Diesel Heater Installation: What's Included, What You Need, and When to Hire a Professional
Share
A diesel heater installation isn't complicated, but it is unforgiving. Five systems have to be right — mounting, exhaust, combustion air, fuel and electrical — and the ones people rush are the ones that cause problems later: exhaust routing and fuel line setup.
This guide covers what comes in the box, what you'll need to buy separately, the specifications that actually matter, and the point at which hiring a professional is the better decision.
Time required: half a day to a full day for a first install. An experienced installer will do it in two to four hours.
What's in a Diesel Heater Installation Kit
A complete GC kit covers the heater and the systems that connect it. BISON air heater kits include:
- The heater unit
- A pre-assembled wiring harness
- Fuel lines and the fuel pump
- A fuel pick-up tube
- Air ducting
- A mounting plate and hardware
- Exhaust and combustion air pipes
- The controller
WALRUS coolant heater kits include the same core items, plus a coolant pump and an exhaust pipe with muffler.
The kit is built around the heater, not around your vehicle. Everything specific to where it's going — how it mounts in your floor, how the exhaust exits your hull, where the fuel comes from — is the part you have to work out.
What You'll Need That Isn't in the Box
| Item | Why |
|---|---|
| Carbon monoxide alarm | Non-negotiable in any sleeping space. A correctly installed diesel heater keeps exhaust outside, but exhaust leaks happen and this is what catches them |
| Auxiliary fuel tank (optional) | If you'd rather not tap the vehicle tank |
| Hole saw and step drill | For the floor penetration and exhaust exit |
| Sealant suited to the surface | Automotive seam sealer, or a marine-grade sealant on a boat |
| Extra cable and fuse | If the supplied harness doesn't reach your battery, in the correct gauge |
| Marine thru-hull fitting | For boats, instead of a plain exhaust exit — GC stocks these |
| Exhaust heat shielding | Anywhere the exhaust runs near something that can be damaged or touched |
| Multimeter | For checking voltage at the heater, which is the first thing to verify if it won't start |
The Five Systems You're Installing
1. Mounting
Mount the heater on a flat surface. An uneven surface twists the case and stops it sealing properly. If the surface is thinner than 1.5 mm, use a mounting plate. M6 bolts torque to about 6 Nm.
Keep the fan clear of anything it could rub against, keep the unit away from flammable material and water spray, and leave the label visible. Mind the tilt limit for your model — the manual shows the permitted range.
Where it goes: under a bench seat, in a gear locker, under the bunk, or in an engine bay, as long as the intake and exhaust can get outside and the hot air outlet can reach the space you're heating.
2. Exhaust
The exhaust carries combustion gases outside, and it's the system that most affects safety. Rules from the manual:
- Use only the supplied pipe — corrugated stainless steel
- Minimum bend radius 50 mm, and all bends together no more than 270°
- Exit pointing down at 90° ±10°, facing away from the direction of travel
- Shield any exposed section so nobody can touch it and nothing nearby is damaged
- Exhaust must not be able to re-enter the vehicle, including through a vent, window or the heater's own intake
3. Combustion Air Intake
The intake feeds the sealed combustion chamber. It draws from outside, which is what keeps the air inside your van or cabin clean.
Route it downward, out of the direction of travel, away from road spray and dirt. The same 50 mm bend radius and 270° total bend limit apply. Keep the end cap on, and keep it well away from the exhaust outlet so the heater never breathes its own exhaust — that causes overheating faults and poor combustion.
4. Fuel
The fuel system is the most common source of startup problems.
- Fuel pump angle: mount with the outlet tilted upward 15–35°. Flat or downward-facing pumps trap air
- Standpipe depth: the pick-up should sit 30–40 mm above the bottom of the tank, so it doesn't draw sediment or water
- Replace the fuel filter, line and clamps every two years or when dirty
Air in the fuel line is the number one cause of startup failures. Prime the line properly and check every connection for leaks before the first run.
5. Electrical
- Battery leads: 2.5 mm² cable
- Main fuse: 20 A on a 12 V system, 15 A on 24 V
- Secure the harness at intervals of no more than 300 mm, and protect any wiring that runs outside the vehicle
- Before any welding on the vehicle, disconnect the positive supply
Run the heater from a battery that can handle the glow-plug load. Startup pulls 13–25 A for 30 to 60 seconds, and low voltage during that window is the most common cause of fault codes on a new install. Size your cable and fuse for that surge, not for the heater's running draw.
Exhaust Installation: The Part People Get Wrong
If an install fails early, the exhaust is usually why. Four mistakes account for most of it:
- Too many bends. Every bend adds back pressure. Stay within the 270° total and the 50 mm minimum radius.
- The exhaust exits too close to the air intake. The heater ends up breathing its own exhaust, which causes overheat codes and sooty combustion. Separate them, and put the intake upstream of the exhaust.
- An exhaust tip that lets water in. Pointing down at 90° ±10° isn't a style choice. An upward-facing or horizontal tip collects rain and road spray, which corrodes the heat exchanger from the inside.
- No heat shielding. The exhaust gets hot enough to melt plastic, scorch wood and burn skin. Shield any run near anything vulnerable.
On a boat, add a proper marine thru-hull fitting and a muffler. Exhaust temperature, wave wash and a sealed cabin make marine installs the least forgiving of the lot.
Installation by Vehicle Type
Van diesel heater installation
Usually the simplest: the heater goes under a bench or bed platform, with pipes dropping through the floor. The main decisions are tapping the van's fuel tank versus fitting an auxiliary tank, and where the ducting puts warm air. A 2 kW unit heats most conversions, and oversizing causes short cycling.
