Originally Posted by Pauls
Hey 1924, I wanted to ask you what was the incline, ie rate of rise, on the flue heated system you had that required 20 minutes of pumping before it would flow convectively? I'd like to understand what design features might be required to eliminate the need for pumping.
I think in trying to remember the details of the system, I'm going back to 1990 so a bit hazy, I paid no attention to rise and run as I simply wanted to put the convectors (radiators) where I wanted them. It was a 60' ketch
with five compartments on two levels and I was completely willing to pay the cost in electric consumption
for have an adequate heating system in NY winters. That system had coils in the firebox and would create steam really quickly if there was no water movement.
After some mistakes
and boil outs even with the pump
, I found that the system worked, if, I could purge all of the air from the system. Which meant installing air release valves at the end points and high points where the loop would change direction, and having a header expansion tank with enough liquid to resupply the system when a bubble would arrive at the tank and vent the system. I found after an initial system start up when air always needed to be vented, running the pump
and establishing the flow, a convective flow would establish itself and I could shut off the pump. I was puzzled at first about where the air came from, I assume that the air in the system was just from air dissolved in the liquid and would reappear whenever the system was down and cooled off.
I never hooked the system into the engine cooling
system as I had a tankless water heater and didn't think there was enough benefit for the risk of an engine
So looking this over; the short answer is I think any pressurized system would probably work
but steam happens really quickly and will pop the connections. So the height and location of the expansion tank is probably the most critical decision mine was about 4' above the stove
in the pilothouse. The relative gravity feed changes constantly when you're underway and if a system is to be used while underway that could be a consideration. All in all I think that the electrical consumption
of a small 12 volt circulating pump is probably a valuable contribution and not too costly for the possible benefit. And I stated for my installation
It wouldn't have worked otherwise.
I had two friends, who, I discovered had radiators and diesel
heaters. Both were set up similar to the way I describe mine. I might have saved some time and agita if I'd looked at their installations before reinventing the wheel
: My old boat
on the right, the center schooner, is one of the friends I mentioned above, had an oil
furnace with radiators he ran his pump full time, on the far left the ketch
had a coal stove