Diesel Air Heaters

"All-in-One" Diesel Heater
This is a 8KW (~ 27,000 BTU) Chinese-made Diesel Parking Heater. It’s an “all-in-one” heater because the heating unit, fuel pump, fuel tank and control panel are already assembled and mounted inside a steel case.  Most of these heaters are sold without the case so it’s easier to mount the components in an engine compartment or other tight space.

I’ve purchased a 8KW (27,000 BTU) “diesel heater” to heat my small garage workshop with.  I did not know that this kind of heater existed until very recently.  They are commonly used to heat the interiors of motor vehicles and boats without having to run the engine, so they are also known as parking heaters.  They are designed to be powered by 12 or 24-volt batteries, they are very efficient and they are apparently very safe if they are installed correctly.

My heater cost about $190 and it’s a Chinese knock-off of the much more expensive German-made Eberspächer and Webasto diesel heaters.  It’s an “all in one” diesel heater because the combustion chamber, fuel pump and fuel tank are already assembled and mounted inside a steel case.  Those parts are usually mounted separately so they are easier to fit inside a cramped engine compartment, underneath a vehicle, or on a bulkhead.  

The heater I purchased also has a higher heat output that most.  Most of the diesel heaters for sale on Amazon generate 5KW or about 17,000 BTU, and there are also 2KW and 3KW heaters.  They all seem to be about the same price but there’s a good reason for not buying a heater that’s a lot larger than what you need. I’ll explain that later.

Unlike the kerosene torpedo heater I’ve been using to heat my garage, a diesel heater doesn’t create any dangerous combustion fumes inside the heated area because the gases are vented outside through an small exhaust pipe.  So I had to drill a 1-3/4 inch hole in the side of my garage for a 1-inch stainless steel exhaust pipe wrapped in fiberglass heat wrap ($13) to protect the wood and seal the gap around the pipe. [Wear gloves when working with fiberglass heat wrap or you’ll regret it.]

With the heat wrap, the temperature of the exhaust pipe is about 330°F (165°C).  I’ve read that it’s about 400°F without heat wrap.  FYI, the flash point of wood is about 572°F (300°C).

The heated air coming out of the unit is about 140°F (60°C).  The 8KW heaters have 4 pipes that the heated air comes out of.  The heater comes with a couple of lengths of air duct that will fit over the pipes and I’m using them to direct some of the heat towards different parts of my workshop. 

I mounted a 12-volt power supply on the wall with some brackets that I designed and 3D printed.

I also had to purchase a $13.99 110/220 volt AC to 12-volt DC power supply because these heaters are designed to run off of auto or marine batteries instead of AC power.  A glow plug is used to ignite the combustion process and so a 10-amp power supply is needed for about the first 30 seconds.  Once the heater is started it only uses about 1 amp (~12 watts) for the fan and fuel pump.  I purchased a 15-amp power supply because it’s usually better to buy a power supply that can supply more amperage than you need. 

[My total investment is about $234, for the heater, heat wrap, power supply and taxes.]

Almost all of these heaters come with a remote.  I think this is a great feature because I can start warming up my detached garage before I go out to work in it.  The remote has a small color LCD screen and it has two-way communication with the heater, so not only can I turn the heater on or off, but I can see if it’s on or off, see the current air temperature in the garage, and adjust the amount of heat that that is being produced. 

The control panel on the heater also has a color LCD and it is very impressive looking.  But it’s not intuitive at all, although it’s fairly easy to use once you figure it out (except maybe for the timer functions). 

The torpedo heater I’ve been using for decades puts out 70,000 BTU, so it heats up my workshop very quickly.  But I’d like to stop using it because it’s very noisy and I have to keep a door partly open so that I don’t get sick or die from the carbon monoxide it produces.  It’s not very noticeable, but it also produces an odor that becomes very annoying after a while.  

But I won’t be able to stop using it unless I insulate at least part of my garage.  That’s because my new diesel heater doesn’t produce enough heat to make my garage comfortable when the outside temperature is in the low 30s or colder (-1 to 3°C) .  When it’s that cold I have to also run the torpedo heater, which has a thermostat.  Once my garage gets warmed up the diesel heater can keep it that way without too much help from the noisy and smelly torpedo heater. 

My diesel heater produces plenty of heat, but it has to overcome a cold-soaked concrete floor that can be 30°F (-1°C) or colder during the winter months, walls and ceiling with no insulation, and a large number of single pane windows.  FYI, 27k BTU is a lot of heat, the gas furnace that keeps my 2000+ square-foot home warm during western NY winters only puts out about twice as much heat (60k BTU).

When the outside air temperature is in the thirties, or warmer, the diesel heater can keep me warm and comfortable all by itself. 

