24V DC hot water circulation pump

[David Mack]

What's the problem with returning the water to the fresh water tank - I could re-route the return water to a sump box or an overboard drain, but that would defeat one of the purposes of it (to save water)

 

Since your pump will inevitably circulate more hot water than is needed just to fill the pipe, you will be wasting heat by putting it back into the cold tank. Why not just connect the return line into the inlet connection of the calorifier (between the non-return valve and calorifier tank). That way the hot water is retained in the hot water system, and you don't put heated water back into the (potable) cold water tank.

[singleprop]

There is a timer on the valve - I will need to find out how many seconds it has to stay open before hot water comes out, this will reduce the "hot water waste".

 

Returning the hot water to the calorifier tank might be problematic due to the water pressure from the accumulator tank - the calorifier tank has the same pressure as the accumulator so opening a valve with the same pressure on both sides of the valve will not create a flow. I'm using the differential pressure between the accumulator and the unpressurised water tank to create this flow.

Edited February 9, 2014 by singleprop

[Kieron G]

Hi, a good place to get a cheap 24v circulation pump could be from a commercial vehicle breakers that deals with busses. On double deckers they use ( or used to ) a 24v pump to get the water up to the top deck for heating.

Edited February 9, 2014 by Fitter kieron