22 Diesel Heater Installation Notes

In this blog post, you’ll read: When you understand these 22 heater installation precautions, your heater will work for 8-10 years.

Table of Contents

22 Diesel Heater Installation Notes

In previous years only a few professional technicians and service stores installed and serviced diesel heaters. But, as the popularity of diesel heaters kept rising, many new manufacturers emerged on the market. Now, even smaller stores and diesel heater users can install and service them.

Many small motorhome manufacturers or wholesalers of RV, truck, and boat parts are also interested in selling diesel heaters, as they are perfect for such vehicles. But, because these companies are new in the diesel heater market, they usually lack the technicians with the right knowledge who fully understand how diesel heaters work.

Those companies are faced with various potential problems that can occur after the heater is installed incorrectly. As a result, customers start complaining.

But, installing a diesel heater properly is not that complicated. Even a regular auto mechanic with decent experience can do it right, and the heater will work well. That’s why we created this article – it will give you a detailed understanding of diesel heaters and will make the installation process a breeze.

Truck with Warmda heaters

After surveying most of the best selling diesel heaters on the market, the engineers at Warmda LLC and I have created this list of 22 heater installation tips. Those are certainly going to help you to solve common issues customers face during the installation. Let’s get started!

1. Choosing The Mounting Location For The Diesel Heater Host

Typically, diesel heaters are mounted in fixed positions on RVs and trucks. You just need to have the heater mounted upright, and it will work well.

Upright mounted diesel heater

However, if you are selling boat parts or have a boat repair company, you will need to install diesel heaters for your customers, but rotated 90 degrees. If that is the case, you need to pay special attention to the fact that the fuel intel should be facing upwards when the heater is rotated. That will allow the fuel to burn in the combustion chamber completely.

The fuel inlet is upward, the correct installation method on the boat

You need to make sure that the heater oil inlet isn’t facing down. There is a danger that the diesel fuel will flow out of the heater onto the floor, creating a fire hazard.

The fuel inlet is facing down, wrong installation method
The fuel inlet is facing down, wrong installation method

Another option is to use an L-shaped stainless steel mounting plate, which will allow you to mount the heater upright, even when installing it on a boat.

Warmda L-shaped stainless steel mounting plate
Warmda L-shaped stainless steel mounting plate

2. Things To Keep In Mind When Fixing The Heater Host

The heater is made of a plastic or aluminum housing and a heater core, and after installing it, you will need to turn the heater impeller.

After installation, turn the impeller by hand
After installation, turn the impeller by hand

However, you might find that the impeller is sticking. If that is the case, you have allowed the heater housing to dislodge while securing the heater, which caused the housing to catch on the motor impeller.

But, that’s a quick fix, and all you need to do is loosen the four screws on the bottom of the heater. Then, adjust the position of the housing and tighten the screws – problem solved.

3. Heater Cable Installation Notes

At first glance, the cable seems to be one of the most insignificant parts of the heater. You might think that all you need to do for it to work properly is to connect it. But, that is a major misconception.

Warmda Heater Cable

If you don’t pay close attention when installing the cable and wires, the heater may interfere with other electromagnetic waves produced by other electrical equipment working nearby, causing malfunctions. The heater might also leak electromagnetic radiation, which can cause other equipment in its proximity to have issues.

Pay Attention To These Details

First, make sure that the heater power cord is correctly connected to the battery’s positive and negative terminals.

Also, the heater’s power cord needs to have an appropriate length. Some manufacturers try to reduce heater costs and send very short zero wire for the power cord, resulting in you not being able to connect the zero wire to the battery.

The length of the power cord must be the same
The length of the power cord must be the same

The problem is that you can’t use a different wire to extend the zero wire for it to reach the power supply, as a direct connection of the two wires may cause interference with the heater.

The only solution is to replace the entire wire. Never try to separate zero or the fire wire of the heater. If you do, the heater will show various errors caused by electromagnetic interference, and you won’t be able to use it properly.

 4. Heater Cable Too Long

Contrary to the point from above, some manufacturers will provide very long cords. However, that can prove to be problematic too, as sometimes the distance between the heater and the control panel/batter is short.