Potential Problems

I haven’t experienced all these problems but I’ve heard they are common:

  • The instructions for assembling the heater and operating the controls are USELESS.  Mine came with an impressive looking full color manual but it was in German.  And the English version for my unit, which you can download here, isn’t any better.   YouTube videos are much more helpful and I recommend the ones listed near the end of this article.  BTW, it’s obvious from looking at older videos that the manufacturer(s) of these heaters have been steadily making improvements to them. 
  • The ring terminals on my wires were not crimped properly and the negative wire easily pulled out of its connector, which could have caused the heater to suddenly stop working.  Cutting off the power suddenly while the heater is running can cause heat damage to some of the electronics because the cool-down process that takes place when you turn off the heater properly won’t run.  So check the connectors and never turn off your heater by just disconnecting the power to it.
  • The glow plug can fail prematurely – I’ve heard that the Eberspacher Airtronic D2 glow plug is better quality and a direct replacement.  I’ve read that the Chinese heaters are a copy of the D2 and they also share some other interchangeable parts.  It appears, by searching Amazon, that Chinese replacement parts for their diesel heaters are readily available and are inexpensive.  However, most do not come with fast Amazon Prime shipping, so it might take a while to get them.
  • The intake and exhaust tubes come out of the bottom of the “all-in-one” heater that I bought.  There are metal legs that raise the case up to make room for them, but they aren’t long enough to provide enough clearance because you can’t bend the exhaust pipe very sharply without possibly damaging it.  So you’ll probably have to raise it more by putting wood blocks under them, like I did.
  • The intake tube and fuel line are very close to the very hot exhaust pipe.  So it’s important that you keep them from being melted by it.  I wrapped mine in heat wrap to prevent that and to  also protect the wooden wall of my garage, when the exhaust pipe goes through it. (It required a 1.75-inch hole)
  • The “All-in-One” heater that I bought has a 5-liter (1.3 gallon) fuel tank.  But only about 4-liters (~1 gallon) are usable because of where they mounted the fuel outlet.  Although, the location of the outlet does help keep water and dirt from getting into the heater.  A full fuel tank should last about 4 hours if I run the heater continuously at its maximum output, because the fuel burn at that rate is supposed to be .26 gallons / 1.0 liters  per hour. 
  • The thermostat does not turn the heater on and off like you might expect.  When the desired temperature is reached it will continue to burn a small amount of fuel and produce heat.  The problem is that running it on “low” for long periods of time can cause soot and carbon to build up inside the combustion chamber, which can cause problems. You can take the heater apart and clean the chamber, but there are some things that you can do to prevent it. 

    The best way is to use cleaner burning kerosene instead of diesel fuel.  This will also make the glow plug last longer.   I’ve also heard that regularly running the heater on high for 30 minutes before shutting it down will also help prevent carbon build up. 

    You also want to get the right size heater for your needs.  If you have a small space to heat then a high output heater will run in low mode most of the time, causing soot and carbon to build up.  It would probably be better to get a smaller heater than will run on “high” most of the time. 

    By the way, the German-made diesel parking heaters also suffer from carbon/soot build up. 

  • You can’t display temperatures in Fahrenheit.
  • The intake / room  temperature is inaccurate.  The sensor is located where it measures the air temperature after it has already been heated up a little by the heater.  This is probably because the air intake and exhaust pipe are very close to each other. 
  • If you’re not careful, you can buy an “All-in-One” diesel heater on eBay that is just an empty steel enclosure, without any of the parts needed to produce heat. 
  • You might get one with a fan that rubs against the housing because it got pushed back on the shaft.

Some of the things I’ve learned:

The pulse rate of the fuel pump controls how much heat is produced.  A higher pulse rate means more fuel gets burned, which means more heat gets produced. 

By default, the heater is in “pulse rate mode” and it will continuously heat at whatever that setting is.  The heater does have a thermostat, but you have to enable it.  You can switch to the thermostat mode by displaying the pulse rate and then pressing the OK and UP buttons at the same time.  You can then then use the Up/Down buttons to set the temperature.

The thermostat will reduce the heat output when the desired temperature is reached. Unlike the thermostat in your house, it doesn’t not turn the heater completely off.  It just reduces the heat output to low.

When you switch to the thermostat, the “pulse rate” drops to 3-something even if it had been on the maximum setting of 5.5.  This means the heater won’t produce as much heat as it could, which means you may never get to your desired temperature if it’s really cold and the room is not insulated well.  I’ve learned that the pulse rate that’s used in thermostat mode can probably be adjusted in the “advanced” menu.  One of the videos listed below explains how to access it.

You have to prime the fuel line the first time you run the heater.  You do that by holding the “OK” and “Down” button at the same time.  The fuel pump will then run for 2 or 3 minutes and then turn off automatically.  You can then press the “On” button and the heater will start.  The start up process takes a minute or two because the glow plug has to warm up and ignite the fuel, then the combustion chamber has to warm up before you can feel any heat.

 The Up and Down buttons are reversed, in my opinion, if they are located at the bottom of your control panel and are pointing left and rightThe DOWN button is the “right” arrow and the UP button is the “left” arrow.  Some control panels have the buttons located where they actually point up and down.

