Hydronic heat?

[tinbender]

I have a Tomcat, and am considering adding a Planar diesel water heater. My thinking is hydronic heat in head, under berth , switching my tank type hot water heater into one that has heat exchanger inside it like used with inboard engines. Running the water from the Planar through the tank heater to create my domestic hot water. Probably a bus type heater plumbed to the Planar to furnish the cabin heat and defrost. Anyone done it? Pros or cons? I have installed hydronic heat in 2 houses , 2 shops and a greenhouse. Installation I will do , so cost is components only.

[thataway]

hI designed and built my own hydronic circulating hot water system. We used a on the road truck unit (I am blocking on the name of the Canadian firebox/pump currently). it was 45,000 BTU, fuel pump, air compressor to help atomize the diesel & blower for the forced draft exhaust. (Also brought in external air for combustion chamber). We had 3 radiators, one in the main saloon, one in the forward stateroom and one into aft stateroom. These were copper tubing finned type with a computer fan on a thermostat. The fans came on at a certain temperature you would set. The circulating water was 150* and the unit would cycle on and off in the limits of 145 to 155 degrees. We didn't include the water heater, since we ran the genes every day for making water, charging batteries, etc--or it ran off the main engine. There are copper coils under the floor in the heats, and in the wet hanging locker. Each head had a towel rack with coils behind it. It worked very well in AK.

Needless to say this is a unit far greater in capacity than you would need. I probably would put one fan powered radiator in the Foreward bunk and one in the main saloon.

We also ran a 25,000 BTU "Red Dot" radiator off the main engine--that was in series with the water heater. It would heat the main saloon, and if the hatch was open, the cockpit.

[thataway]

Beyond my edit limit:
Advantages in a boat for hydronic heat, is that you only run1/2 to 3/4" tubing, instead of 2" to 3" diameter ducts, and much less space is taken up. Also less heat loss in areas where the water hose tubing is run, then radiate where copper pipe is.

The water heater in my C Dory25 already had the two pipes for running off a boat's engine circulating water system. This is not a really efficient type of heat transfer. I feel that removing the factory water heater, and putting in one of the small 2.5 to 3.5 Bosch water heaters under the galley--behind the sink, frees up a lot of room, gives almost instant hot water in the galley and shower--vs wasting water until it heats up.

[bobjarrard]

Hard to beat a pot or pan to heat everyday water. On our last sailboat we used large insulated bottles to hold a days worth of water, sometimes we made more hot water at dinner but we tended to eat a big middle of the day meal and snack at dinner time. Showers were always outside the boat cabin and a sun shower with stove heated water or sun heated water worked fine. I have used Red Dots, fine for lukewarm water for most tasks. We also used salt water laced exhaust to wash dishes and to shampoo, not so bad once you get the hang of it. The Refleks stove (https://refleks-olieovne.dk/en/) does a great job of making hot water. Check out this link and others on the Morgan Cloud at https://refleks-olieovne.dk/en/. I built a house that was heated with fan driven registers controlled by high voltage thermostats in each room that were supplied by a PEX pipe system connected to an instantaneous water heater. Beware complexity, it is the mother of disaster. Good luck, sometimes the chase is more fun than the catch. Bob Jarrard

[ChapaRRal Cock]

my tomcat came to me with hydronic heating.
A webasto TSL-17 furnace.
a controller from suremarine called surewire.
An everhot tankless hot water heater
and Sure Marine space heaters. I have 3 in the boat
Honestly, I am still trying to figure all the features out. I do enjoy the dry heat and the hot water though.

[Gene Morris]

Tinbender

We installed a hydronic system in our Tomcat about 6 years ago. The heater is under the sink, expansion tank in head, 1st exchanger is in berth 2nd exchanger is behind refer. The berth exchanger has 3 feeds for defroster 1 for heat in berth 2 for heat at helm. We ran PVC to 2nd exchanger under the bed around the berth, this reduced condensation in berth. The second exchanger vented to feet of 1st officer and another in the compartment under the table vented into the walkway. We are very happy with this set up and makes cruising much more comfortable in the PNW. The defroster feature is great The head is warm and dry and a good place to hang wet clothing to dry quickly.

There are pictures posted in our album under improvements

Good luck
Gene