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Discuss Advice on 3 port motorised valve? - I have an unusual wiring requirement in the Valves & Taps area at

  1. coldpipe

    coldpipe New Member

    Are there any 3 port motorised valves (preferable cheap) that do not require a constant mains current to flow when the value is either open or closed (ie it just needs current while actually opening or closing)?

    I'm trying to cobble together something for a small diesel heater to be used in a canal boat heating a hot tank and/or radiators. The boat runs on 12 volt and 12v motorised valves are impossible to come by so I'm going to use a small 12v to 240v mains inverter to drive the valve.

    As most valves are 5w I'd rather not have the inverter running and supplying 5w all the time the valve is open. So my idea was to fix the wiring so that when the valve needs opening or closing the inverter is switched on, the appropriate wire made live in the usual manner and then the inverter is switch off again once the valve has changed position.

    (The rest of the control logic I can do all in 12v)
  2. rpm

    rpm Trusted Plumber Top Contributor!!

    Be careful that what you cobble together doesn`t effect your boat insurance coldpipe.
    (Soon to be boat owner).
  3. Ric2013

    Ric2013 Plumber Top Contributor!!

    Well, you could use an S plan instead of a Y plan, and use a Cyltrol on the hot water side, and a RAVI, or a TRV on the heating side. Comes at a cost, mind.
    Else, you'll probably end up rigging some kind of motor to a lever spherical valves in such a way as that, once the valve is open, the power is diconnected, (much the same way as car wiper motors traditionally kept going until the wipers were parked and then stopped (as the permanent live was designed to be disconnected from the motor when in the parked position), as I discovered from careful observation of a Citroen Dyane wiper assembly).
  4. coldpipe

    coldpipe New Member

    It shouldn't do. It's all standard plumbing stuff. They only oddity is finding a valve that does not draw current all the time (like the spring return ones do). Doing so will tend to flatten the batteries faster by drawing 5w all the time the heater is on, in addition to that used by the heater and pump itself
  5. quality

    quality Plumber GSR

  6. coldpipe

    coldpipe New Member

    I thought about doing that with the lever ball valves but by the time I'd bought strong enough actuators to turn them I might as well pay for a normal 3 port valve and run it from 240v. The spring return motorised valves need a constant current though them so I was looking for a valve that doesn't.
    I'm sure I've used non spring return valves in my house in the past ie ones that need a current to open and a current to close but I can't seem to find them now
  7. Gasmk1

    Gasmk1 GSR

    if you are clever you may be able to do something with the normal motorised valves
  8. rpm

    rpm Trusted Plumber Top Contributor!!

    Sorry to divert (pun meant), can I ask what/which diesel heater are you using coldpipe.?
  9. coldpipe

    coldpipe New Member

    It's a Webasto Thermo Top C (17,000 Btu/h)
    • Informative Informative x 1
  10. coldpipe

    coldpipe New Member

    Thanks for all the advice from everyone.

    @"quality"I hadn't thought of using rotary valves. The eseb ones look good but will be expensive with an actuator - and I still will need an inverter.

    However acting on that advice though I've finally gone for a manual solution (at least for the moment) and bought one of these Rega Diverta 3 Port Manual Selector Valve 22Mm Three Way Diverter Control - Unvented Components Europe, the UK's leader in unvented heating spares - Specialists in plumbing & heating spares

    That way the hot water / heating ratio can be selected and modified 'on demand' I'll put in a simple digital thermometer to show the calorifier temperature so it will be easy to see when its time to dump the boiler output into the hot water. How often that will be will depend upon when the boat's engine was last run as that also heats the water via a second indirect coil in the calorifier
  11. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    what ever you do dont forget about supply air / ventilation
    • Agree Agree x 1
  12. coldpipe

    coldpipe New Member

    No problem, it's going in the engine bay with the exhaust going outside via an existing vent
  13. rpm

    rpm Trusted Plumber Top Contributor!!

    What you got bud, trad, semi trad?
  14. coldpipe

    coldpipe New Member

    It's actually my son who has recently bought it to live in (I'm just doing a lot of the work to renovate it !). I think it is called a cruiser style stern, wide beam canal boat, 50 ft long. Built as a live in boat but the previous owner had strange tastes in colour and layout and only half finished things like the heating. It's fun doing stuff but a bit of a pain when everything you want is 'special' for marine use. Even when trying to get a car starter battery for the bow thruster in Halfords, they couldn't tell me the cold cranking amp ratings of what they sold unless I knew what car it was for!
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