Excess cables are coiled and fixed in place
Excess cables are coiled and fixed in place

So, after you finish installing the heater, you may realize how the power cord leftover is too long and that you need to coil it up and secure it in place. This is the only right thing you should do if the cable is too long – anything else might result in electromagnetic wave interference.

5. Heater Power Cord Connection Notes

On most heaters (and other devices in general), the positive wire in the power cord is colored red, while the negative wire is colored black.

Naturally, you need to connect the red cable to the battery’s positive terminal and the black one to the negative terminal.

This is obvious, but if you don’t do it this way, not only that the heater won’t work properly, but it can be severely damaged, and a short circuit can even burin the main control panel. Therefore,

Pay attention!

6. Where To Mount The Control Panel

Diesel heaters on the market usually have two types of control panels, one with a temperature sensor and one without it. The design with the sensor makes it easier to detect the temperature inside the compartment. The other heater type has a temperature controller located at the heater’s cooling fan’s air intake, not inside the control panel.

When installing a control panel with a built-in temperature sensor, you need to pay attention to the control panel’s location and height. We recommend you to make sure that the heater’s air outlet is not directly facing the control panel. If you install the control panel in front of the air outlet, it is likely to trigger the temperature sensor, and the heater will stop working before the air inside the cabin is at the desired temperature.

Installation location of the control panel
Installation location of the control panel

It is also a good idea not to mount the heater’s control panel too high. As you know, hot air is lighter than cold air, and if you install the control panel too high, near the roof/ceiling, the air around it will be the first to heat up, and the sensor inside the control panel will turn on the heater prematurely.

But, for the same reason, the control panel should not be placed too low either. Doing that will cause the cold, heavier air to collect around the sensor, which will cause it to run too long. That will not only raise the temperature inside the cabin too much but will also consume more fuel.

The ideal location for the control panel is halfway up the height of the cabin. If you install it at this height, the heater will operate perfectly.

7. Tips When Using The Heater For The First Time

After you finish the heater installation, let the fuel pump work before turning the heater on.

If you start the heater directly, there may be air present in the fuel delivery system. This might cause the heater to start improperly, and it will display an error code.

Unplug the tubing
Unplug the tubing

To prevent this, once you finish installing the heater, unplug the fuel line from the heater inlet, and start the heater in “auto pump mode.”

That will allow the fuel pump to start working and remove the excess air inside.

Once you see the fuel coming out of the fuel line you unplugged, connect it back to the heater inlet. After that, you can start the heater, and it will work normally

8. Tips For Choosing Adqequate Heater Cooling Air Inlet Location

One common mistake when installing the tube of the heater’s cooling air intake systems is that people set it up so that it draws the air from the outside and blows it into the compartment’s interior.

The air should actually blow from the inside to the outside, not the other way around.

The distance between the heater air inlet and the wall is not less than 20 cm / 8 inches
The distance between the heater air inlet and the wall is not less than 20 cm / 8 inches

The diesel heater is warming the air inside the compartment and allows it to circulate. But, because the heater is blowing the air out, make sure it is at least 20 cm / 8 inches away from a wall.

9. Diesel Heater Fuel Pump Inlet Installation Tips

When it comes to fuel pump inlet installation, a common mistake is turning it the wrong way. If the fuel pump with the oil inlet is facing down, it will not work evenly, as it’s supposed to.

Wrong fuel pump installation position
Wrong fuel pump installation position

When turned downwards, the fuel pump won’t discharge the oil at an even frequency, which will create noise. Also, turning the inlet the wrong way will cause the heater combustion chamber to accumulate carbon.

Correct fuel pump installation position
Correct fuel pump installation position

Furthermore, if the pump outlet is facing down, fuel will flow out naturally if the check valve fails, even if the pump is stopped, which is a hazard.

Correct fuel pump installation position
Correct fuel pump installation position

Therefore, mount the pump so that the discharge port is facing slightly upwards, or put it in an upright position. That way, the fuel coming out of the pump will have sufficient pressure, allowing it to atomize efficiently.

Correct fuel pump installation position
Correct fuel pump installation position

But, if you don’t have enough room for the fuel pump to be mounted tilted, mounting it horizontally can work too.

10. Proper Distance Between The Fuel Pump And The Main Engine

We recommend that the distance between the fuel pump and the central unit should be 60-100 cm (1.87 ft – 3.28 ft).

