Heat exchange from reflek flue

[sailor1924]

Originally Posted by Strait Shooter

I'd also like to know the vacuvent supplier should anyone know. I've searched with no luck so far.
Thanks in advance.

Vacu-Stack sorry, for wasting peoples time with the wrong name.

[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.

[sailor1924]

Originally Posted by Pauls

i looked on their website and didn't find a chimney coil diagram. I bought a Refleks several years ago and it came with the diagram showing the coil. if I can dig it out I'll scan and post it.

The Refleks website does show a set up for water heating systems using one of their water heaters, for both convective and pumped setups. They spec a minimum rise from the heater of 1" vertical in 20" horizontal for the water line.

Thanks in advance for the diagram if you can find it.
My biggest problem in the heating game is cold feet. The way this boat is configured is a pilot house upper saloon and a lower saloon where the heater is located. I'd really like to get some radiant heat down below the cabin sole or close to it. To have a consistent convective flow in my configuration, I think I would need an expansion tank, close to the overhead, all the way forward to overcome the height of the coil on the flue.

[sailor1924]

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 compromise.
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.
Below photo: 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.

[Pauls]

Thanks for the detailed reply. And those are beautiful boats, both yours and the others.

I looked for that diagram and cannot find it. It was simple, showing several turns of tubing around the flue, then a rising run to the radiator and a falling run return line back to the coils, with a header tank above everything.

I agree that the place you want the heat (and radiator) is low, just above the floorboards, and to do that a circulation pump seems necessary. Thanks again for the info.

[sailor1924]

Thanks for looking Paul.
I'm back on the Countess again having been ashore earlier in the winter and I just noticed I'm running two fans to try and get the heat to distribute a little more effectively. And the other thing I'm noticing is that without the system running for a while, it's taking the best part of a day and overnight to get the temperature up to an almost comfortable level. And my feet are still cold. And you could still hang meat in the forward compartment and head.
I'm remembering why I put a hydronic system together for the old boat and why I'm longing for one now.
I find these conversations online have jogged my memory and helped me to clarify why I made some of the decisions I made in the past and sharpened my attention to what I'd like to accomplish with this boat. So thanks to all who've participated.
And I'm working on installing the windlass, able to see my breath in the forepeak, and waiting for the winter to end.

[christhefish]

Another safety feature I was thinking about was a diesel shut off solenoid controlled by a temperature sensor on the flow pipe . I did manage to find a diagram in the reflek paperwork not very comprehensive will try to scan

[Phil70]

Have to agree with H cowl, I had one on my previous boat on the flue of my Glembring heater (like a Refleks) and this winter fitted a H cowl on my Narrow Boat. No issues with blow back no matter how windy it is.
Phil

[sailor1924]

Originally Posted by christhefish

Another safety feature I was thinking about was a diesel shut off solenoid controlled by a temperature sensor on the flow pipe . I did manage to find a diagram in the reflek paperwork not very comprehensive will try to scan

I have not installed a solenoid as I didn't want to be dependent on the electrics for safety, however I don't really know how the solenoids work. If they are normally closed then I think it's probably a good idea.
Also both of the heaters I've owned had a very simple melt out fuse in the metering valve that was designed to shut off the fuel flow if the heater "ran away" and overheated. The metering valve is not supposed to get hot only warm to the touch, I know Dickison has the same, and you should check if the Refleks has that feature.
I have installed a very loud smoke/fire/co2 alarm and sleep better for it.

[christhefish]

The reflek does have a thermal link , but I was concerned about the calorifer overheating . I know this will depend on the amount of windings I put around the flue this will be trial and error . should be fun over the next couple of months will keep you all informed

[Phil70]

Originally Posted by christhefish

The reflek does have a thermal link , but I was concerned about the calorifer overheating . I know this will depend on the amount of windings I put around the flue this will be trial and error . should be fun over the next couple of months will keep you all informed

You should be sort of OK provided your PRV on the calorifier is not jammed
The worst that can happen is you eject steam overboard and I reckon you would notice that
Phil