Water Heater...

Re: Water Heater...

The problem with liquid under high pressure in a sealed bottle, such as LPG, is that the valve on top, also contains the over pressure release valve, the "blow off". If the cylinder is upright and for whatever reason the pressure exceeds the limit (overfilled or over heated etc), the blow of opens and releases vapor only, dropping the pressure back to the safe zone. If that same cylinder is on it's side and the blow off lets go, two things can occur. One, instead of safely releasing vapor, it sprays liquid, which in the case of LPG, boils at minus 40 C when no longer under pressure, causing instant and severe damage to human, or any other flesh it comes in contact with. And two, the blow off is designed to release enough VAPOR to maintain safe pressure, but liquid may not pass through the blow off rapidly enough to ensure the cylinder won't get dangerously over pressured. For these reasons, it is against the law in Nova Scotia to transport propane cylinders, or any other such cylinder containing a dangerous liquid under pressure and with a blow off on the top of the cylinder, in any position other than secured in an upright position. Even if the valve gets broken off, escaping vapor from an upright cylinder produces less of a "kick" than does liquid that might be released from a cylinder on it's side.

Re: Water Heater..

mtdoc wrote: »

There seems to be very little about how to do this on the web.

try searching 'range boiler'
read a lot... they can explode!

mtdoc wrote: »

A coil through our woodstove for the winter and solar in the summer, with on demand propane as backup. Any tips would be welcome.- especially about your wooddstove setup.

I have set up at least a dozen woodstove range boilers. All of my systems have been thermosiphons.

My first several systems were external to the woodstove. They worked very well, but need 2-3 feet of copper.

When I started building internal systems, I used all brass or stainless (just a 5-8 inches).

In all my systems I put pressure temperature relief valves on both input and output of the heating coil (not literally a coil).

If you have hard water, they can become obstructed.

--vtMaps

Re: Water Heater...

Thanks for the pointers vtmaps and Icarus. Understood about the need for good pressure relief valves and the explosive potential if not done right!

I'm not sure a pure thermosiphon will work for my situation. Current utility room with current water heater and on demand boiler/expansion tank for in-floor heating is located in basement - below the wood stove. Any experience using circulating pumps?

I'm a total noob when it comes to all but the most basic plumbing.. Will need to find a plumber locally who is willing to help. I'm not sure any nearby have experience with this - and especially with combining it with solar hot water.

There's a fair number of people with woodstoves here but no where near the number as in Vermont. I love Vermont! I lived just outside of Burlington for 4 years. Nothing like burning New England hardwoods in a good Vermont Castings stove. The Doug Fir here just does not last through the night like a stove full of Vermont maple will.

Re: Water Heater...

mtdoc wrote: »

Thanks for the pointers vtmaps and Icarus. Understood about the need for good pressure relief valves and the explosive potential if not done right!

I'm not sure a pure thermosiphon will work for my situation. Current utility room with current water heater and on demand boiler/expansion tank for in-floor heating is located in basement - below the wood stove. Any experience using circulating pumps?

I have no experience with pumps. You could do a 'hybrid' system... thermosiphon to a tank by the stove and use a pump to move hot water from it to the basement tank. If the tank by the stove is uninsulated you will add a measure of safety to the system because if the pump fails the uninsulated tank will be a radiator. If you size it right the fire will go out before the pressure-temp valve blows.

--vtMaps