The distance between the fuel pump and the heater host
The distance between the fuel pump and the heater host

If the distance is too short, the fuel’s pressure coming out of the pump will be too high, resulting in an uneven combustion sound. Also, there may be too much fuel coming out of the fuel pump for it to be fully burned, resulting in carbon buildup. Furthermore, the excess fuel which wasn’t entirely burned may flow out of the heater through the exhaust port.

However, problems will occur if the fuel pump is too far away from the main heater too. If the distance is more than 1 meter (3.28 feet(, the fuel pressure will be insufficient. This will again result in uneven combustion, and the heating output will not be as desired.

11. Fuel Filter Installation Considerations

A fuel filter’s primary function is to prevent contaminants in the diesel fuel from clogging the fuel pump and causing the heater not to work correctly.

Location of fuel filter, fuel pump and main engine
Location of fuel filter, fuel pump and main engine

The problem is that some vehicle maintenance companies are not familiar with diesel heaters. They have employees that don’t know how to fit the fuel filter properly, which causes issues.

Fuel outlet and inlet of the fuel filter
Fuel outlet and inlet of the fuel filter

The fuel filter needs to be installed at the fuel pump’s inlet, as it is the only position that will let it effectively filter the fuel and prevent contaminants from clogging the pump. When installing the diesel filter, pay attention to the direction of fuel flow, as the filter outlet should be connected to the inlet of the fuel pump.

12. Choosing The Heater Exhaust Pipe

When choosing the heater exhaust pipe, you should take one criteria in special consideration – noise. For the best sound deadening, you should use a flexible spiral exhaust pipe.

Warmda flexible exhaust pipe
Warmda flexible exhaust pipe

When the heater works, diesel fuel is combusted in the combustion chamber by mixing diesel vapor and air, ignited by the electric plug. The combustion air enters the combustion chamber in the form of spiral airflow, allowing the chamber’s diesel vapor to mix well with the combustion air. But, when the spiral airflow enters the combustion chamber at high speeds, there will be a lot of noise. That’s the main reason why some diesel heaters are noisy.

Ordinary diesel heater exhaust pipe
Ordinary diesel heater exhaust pipe

As the diesel vapor burns inside the chamber, the noise will also follow it and exit through the combustion exhaust with the fumes, and discharged from the combustion chamber through the combustion exhaust vent.

Comparison of Warmda flexible exhaust pipe and ordinary exhaust pipe
Comparison of Warmda flexible exhaust pipe and ordinary exhaust pipe

But, if the heater has a spiral exhaust pipe, once sound waves encounter the spiral structure, the pipe will cancel most of the sound wave transmission, considerably reducing the noise output. That is the main reason why you should consider picking a spiral exhaust pipe.

 13. Exhaust Port Selection Tips

To secure the exhaust pipe to the heater exhaust port securely, you need to have a spiral exhaust pipe connection. The combustion exhaust pipe is attached to the heater’s combustion exhaust outlet. The outlet is made of aluminum, while the exhaust pipe is made of stainless steel. It relies on an exhaust pipe clip to secure it to the exhaust port.o

Spiral interface of Warmda exhaust pipe
Spiral interface of Warmda exhaust pipe

However, customers often have problems as exhaust pipes sometimes come off the top of the heater while the vehicle is running. That is because many heater manufacturers use unthreaded ports. Those don’t have enough friction to keep the exhaust firmly in place in the exhaust port.

Smooth interface of ordinary exhaust pipe
Smooth interface of ordinary exhaust pipe

That’s why we recommend that all heater manufacturers and sales stores, and customers should use an exhaust pipe with a spiral connection. Only this type of connection will allow the exhaust pipe to hold the heater exhaust system in place securely.

14. Selecting Exhaust Pipe Material And Construction

The combustion system of a diesel heater is entirely separate.

The combustion exhaust pipe is mounted on the vehicle’s underside and is exposed to various corrosive substances at all times and to changing weather conditions. This is why the exhaust pipe needs to have good corrosion resistance. For that reason, most exhaust pipes are made of 304 stainless steel.

