Heater Installation
This is a narrative on how we installed our diesel fired hydronic heater in our 1997 Caliber 40lrc that we live on in Maine. It is not a substitute for the
installation manual or professional installation. We prefer to do all the work on our boat ourselves. Maybe to save money, but more importantly to better
understand a system, how it works and how to maintain it.
The heater was no different. It really only requires some basic skills that can easily be learned. These skills include basic electrical, mechanical, plumbing and patience. The installation manual is an excellent guide but does not get into the details of how to assemble NPT threaded plumbing fittings, making proper electrical connections or other skills you will need to properly install the heater. This article also assumes the installer has this knowledge. We closed on the boat in late August shortly after selling our house. We would have a few months to get her ready for living aboard full time.
The first consideration was heat. Luckily the Caliber came with a Mermaid reverse cycle AC/heating system that was installed by the previous owner. This unit basically acts like a heat pump drawing heat or cold out of the surrounding water. As long as the water stayed warm enough we would have heat. That would get us through the fall. The Mermaid also requires AC power that we get from either shore power or our onboard 5kw engine driven generator. We do a lot of cruising in the fall and do not like running the engine so the heater would have to run on 12v while on the hook. We also wanted a heater that would continue to run if there should be a power outage at our marina. Maine usually experiences at least one multiday power outage every winter.
After a lot of research we chose the ITR Hurricane H2 heater. This is a 35,000 btu heater which will be more than adequate to heat our home in the cold winters we experience in Maine. From our research, this is considered the best built and most reliable heater available for our application. I also looked at the different components to make sure they would fit nicely in our boat. Some of its many features include the ability to heat water on demand and preheat your engine. While I do plan to install these options, this installation only covers the baseline function of heating the boat. We worked with an ITR dealer and came up with a list of components needed for our installation. I placed the order and all the parts arrived in the next couple of weeks. Once all the components arrived it was time to figure out where to place them. Our plan was to dry fit all the pieces and then go back and do the permanent installation. The exhaust thru hull would have to be installed before the heater, circulation pump and expansion tank but these components need to be considered as the exhaust pipe itself will need to be routed around them.
installation manual or professional installation. We prefer to do all the work on our boat ourselves. Maybe to save money, but more importantly to better
understand a system, how it works and how to maintain it.
The heater was no different. It really only requires some basic skills that can easily be learned. These skills include basic electrical, mechanical, plumbing and patience. The installation manual is an excellent guide but does not get into the details of how to assemble NPT threaded plumbing fittings, making proper electrical connections or other skills you will need to properly install the heater. This article also assumes the installer has this knowledge. We closed on the boat in late August shortly after selling our house. We would have a few months to get her ready for living aboard full time.
The first consideration was heat. Luckily the Caliber came with a Mermaid reverse cycle AC/heating system that was installed by the previous owner. This unit basically acts like a heat pump drawing heat or cold out of the surrounding water. As long as the water stayed warm enough we would have heat. That would get us through the fall. The Mermaid also requires AC power that we get from either shore power or our onboard 5kw engine driven generator. We do a lot of cruising in the fall and do not like running the engine so the heater would have to run on 12v while on the hook. We also wanted a heater that would continue to run if there should be a power outage at our marina. Maine usually experiences at least one multiday power outage every winter.
After a lot of research we chose the ITR Hurricane H2 heater. This is a 35,000 btu heater which will be more than adequate to heat our home in the cold winters we experience in Maine. From our research, this is considered the best built and most reliable heater available for our application. I also looked at the different components to make sure they would fit nicely in our boat. Some of its many features include the ability to heat water on demand and preheat your engine. While I do plan to install these options, this installation only covers the baseline function of heating the boat. We worked with an ITR dealer and came up with a list of components needed for our installation. I placed the order and all the parts arrived in the next couple of weeks. Once all the components arrived it was time to figure out where to place them. Our plan was to dry fit all the pieces and then go back and do the permanent installation. The exhaust thru hull would have to be installed before the heater, circulation pump and expansion tank but these components need to be considered as the exhaust pipe itself will need to be routed around them.