RV diesel heater installation
More space to work with, more ducting to plan. The questions are whether you're heating one zone or several, and whether the heater lives in an exterior bay or an interior locker. Exterior bays make the pipe routing easier but need protection from spray.
Marine diesel heater installation
The most demanding, and the one most worth paying for. Installs need marine-grade thru-hull fittings, a muffler, careful attention to where the exhaust exits relative to hatches and ports, and planning for a vessel that heels and takes water over the deck. Our marine heating guide covers the system choices.
Truck and equipment installation
Bunk heaters mount in the side locker or under the bunk, with fuel drawn from the main tank. For engine pre-heat, a WALRUS coolant heater plumbs into the cooling system instead, which is a different job from an air heater install.
What Installation Costs
DIY: the price of the kit, plus roughly $50 to $150 of extras — sealant, fittings, cable, a CO alarm — and most of a day.
Professional: typically a few hundred dollars in labour, usually three to five hours of shop time, more for a marine install where thru-hull work and cabinetry are involved. Rates vary by region, so get a quote from a local dealer.
Worth factoring in: a professional install gives you someone to call if something isn't right, and a documented install if you ever make a warranty claim. Check the warranty terms for your intended use before you start, since coverage differs between highway, recreational, marine and off-highway use. Our warranty page has the details, and damage caused by improper installation isn't covered under any of them.
When to Hire a Professional
Do it yourself if you're comfortable drilling through your vehicle, working with 12 V wiring, and following a manual exactly.
Hire a professional if:
- It's a boat. Marine exhaust routing and thru-hull work have the least margin for error, and the consequences of getting exhaust into a sealed cabin at anchor are severe
- You'd be tapping a fuel tank you're not confident working on, particularly a modern vehicle with a sender unit you don't want to damage
- The vehicle is leased, under warranty, or a work truck where an unapproved modification could cause problems
- You're fitting a fleet. Consistency matters more than the labour saving
- You're installing a coolant heater. Plumbing into a cooling system, bleeding air out of it, and getting the circulation right is a bigger job than an air heater install
- You don't have a full day and the forecast says the cold is coming
Our authorized dealers across Canada and the US do these installs regularly.
Mistakes That Cause Early Failures
- Oversizing the heater. Too much output for the space means short cycles, carbon build-up and early part failure. Match the heater to the heat load
- Skipping the fuel line prime. Air in the line means a startup failure on the first cold night
- Undersized or corroded power cable. Voltage drop during the glow-plug cycle causes faults that look like a broken heater
- Mounting the fuel pump flat. It needs the upward tilt to purge air
- Routing the exhaust where it can be touched. It gets hot enough to burn
- Running only short cycles on the lowest setting. Carbon builds up fast. Give the heater a long, hot run regularly — see the maintenance checklist
After Installation: The First Run
- Check every fuel connection for leaks before powering up
- Measure voltage at the heater, not at the battery
- Run it outside or with the area well ventilated the first time. New heaters smoke a little as manufacturing oils burn off
- Let it complete a full cycle, including the cool-down. Never cut power mid-run
- Check the exhaust by hand along its length — carefully — for leaks at the joints
- If you get a fault code, our error code guide lists what each one means
Every model's manual is on our installation guides page. Read the one for your heater before you start, not after something doesn't work.
Frequently Asked Questions
How long does a diesel heater installation take?
Half a day to a full day for a first-time install, and two to four hours for an experienced installer. Marine installs take longer because of thru-hull fittings and access.
Can I install a diesel heater myself?
Yes, if you're comfortable drilling through your vehicle, working with 12 V wiring, and following the manual's specifications for exhaust, intake and fuel routing. The work isn't difficult, but exhaust routing and fuel line setup have to be right. Boats and coolant heater installs are better left to a professional.
What comes in a diesel heater installation kit?
A GC kit includes the heater, wiring harness, fuel pump, fuel lines and pick-up tube, air ducting, exhaust and combustion air pipes, mounting plate, controller and hardware. You'll usually need to add a carbon monoxide alarm, sealant, and a marine thru-hull fitting on a boat.
Where should the exhaust exit?
Pointing down at 90° (±10°), away from the direction of travel, and positioned so exhaust can't re-enter through a vent, window, hatch, or the heater's own combustion air intake. Keep all the bends within 270° total with a minimum bend radius of 50 mm.
How much current does a diesel heater draw at startup?
13 to 25 amps for the first 30 to 60 seconds, while the glow plug heats. Running draw is far lower. Size the cable and fuse for the startup surge, because voltage drop during that window is what causes most faults on a new install.
Do I need a carbon monoxide alarm with a diesel heater?
Yes, in any space where people sleep. A correctly installed diesel heater keeps all combustion gases outside the living space, but an exhaust leak or a badly placed outlet can change that, and an alarm is what tells you.
Can I install a diesel heater on a boat myself?
It's possible, but it's the install we most often recommend handing to a professional. Marine installs need proper thru-hull fittings, a muffler, and exhaust routing that accounts for heeling and water over the deck, in a cabin that's sealed when you're sleeping in it.
What size diesel heater do I need?
A 2 kW unit suits most van conversions, with 4–5 kW for larger RVs, boat cabins and sleeper cabs. Bigger isn't better: an oversized heater short cycles, which builds carbon and shortens its life.
Planning an Installation?
Tell us the vehicle and what you're heating, and we'll help you pick the right heater and work out the install. Call 1-800-517-7740 (Mon–Fri, 9 AM–5 PM PT) or email info@generalcomponents.ca.
Shop Heater Kits · Installation Manuals · Find an Installer · Parts & Accessories
Specifications quoted are from GC installation manuals. Always follow the manual for your specific model and voltage.