Structure of warmda exhaust pipe
Structure of warmda exhaust pipe

Furthermore, the constricted space available at the bottom of the heater requires the exhaust pipe to have good bending properties. A spiral exhaust pipe is made of multiple layers of stainless steel sheets that are overlapped and extruded. That allows good maneuverability and saves installation time.

15. Exhaust Port And Spiral Exhaust Pipe Orientation

When installing the heater exhaust pipe you should pay special attention to the orientation of the exhaust port. Don’t install the pipe horizontally or with the exhaust port facing upwards.

If the exhaust port is installer horizontally, the outside wind may blow right into the exhaust port, reaching the combustion chamber through the exhaust pipe. If the wind blows into the combustion chamber, it will interfere with its operation and may cause the combustion flame to escape out.

Warmda Hydronic Heater, exhaust port facing down
Warmda Hydronic Heater, exhaust port facing down

When diesel burns, a small amount of water vapor is produced, which may condense on the exhaust pipe walls, forming droplets. Although this is just a tiny amount, the water droplets will accumulate inside the exhaust pipe if the exhaust port faces upwards.

At low temperatures, the water will freeze, reducing the diameter of the exhaust pipe, and affecting the combustion performance of the heater.

Lastly, the entire exhaust pipe should be slightly tilted downward. That will allow the water droplets to flow out of the heater through the exhaust pipe.

    16. How To Choose The Exhaust Pipe Clamp

The exhaust pipe clamp is another diesel heater part that is more important than it first seems. The quality of the clamp will determine how well it will hold the exhaust pipe in place.

Warmda Heavy Duty Stainless Steel Exhaust Pipe Clip
Warmda Heavy Duty Stainless Steel Exhaust Pipe Clip

When you drive the vehicle, you will go over bumps, and the clamp will be the only thing that will hold the pipe firmly in place, which is why it is essential to have a strong clamping force. A heavy-duty exhaust clamp will keep the pipe securely mounted to the heater.

Usage scenarios of Warmda exhaust pipe clips
Usage scenarios of Warmda exhaust pipe clips

The heater’s exhaust system is mounted outside of the compartment and is exposed to various corrosive substances. To prevent decay and rust, it is imperative to use stainless steel for exhaust clamps, and also screws and nuts.

    17. Choosing The Best Muffler Location

Customers often make a mistake and install the muffler at the end of the exhaust pipe. This is not optimal, as the muffler won’t properly dampen the exhaust pipe noise.

Installation location of exhaust muffler
Installation location of exhaust muffler

To have the best muffling effect, you should install the muffler in the middle of the exhaust pipe. For that reason, we recommend that diesel heater manufacturers should offer two lengths of the spiral exhaust pipe – short and long.

Use two different length exhaust pipes
Use two different length exhaust pipes

The exhaust pipe should also have a protector at the end, which will prevent insects from getting inside the heater, nesting inside the heater combustion chamber during the summer when the heater is not in use.

Add a protective cover to the outlet of the exhaust pipe
Add a protective cover to the outlet of the exhaust pipe

    18. Exhaust Muffler Installation Notes

You have probably noticed that the exhaust muffler has a small hole in it. That hole allows the condensation droplets that form when diesel burns to flow out. But, for that to happen, that hole needs to be facing down when you install the muffler.

Direction of exhaust muffler
Direction of exhaust muffler

Note that there are exhaust mufflers without a hole too. These mufflers are not entirely sealed. For the water droplets to flow out, you need to install the muffler upright, and the water will go through the gaps in the muffler.

    19. Things To Watch Out For When Installing The Oil Tank

Many diesel heater manufacturers choose a white plastic fuel tank. But, this type of tank is not ideal.

Ultraviolet rays can easily penetrate the while plastic and reach the diesel fuel inside the tank. Exposing the diesel fuel to the UV rays for prolonged periods will lead to fuel deterioration. This fuel will clog the heater’s fuel delivery system, filter, and pump, as well as the heater’s fuel inlet.

Warmda black UV resistant plastic fuel tank
Warmda black UV resistant plastic fuel tank

If you are going to use a clear white fuel tank, make sure it is installed where sunlight won’t reach it directly. Also, consider adding a cover to the fuel tank to reduce the UV damage even further.

