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How To: Installing A Boat Heater

As much as we wish every day on the water was like the photo above, we all know not every day is sunny and 90 degrees. Any avid boater spends time on the water when it is colder than our ideal conditions. The serious water sports enthusiasts start those summer mornings bright and early when it can be chilly and keep riding even once the temperatures quickly drop due to the sun setting. Many boaters start their riding season well before summer starts and keep riding well into fall and winter until it becomes time to winterize the boat until next Summer.

If this sounds like you at all, a heater system in your boat is an absolute must and a total game changer. Keep you and your passengers toasty warm during those colder days spent out on the water. In this WakeMAKERS How-To Guide we will go over everything you need to know about marine heater systems. From how they work to choosing one for your boat and installing it, you will be a boat heater expert once you are finished with this quick read. Enjoy!

How Does a Boat Heater Work?

Very similar to your vehicle's heater, a marine heater system works by using hot water from the boat's engine, running it through the heater core where a fan distributes the warm air to outlet vents throughout the boat.

Choosing a Boat Heater System

WakeMAKERS is proud to be a Heater Craft dealer, the world leader in marine heating systems. From complete system kits to individual parts, WakeMAKERS has everything you need to keep your riders warm inside the boat.

Seen above is one of the Heater Craft Complete Marine Heater Kits. Making it easy for you to customize your heater system, this complete kit can be configured with the desired number of outlets and a circulation pump upgrade.

Choosing Number of Outlets

Heater Craft 200 and 300 Series Boat Heaters

The first step in configuring your boat's new heater system is determining the number of outlets that it will have and what type of vents to attach. WakeMAKERS offers Heater Craft's 200 and 300 series heating units in our complete marine heater kit. The 200 series unit has two outlets and the 300 series unit has three outlets (seen above).

Each of those outlets can be configured to have either a louver vent or hot tube based on personal preference.

Pictured above (L to R) is the hot tube and euro louver, the two vent options for configuring your boat heater.

Low Speed Circulation Pump Upgrade

Since the heater unit is typically mounted in a location not close to the boat's engine, often times there won't be enough water circulation in the system while idling or at low RPMs, causing the heater to not output warm air at its full output. The circulation pump helps move hot water from the engine to the heater's coil core to help output warm air through all the vents.

The circulation pump upgrade is a very nice add-on for those who like to use the heater while getting ready or finishing up a riding set, not only when the boat is in motion and at high RPMs.

The Fun Part:

How to Install a Boat Heater

boat heater installation

You've figured out which heater kit you are going with so now it is time to go over the installation process. With the correct tools, a modest level of savviness with tools, and a good portion of an afternoon this can be a fairly straightforward DIY project. Of course you can always take your boat to your preferred local marine service center for a professional installation of your new heater. First we'll go over the required tools for a self installation.

Needed Tools:

  • -Phillips screwdriver
  • -Power drill and bits
  • -1 inch hole saw
  • -3 inch hole saw
  • -4 inch hole saw
  • -Wrench set
  • -Hose cutter
  • -Wire cutter
  • -Wire stripper
  • -Crimping tool
  • -Plumber's tape

Step One: Installing Heater Unit

Before getting started on installing the heater unit in your boat, you will want to determine where it will be mounted. The most common spots in an inboard boat is in the observer's compartment (under passenger seats) or underneath the dash.

Using the adjustable mounting brackets and screws provided in the kit, you will secure the heating unit with the hoses facing the stern (back) of the boat and the duct fittings facing the bow (front) of the boat.

Step Two: Plumbing The Heater

Now that the heating unit is fastened in the boat, the next step is to plumb it to the boat's engine so that it has a source of hot water. Both the 200 and 300 series heating units will two heater hoses, one that takes hot water from the engine to the heater core while the other hose will be used as a return line.

Using the provided heater hose in the kit, run two lengths of the heater hose from the engine compartment to where you mounted the heating unit. Quick Tip: use a fish tape to pull the hose from the engine compartment to the mounted unit. Once you've snaked the fish tape all the way through, tape the heater hose to the end while pulling the fish tape out and feeding in the heater hose. It is very important to make sure the heater lines are not kinked or interfering with the engine such as its fan belt. It is recommended that you use cable ties to secure each of the hoses along their entire run. This will ensure the lines don't get kinked up and prevent them from chafing and slowly wearing down which can cause eventual leaks in the line.

Step Three: Route and Connect Hoses

Next you will connect the two heater hose lines to the heating unit. Water can flow in either direction so don't worry about which port you connect the intake and return line to. Connect the supply line to the engine at the intake manifold. Remove the NPT plug on top of the manifold (near the thermostat housing) and attach the hose using one of the provided brass fittings and a stainless steel hose clamp. It is recommended that you use plumber's tape on all of the fittings to ensure a watertight connection that doesn't leak. Next you'll want to plumb the return line. We recommend plumbing the return heater line lower on the engine using a NPT brass fitting, a hose clamp, and plumber's tape for a watertight seal.

Some people prefer to install shut off valves for each heater line for a quick, easy shutoff if the system starts leaking.

Step Four: Install the Vents

Determine where you want the vents to be located in the boats. Depending on the type of vent you are installing, you will need to use a different size hole saw.

Hot Tubes: use a four-inch hole saw

Louver Vent: use a four-inch hole saw

WARNING: before installing the vents in desired location, check behind the mounting surface for sufficient depth and any interference.

Once you've deemed the desired vent location is good to go, it is time to start cutting the hole using the correct size hole saw. For the cleanest, most professional looking cut you should start the cut from one side and keep going until the pilot bit appears on the other side. At this point, stop and finish cutting the hole from the opposite side. The vents will snap into place once the holes are cut.

Now that the vents are in place, it is time to route the ducts from the heater unit to each vents. Pull the vent hose so that it reaches each end, cut it to that length, and then secure using the plastic cable ties.

Step Five: Wire and Mount Electrical Switches

The complete heater kit comes standard with one high/low switch and indicator assembly. This switch will control the fan inside the heater and its speed. Install this switch near the helm where the captain can easily reach it. Next step is to power the fan motor. Make sure the wires are correctly fused and that the wires are supported throughout their whole length.

The rocker switch that is provided in the kit mounts in a standard rocker switch cutout. You can either add a new switch panel or add it to your existing switch panel, replacing a switch that you don't frequently use. To give it that total OEM look, some get a factory switch so that it matches the rest of the switches on the dash.

Once the switch is mounted and all wires are correctly routed, you've completed the install. Congrats!

Now it is time to get out on the water to test out your boat's new heater system and start staying warm out there.

Got Questions? We're Here to Help!

We hope you found this resource piece useful and learned a few things along the way. If you still have questions, our friendly team of product experts are available via phone or email to help get your boat's heater system dialed in. Whether you are having difficulties deciding which heater kit to purchase or needing advice on your DIY install, we are here for you every step of the way.

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