diesel heater service

[turf]

my diesel heaters hasnt run for a bit over a year. not for trying, it just hasnt started successfully. the last time it ran was on my way home from the october eclipse in 2023.

well its getting cold and i want to use it again... so time for service. its been clogged up before, so i kind of suspect the same issue, but idk. before i was able to clear it by removing the glow plug and spraying a can of brake cleaner down into the hole.

this time, my brake clean trick didnt work.... so time to trouble shoot.

the diesel heater is Planar brand. its a russian company, the heater has done fine for me, but occasionally, high altitude causes issues with smoke and clogging.

in another thread someone reccomeneded not using diesel fuel additives when using the diesel heatrer, and i agree. any additvies make the thing smoke like cheech and chong. its not worth the price of the additive.

i contacted planr, and the sales guy sent me a troubleshoot checklist.
he suggested checking 3 items,the fuel pump, the glow plug/screen, and the combustion chamber.

the fuel pump check tested faulty. when running, the pump barely put out a drop per click of the pump. the sales guys said it should squirt pretty good, anything else was faulty. so i ordered and installed new pump.

still, no start.

its getting fuel now, but still nothing.... so more investigating.
the glow plug checked out fine. i removed the plug and ran an ignition cycle, and the glow plug glows good. however, the wires are heat damaged and brittle. it works, but may not survive being reinstalled.... its sketchy.

but still no start. so...
time to remove the heater. i unbolted it from the bus, and pulled it into the garage for a teardown.

the case came off easy. i removed the control unit. and i was left with the basic heater. a blower unit head and a combustion chamber/heat exchanger.

i removed the blower unit, inspected and put aside. it looks to be in good shape. between the blower unit and the combustion chamber is the ignition chamber. here i could see some heat damaged wires. turns out those wires are a part of the "flame sensor". i could also see the glow plug igition area and it was caked up real good with soot.

the i split the other half open and thats the combustion chamber. maybe my brake clean did good, because there were no obtructions/ soot and the chamber was surprisingly clean.

i had ordered that fuel pump a few weeks ago and finally got it installed and working. but now i need a few more parts, so i've ordered a new flame probe, glow plug and screen.

so, waiting on parts, re-assembly, and testing

today, my impression is that the heater failed because i was bad at replacing the heater covers when it was opened up. i dont think heat was supposed to be where the damaged wires are. my nearby grommets are baked and brittle.

failed fuel pump test
https://photos.app.goo.gl/kPevxfXB3NmxYfCb6

heater pics

[Cheezewhiz]

Different design than what I'm familiar with, is that the 5kw? I have a 2kw.

If it's possible to search posts ive made, I've linked a couple times to a diysolar forum, there's a fellow by rednecktech who does a great description of the best way to keep em running good.

Tl; couldnt find:

They want to run full-bore, as much air as possible, as hot as possible. Do a 'cleaning cycle' and ramp it up to max for 20 minutes before you shut it down.

Even with clean #2

Will still need regular service, ie, tear down, clean out, and probably new gaskets-and especially (in my experience) that screen around the glowplug.

Replacement parts are cheap for now, I suggest getting a whole extra unit, and a small handful of gaskets/screens/glowplugs.
If you got the space

And maybe the 5kw pump should kick more, but mine is only supposed to kick a drop of fuel for every click

[Cheezewhiz]

Also, that burn chamber is a motherfucker.

I have four different tools to clear **** out of mine.

A long screwdriver. A slightly bent pokey. A real weird, made that way, 90 degree bent spike. I don't remember the other. Just solvent has proven insufficient

[Cheezewhiz]

If you don't clear enough crap out, it makes a locus for more crap to form, real fast.

We ran ours sparingly for two or three years, and I've had to clean it 4 times this year-but! It's been days since the last time, i may have just got a batch of bunk fuel, our local station is sketchy af

[turf]

its a 8kw heater. it was the biggest at the time i got it, but now there is a 9kw. it was originally installed in 2013.

i had to look back at photos to see when it was out of the bus before. surprise, surprise , surprise...... this is the 2nd time its been out of the bus for cleaning, the first time was 5 years ago, yesterday.

so i guess it needs cleaning about every 5 years.

[turf]

my burn chamber was very clean. there was only 1 dime size spot that had collected any soot. im soaking it in diesel overnight and will post pics later, but the first time i opened it up , it was carboned up for sure.... not the issue this time. this time its looking like a broken sensor.

this is not a cheap chinese heater. cant afford to have a spare sitting around. but for the price of the glow plug and fuel pump, i probably could have bought a couple of the chinese kind.

maybe i should have got a cheap chinese heater instead of fixing this...idk.

