit suggest?

 

[RigidRaider]

The controller can do 3.5 amps at 12 v, which is more than adequate for that 12v valve I linked.

Could also do it with a relay and 240v but why complicate things?

Latest news is that the bloke who imports the kit has contacted his Chinese supplier and is expecting to receive samples of an appropriate valve that he reckons will be around £50.

 

[oilhead]

looks an option, but what happens when you need spares and the importer has disappeared, or if the controller fails and is no longer available and you have to substitute?
A relay operated standard valve is much easier to adapt, and incorporating a relay is very little complication.

 

[RigidRaider]

I see your point but I want to avoid getting into 240 volts as it introduces all kinds of problems. The differential controller has an output for this very use and it will be simplicity itself to wire it up.

The system is so minimal and simple that it won't be hard to pull it apart and modify it in future years. In fact a couple of months after I'd built it I pulled most of it apart and rebuilt it because I saw ways in which I could improve the design. Isn't this what companies call R&D?

 

[Norcon]

Can also be done with a termovar AF fitted appropiately and no electrics involved....
http://www.navitron.org.uk/forum/index.php/topic,13228.0.html

 

[RigidRaider]

Hmmmm... that's interesting! However as somebody points out on the Navitron forum, you'd still need to find a way to keep the pump running. With a motorised valve actuated by the differential controller all that is sorted out for you.

 

[Norcon]

But why would a controller need the addition of an electrically operated mechanical 3 port valve in order to maintain the operation of the circulator?

Thats like saying I need a relay but I'll just fit an expensive three port actuater head instead.

 

[RigidRaider]

That thermostatic valve would be fantastic if it wasn't for the fact that the differential controller senses the temperature of the stored water rather than the liquid in circulation. In June I expect the liquid will be reaching 80 degrees or more as it carries heat from the panel to the coil. My idea is to fill one cylinder with water at 60 degrees then dump the excess heat in the second cylinder. The Termovar is a very neat device but lacks the element of control that I have with the differential controller sensing manifold, tank top and tank bottom temperatures. Once the attic tank reaches 60 the DC will open the valve to send the water into the downstairs tank.