Advice needed for diesel heater install

[Bill O]

Originally Posted by SV__Grace

Very intriguing idea to use the water heating coils to hydronically heat a radiator in another cabin. Thanks!

Any idea if the water or coolant will be hot enough to heat a radiator in a 35 foot run of hose?

The better you insulate the pipe/hose, the hotter the coolant will be when it gets to the exchanger.

I like the idea, but no free lunch for energy usage. Depending on the relative height of the coils to the heat exchanger, you may need a water pump to move the water to the aft cabin. Also dependent on the type of heat exchanger, you may have a blower fan. Both aren't deal breakers in my book, but something to consider.

[SV__Grace]

Originally Posted by MJH

The September 2020 issue of Practical Sailor has five pages dealing with cabin ventilation. It might clarify where you need to place your emphasis.~ ~ _/) ~ ~ MJH

Thanks MJH, this article has some good info and illustrations.

The small aft cockpit sailboats in the illustration show two zones- forward and aft, and each zone being a circle of intake and exhaust.

Things get more complicated with a larger center cockpit pilothouse salon but the idea of creating a circle should still apply.

So I'm thinking to do the following-

Create more positive pressure forward by directing the 4 day/night solar vents to intake (they currently exhaust), including the two in the pilothouse salon.

Create more negative pressure in the aft cabin by adding an exhaust fan to compensate for when the solar fan doesn't work, and crack an opening port if needed.

The unknown is the raised pilothouse salon and companionway hatch between the forward and aft areas. Heated air rises and may get directed out the drafty hatch (unless sealed/weatherproofed) before being sucked by negative pressure towards the aft.

Hence my thought was to use a fan in the salon to direct air more aggressively to the aft area.

Please check my thinking on this!

Suggestions for creating one big air circulation circle instead of 3? (one in each zone).

[NorthCoastJoe]

If you go the hot-water route use 1/2" Oxygen barrier PEX tubing and a small 12-volt circulator pump. I use 1/2" PEX tubing on some very long runs, 150' round trip, in houses with no problem. You can pick up a 12-volt circulator pump for around $20. It does not need to be a big pump in a closed-loop system. For my home solar hot water, we use a cheap small 12-volt pump that draws about 1 amp and it handles it well. In summer water temperatures reach over 200 degrees F. Also put an expansion tank in the closed-loop and a way to top it up. Should not be hard to do if you use Shark Bite fittings or borrow a crimp tool.

If you go with moving air use a small 12-volt bilge blower. Blowers move air through ducting so you could duct it where you want it to go. Fans seem like they will move air but not where you want it.