The heater will shutdown automatically if the battery voltage drops below a certain level, which I think is somewhere between 10 and 10.5 volts. 

My heater stopped working once and displayed an E08 “no fuel” error code, even though there was plenty of fuel in the tank.  I’m not sure, but I think a vacuum developed inside the tank that the fuel pump couldn’t overcome because the tank doesn’t have an air vent.  Since then I’ve haven’t screwed the fuel cap on as tightly.

The heater comes ready to run on 12-volts.  You can also run it off a 24-volt battery but there’s an “advanced” setting you have to change.

You set the time by displaying it and pressing the up/down buttons to change a digit.  Press the OK button to move to the next digit. Use military/24-hour time.

Recommended Videos & Links

Chinese Diesel Heater for a Workshop/Shed (5KW) (YouTube)

Chinese diesel heater all in 1 review & how i have powered it from mains electric no battery needed (YouTube) – This video shows the same heater I have, but with different control panel.  It’s also being used to heat a workshop.

How To Set Chinese Diesel Heater Temperature Controller Settings (YouTube) – This video shows how to enable the thermostat.  By default, the heater continuous produces an amount of heat that is controlled by the fuel pump “pulse rate.”

The video shows a different style control panel.  Some controllers have the up/down buttons on the bottom, and the left button is “up” and the right button is “down.”  Degrees are shown in Celsius and you can not change them to Fahrenheit.

Having trouble setting the timer? | Chinese Diesel Heater (YouTube)  – You can set the heater to turn on or off specific times every day.  You can have it turn itself off after it has run a certain amount of time. 

Diesel Heater Advanced 1688 Menu (YouTube) – There are some advanced setting you can change.  1688 is the most common pass code that is used to access them.  You’ll need to access these settings if you want to run your heater off 24-volts.

Chinese Diesel Heater Dismantle & Remove Soot [How to] (YouTube) – You might need to do this if you run your diesel heater on low for long periods of time, because carbon can build up inside the combustion chamber and cause problems.

“John McK 47” has produced a lot of videos about these heaters and he seems to be the expert you should go to if you’re looking for technical data or detailed maintenance and repair information.  Here’s the one he made about my heater: Chinese Diesel Air Heater Part 13 All in one diesel air heater.

The official Chinese Diesel Heater thread (Webasto Knockoff) (forum discussion)

Please tell me in the comments if you find videos (or webpages) that are more useful than these, if they’re concise and to the point.  I don’t like videos that take 20 minutes to tell you something should only take 5.

4 thoughts on “Diesel Air Heaters”

  1. Thanks for this post. I wasn’t aware of this category of heater.

    Apparently propane versions are available (natural gas?) and this might have appeal to me.

    Of course, propane heaters for trailers and motor homes have been around for a long time.

    Lots of info and opinions online, as there is about everything….

    Reply
  2. I’ve tried using several different kinds of portable propane heaters to heat my garage and this diesel heater beats all of them by far.

    The “torpedo style” propane heater was the only one that had a blower that blew hot air, like this diesel heater. The other two, a convection and radiant heater, only heated the area around them, and they got hot enough to burn you if accidentally touched them. And I was always afraid that the flame would somehow go out and they would then leak propane gas into my garage while I was away getting lunch or running to a nearby store for a part.

    I also hate buying propane because few places sell it and I always have to wait for someone to fill the tank. Sometimes I exchange a tank at Home Depot, but it’s still a pain. Almost every gas station seems to sell diesel fuel now so it’s quick and easy to buy. I have to go a little further for kerosene, which is what I burn, but it’s still easier to get than propane.

    The diesel heater also takes up far less space, even if you include the floor space that a 5 gallon kerosene container needs. The heater sits in a very small unused space against a storage cabinet and the air ducts allow me to direct the hot air where I need it the most. BTW, I use a small battery powered pump with an automatic shut-off to transfer fuel from the kerosene container into the heater’s fuel tank.

    I found out about Diesel heaters while doing research for a cousin that wants to convert a van and live in it for a while. Propane heaters for RVs and campers are expensive, one that can produce at least 30,000 BTU cost at least $700, about 3 times what my diesel heater cost.

    Reply
  3. Hi there,

    Nice to talk with you.

    We specialized in Eberspacher/Webasto Parts and Electric Air Conditioners for many years, and used for Trucks,Commercial Vehicles, RVs and Engineering Machinery Vehicles etc.

    All our products passed CE and TUV qualifications, and we only exported to quality markets as well.

    You could check our website, and please let me know if any question.

    Thanks and looking forward to your reply.


    Best Regards
    Reeves Li
    Business Manager
    QINGDAO RGY COMMERCE AND TRADE CO.,LTD
    Add:No.204 National Road, Chengyang District, Qingdao 266000,China
    Tel: 0086-531-55557430
    Cell: 0086-18560628679
    Email: [email protected]
    Web: http://www.qdrgy.com

    Reply

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