Once the pre-installation preparations for the new heat system were complete, it was time to get to work with the actual installation. At a glance, there are a lot of components that go into creating and distributing heat throughout the boat. To avoid becoming overwhelmed I split the project into five parts: plumbing, ducting, electrical, exhaust, and fuel delivery. By focusing on one piece of the puzzle at a time I was able to keep a clear mind and slowly tick off tasks from the long to-do list.
After maneuvering the boiler into place with the assistance of a few friends and some clever rigging, the plumbing work began. We decided to divide the boat into four zones to maintain control of heat distribution. The four zones are:
- Forward cabin and head
- Main salon and galley
- Engine room
- Aft cabin and head
The zones are split at a supply manifold, allowing us to close individual zones for maintenance, or for warmer climates when we want to use the boiler to heat domestic water without heating the boat. After departing the manifold a supply line provides each zone with hot water. Each zone then contains one or more radiators which convert the hot water to warm air before returning back to the manifold in the engine room.
The most difficult aspect of the plumbing install was physically running the piping throughout the boat. With a little planning, a lot of hanging upside down in the bilge, and some tight squeezes, I pieced together each zone loop using as few connections as possible. Pex fittings are made with a large crimping tool creating simple and secure connections. However, the tool is quite large and difficult to use in tight spaces.
I learned, the hard way, that if the system wasn’t put together in exactly the right order, I wasn’t able to crimp the fittings. Trial and error eventually paid off and I was able to complete the plumbing in approximately 4 days, about a day per zone.
Aspects of the ducting were completed during the plumbing phase as I had to connect the radiators as I went. The radiators are essentially small heat exchangers with a 12V fan blowing air across the hot water loops. This air is then channeled through ducting to an outlet located at a site of your choosing. This allows the radiator to be mounted out of sight, leaving only a small round vent visible. The size and length of the ducting varies with the size of the radiator but you can order more if you have a longer run.
In the forward cabin (as well as the aft cabin) a single radiator is used to heat the cabin as well as the adjacent head. For this, we used a radiator with multiple ducting outlets to divert the heat where needed. The radiators were located in cabinets along with an adjoining bulkhead so that ducting could easily reach both spaces. Routing the ducting was fairly straight forward as it was much shorter runs than the plumbing. The only difficult part was securing the hose clamps onto the radiators in tight places. For the main salon we decided on a brass flush mount radiator which is mounted under the starboard settee, so no ducting was necessary. There was already a vent from the old heating system there so this also worked as a good way to fill in the old hole. The brass finish looks really nice against the dark wood.
Each radiator has two 12V fans to push air across the coils, requiring power from the control board. I ran wiring throughout the boat, mostly in similar routes as the plumbing, to power the fans and to each of the four thermostats. With so many wires coming into the engine room from all directions, labeling became very important.
Sure Marine Services makes it much easier to complete the wiring of the system with the included SureWire Kit. This control board brings all wiring into one place and takes out the guess work of all critical connections. The manuals included were sufficient to correctly complete the wiring, but anytime I had a question SMS techs were happy to assist. The boards are an important interface using 12V power to interpret thermostat signals, power fans and control the 110V boiler panel.
The most nerve-wracking moment of the process was when we drilled a 4” hole in the hull for the exhaust to pass through. A double wall thru-hull fitting isolates the fiberglass from exhaust temperatures and uses a gasket to seal the exterior flange against the hull. The process went fairly smooth but it is never a good feeling to put a large hole in your boat.
One challenge with the exhaust is that it must be of solid pipe, and flow continuously uphill to the outlet, meaning that due to our boiler location we could only manage a very short run. We were concerned about water ingress while sailing and planned to use a water trap to mitigate any splashing water, but unfortunately, there was just no way to fit it in the space. Had we used the water box the outlet would have been almost a foot lower on our hull, and we felt that it would be safer to forgo the box and move the exhaust outlet as high as possible. We will use a large rubber expanding plug to protect from water intrusion while sailing. The exhaust pipe is 2-3/4” stainless steel connected with exhaust cement and clamps and wrapped with insulation.
The final process, before commissioning, was the fuel supply. I drilled a hole in the top of the fuel tank, using a shop vac to contain as much dust as possible, and installed the fuel pickup. This is a bit of a balancing act as you use a small piece of bent wire to lower the backing nut into the tank while careful threading the pickup into place. Thankfully I didn’t drop anything into the fuel tank. The run from the fuel tank to the heater is difficult and had to weave through the bilges requiring some innovative thinking and some awkward positions. A few frustrating hours later I had completed the run and installed the inline fuel filter.
With all systems appearing ready, I called a good friend to help me fire it up for the first time. I thought it might be good to have a hand, particularly for bleeding the fuel system, which I anticipated possible problems with. We tried over and over to bleed the system but just could not get a consistent flow of fuel to the filter, which is mounted just before the furnace.
Eventually, we decided it was time to regroup and we went over the fuel supply from start to finish. Once we removed the fuel pickup and return we realized I had reversed the connections which meant that the pump was trying to draw fuel from the return. Since the return empties near the top of the tank, it was above the level of fuel and obviously not drawing fuel. Oops! Feeling a little silly I put the system back together, correctly this time, and we tried priming the system again. Bingo! That did the trick.
Now that the fuel was present at the burner, the system should fire right up. Time after time the pump would operate, the burner would try to start, but nothing would happen. I got on the phone with SMS and we went through a series of tests, confirming the accuracy of my wiring connections and the presence of fuel. Suddenly, the tech assisting me said, “Any chance there is a red light on the front of the burner?” Sure enough, there was. I pushed the button and the system immediately came to life! What a relief! The system just needed to be reset after the numerous attempts to bleed the fuel. Within moments the heat was radiating through the boat.
An immense sense of relief washed over me as the system continued to produce heat while I cleaned up the cabin from the day’s work. This project was expensive, time consuming, and the pressure of an approaching Maine winter added to the stress of the install. Yet despite those challenges I truly enjoyed the installation process and am proud of the work I accomplished. Now that the installation is complete and we have a winter of hard testing behind us, look for the upcoming review of the system’s performance.