Warmda stainless steel fuel tank
Warmda stainless steel fuel tank

But, if you can, choose a black plastic fuel tank. Even better, opt for a stainless steel tank. These materials will protect the fuel inside the tank, preventing deterioration.

Warmda white translucent fuel tank
Warmda white translucent fuel tank

Also, consider choosing a tank with a lock. That will prevent pranking neighbors from messing with the tank and will also prevent theft.

Warmda fuel tank lock
Warmda fuel tank lock

Issues With Installing The Fuel Outlet At The Bottom Of The tank

Many manufacturers recommend you to install a fuel outlet at the bottom of the tank. That will connect it to the fuel delivery line directly—a simple installation method and very easy to use.

But, this method has some major downsides:

A. Тhe Risk Of Diesel Leakage

The fuel tank is made of plastic, while the outlet is usually made of aluminum or iron and is mounted underneath the fuel tank. Because of the position, if the outlet is accidentally hit, it can be deformed by force, leading to fuel leaking out of the tank.

Solution:

A small hole is punched out of the gas cap, and the standpipe enters the fuel tank through the hole in it. This method will prevent any fuel leaks from happening.

B. Fuel Pump Sucking Contaminants IN

Diesel fuel sometimes contains contaminants, which is why it makes sense to install the fuel tank standpipe with some spare room at the bottom of the tank. Leaving 2 cm (3/4 inch) between the bottom of the fuel tank and the standpipe will allow any contaminants inside the diesel fuel to settle at the bottom of the tank. This will prevent them from being sucked into the fuel pump, clogging it up and preventing it from working correctly.

    20. Fuel Tank Standpipe Installation Considerations

The fuel tank standpipe is usually installed on top of the vehicle’s fuel tank.

Some people think that drilling holes in the vehicle’s fuel tank will damage the tank. That’s a common misconception, and drilling holes won’t affect the tank at all.

Warmda fuel tank standpipe
Warmda fuel tank standpipe

You just need to make sure that when you install the fuel tank standpipe, there is a distance of more than 2 cm (3/4 inch) between the fuel tank standpipe and the bottom of the fuel tank.

This is to keep substances that have settled in the bottom of the tank from being drawn up and clogging the fuel pump.

    21. Things To Keep In Mind When Installing The Intake Filter.

The intake filter filters the air entering the heater’s combustion chamber, removing dust and other contaminants. It also prevents carbon buildup in the heater.

The positions of the combustion exhaust gas outlet and the combustion air inlet are opposite
The positions of the combustion exhaust gas outlet and the combustion air inlet are opposite

The air entering the heater combustion chamber passes through the filter’s tiny holes. This not only removes contaminants but also results in the heater operating much quieter. Because of this, many manufacturers call this part “intake air muffler” instead of filter.

When installing the intake air filter, you should put it away from the heater’s combustion exhaust pipe but also the vehicle’s exhaust. Installing the intake air filter further away from the exhaust systems will prevent exhaust gas from being drawn back into the combustion chamber, creating problems with the combustion process.

    22. Remote Control Precautions

Every heater is paired with an appropriate remote control and control panel before it leaves the factory. Some remotes come with batteries; others don’t, which means you will have to purchase and install them yourself. Also, make sure you are using the appropriate remote control with an adequate heater – swapping remotes with different heaters will not work.

Conclusion

After as many as 22 tips from above, you know all there is to know about diesel heater installation. But, you also learned how to choose heater accessories.

Whether you are a diesel heater dealer, a vehicle service technician who installs the heaters, or just a customer, you will be able to install a diesel heater with ease after reading this article.

When installed properly, a quality heater will work without any issues for 8-10 years. All you need to do is to start the heater every two months, allowing the fuel and combustion system to work for 15+ minutes, and that’s it.

I hope that this article helped and that you have learned many useful tips about diesel heaters. If you liked it, don’t hesitate to share it with other people who can make use of it, as it is likely to help anyone who has a diesel heater mounter on their vehicle. Feel free to let me know if you have any questions regarding the Warmda diesel heaters. Thanks for reading!

Hi,This is Eric, the author of this article.
As an experienced heater enthusiast, I have been in the industry for 25 years.
You can find most of what you need to know about heaters here.
If there are any inappropriate descriptions and expressions in my article, please send me an email in time. I will revise my article.

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