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After spending many hours in the port sail locker I determined the placement of the heater, expansion tank, overflow bottle, control
panel, exhaust thru-hull and circulation pump. I built a platform for the heater using Garolite and a poplar frame base. Two adjacent sides of the frame were attached to existing panels in the sail locker. A block was fabricated to match the hull contour to support the opposite corner. This block was adhered to the hull using an epoxy mush and later taped for additional strength. When positioning your heater, make sure you have access to all the necessary components that will require maintenance. The Hurricane H2 has an end access panel that provides access for service. The other three sides require only a one inch clearance.
panel, exhaust thru-hull and circulation pump. I built a platform for the heater using Garolite and a poplar frame base. Two adjacent sides of the frame were attached to existing panels in the sail locker. A block was fabricated to match the hull contour to support the opposite corner. This block was adhered to the hull using an epoxy mush and later taped for additional strength. When positioning your heater, make sure you have access to all the necessary components that will require maintenance. The Hurricane H2 has an end access panel that provides access for service. The other three sides require only a one inch clearance.
Heater Unit
Control Unit
Circulation pump and expansion tank. I used unions on the inlet and outlet of the heater so the heater could be removed for service in the future without draining all the antifreeze.
Next I needed to determine the location of the fan units. These are small radiators with PC type fans that blow air through them out into the living areas. In order to install the fan units in the cabin I first had to relocate some of the AC components in the salon and aft cabin. I also had to shuffle around some electrical components in the nav station seat. I determined the location of the fan units by figuring out the most efficient and easy run for the heater hose and proper heat disbursement in the cabins.
Fan Unit
All fan units are connected using Gates Duro-Flex 3/4" hose and shutoff valves so they can be replaced without draining the system or making a huge mess.
2 Way adjustable teak grill.
Now that the fan units are installed I could install the thermostats for the three zones. You do not want to install them in direct line of the fan unit output or you will get the fans cycling unnecessarily and cause uneven heating. I used some inexpensive LUX programmable thermostats so we could schedule the room temperatures for different times of the day.
The exhaust thru-hull was the next item to be installed. I purchased a 30° exhaust port to install in the boats reverse transom. After measuring the angle of the transom, it was determined that an adapter needed to be fabricated to allow the thru-hull to slope upwards as it entered the transom. This will prevent water from pooling in the exhaust and causing premature failure from corrosion.
Exhaust Thru-hull.
A local machine shop fabricated the shim out of 316 SS from my design. The cost was appr. $150.
Exhaust through-hull.
The placement of the thru-hull must allow for the exhaust pipe to have a loop to prevent following seas from flooding the heater. I mounted the thru-hull low enough that there would be room in the sail locker to create a loop from the flexible exhaust piping.
Next, I determined the location of the remainder of components and dry fit them. Now that I was happy with the placement I removed the components to allow for the installation of the exhaust pipe and fiberglass exhaust insulating tape. I cut the pipe to length and applied the wrap up past the expansion tank location so I would be finished working behind that area and could reinstall the tank and pump. I then reinstalled the heater and permanently mounted it, attached the exhaust piping and finished wrapping the pipe.
I also installed a fuel transfer pump and filter to allow me to move and polish fuel from one tank to the other. This setup allows me to run the heater on one tank and the engine on the other and have the full 210 gallon capacity for either.
The wiring of the heater is very straightforward. The thermostats are fed with 12v and when triggered feed 12v to the control module which in turn supplies current to the fan unit. The negative side of the fan is dependent on an aquastat on the fan unit so it does not ground until the glycol mixture is up to temperature.
The last step was to fill the heater. We used a hand pump to fill the system with a 50/50 dilution of propylene antifreeze. The return hose was fed into the bucket we were drawing out of so we could eliminate as much air as possible. Next, I started up the circulation pump to ensure there were no leaks in the system. At this point I went over the final check-list and then fired up the furnace. It took a few attempts to get the fuel pump to fill the lines. Once the heater ignited I went through the boat and tested all the zones and fan units. Everything worked properly. We now have a very warm boat and can use it at anchor. The first week we had some moderately cold nights and days. Lows in the 20s and highs in the thirtys. The heater ran for 51 hours and consumed 16 gallons of fuel. We do have a clear shrinkwrap cover that allows the deck to heat up fairly well during sunny days so that helps keep the fuel usage down a little during the day.
After running the heater for a few weeks, we decided that the fans were a little loud. So I installed a PWM(pulse width modulator) that allows infinite control of the fan speed. We can now fine tune the heat and noise output.
This is the PWM that I had to mount in custom boxes.