i'm fitting a central heating type system into my motorhome (eberspacher water heater for the boiler, calorifier for the hot water cylinder, and a few radiators, pipes and valves)
I want to set it up like a home central heating and hot water system, digital programmer, tank stat, room stat, 3 way mid position valve on the output from the boiler to divert the hot water through the calorifier to heat the water for taps, shower and washer, throug hthe radiators to heat the van, or both if the tank and room stat's call for heat.
Problem is the van runs every electrical load on 12 volts, and whilst the digital programmer and stats are no problems iwth that, the 3 way valve is.
I thought it'd be a simple thing to get a 3 way valve with a 12 volt DC motor in it, but apparantly not, only one's i've found are for swimming pools, and thus have 5 inch ports (even i don't think i could bush them down to the 12mm and 15mm pipes used in the van) and they cost as much as the eberspacher heater cost me (which is not cheap to say the least)
Don't suppose anyone knows of a 12 volt powered 3 way valve for central heating/hot water??