[Rucker]

Someone said they were selling for less than a hundred bucks on Amazon-that's true, just checked.

Buy two, and your downtime willl be no more than a couple of hours.

[turf]

yes, i see a vevor 8kw for $87.

right now im a bit over $300 into the repair.

[Rucker]

The challenge is real. I am always juggling a few scenarios like this.

Here's the principle (you may already have heard of it):
https://asana.com/resources/sunk-cost-fallacy

So a few years ago I bought an Onan 6.5K generator, 'needs work'. After a couple hundred in parts it works but is not set up for easy use.

Last week I see the same Onan generator on FB Marketplace for 200 bucks, works. My brain tells me just buy that one, but my other brain says 'no way will I cop out, I'm going to fix mine and win this battle'.

Dilemmas, dilemmas.

[turf]

ahh, thanks, interesting read.....

ive heard of the concept before but appreciate the reminder. really, bus building is an exercise in this.....

i dont know that the chinese replacement is the same. the planar heater was built in a very tight area, changing vent pipes or moving the location even a centimeter would be difficult to impossible. so $300 to get the thing working like it is. or a $100 and a remodel.

i did consider the chinese heaters, but im slow now, and not interested in a remodel.

i would consider installing an additional heater.

its my money pit, and im keeping it.

[cadillackid]

this planar heater is similar to the second type of D&E heater I got (other thasn its an air heater and my D&E is coolant... these are very picky about that seal going back together correctly to the chamber.. or combustion heat makes it out and melts stuff.. the wires or the plastic shroud...

[turf]

i think you're right Caddy!

i further disassembled the heater yesterday. i removed the burn pot from the assembly that held it. and low and behold, in between the 2 was a compromised gasket. probably the reason that wire burned.

lol dang, i already ordered parts and didnt order this gasket. i got back on the website and started to order the gasket, $9. shipping $40. so $50 if i want the original.

ugh

fortunately, the picture of the gasket has a brand name of the material its made from on it. i orderded 10"x10" sheet of the flame proof material for $10 on amazon. and will make my own.

ugh


in the pic, the bottom portion of the gasket is damage i did. but the top part was like that. the wire was right behind the hole on the top part.

[cadillackid]

yeah you can make your own gasket.. probably use exhaust gasket paper.. remflex might be too thick, might not be able to get it back together.. often wodnered if you could use fire caulk.. its meant to expand and self seal any deficiencies when exposed to heat...

[turf]

i have fireplace gasket stuff on my bench. i just replaced a rope gasket on my pellet stove. i was totally thinking about not replacing the gasket and using that high temp[ gasket stuff.

the gasket that failed was papery.... i didnt do it any favors by soaking it in diesel. from russia, its probably just asbestos.

i googled "paper flame gasket material" and this popped up, simialr enough to the original pic.

as a back up i still have the gasket stuff

[turf]

all the parts arrived so im putting the heater back together.

started out by cutting out my new gasket. the gasket material is about twice as thick as before, but installs good enough.

one of the bolts that secures the gasket also secures my new temp probe. however since the gasket is thicker, the bolt isnt long enough to catch a nut that use to secure the probe. the fit is pretty stiff as is, and once closed up, i dont think there is an opportunity for that probe to work itself out, so im not going to worry about it...

if it fails,,, i was there once before.

i just worked a bit on it.... until my fingers were numb from the cold, so will finish up tomorrow and get install this weekend.....
supposed to get up to the 40s then.


reassembly:

[Iceni John]

In that short video clip of your heater's exhaust, what is dripping from the small tube just below the exhaust?

John

[turf]

its the fuel line for the heater.

the planar guy told me to check the fuel flow.... dripping was bad, squirting was good.

so after seeing the flow, i replaced the pump, and it didnt fix the heater. so i dug deeper. right now the heater is out so i cant test the new pump with the heater unit disconnected.

when i reinstall the heater unit, i'll do the same test, and check out the new fuel pump, before i attach the fuel line.

any smoke from the heater is just residual, since the fuel is pumping to the ground

iirc, the new pump is like 7 ml per click. i think a ml is about 20 drops. so it needs more fuel

[cadillackid]

a 50 or 100 ml glass graduated cylinder works nice for testing those pumps. count the clicks and see how much it fills up.

[Iceni John]

I don't know how much fuel Planar pumps move, but most "5kW" Chinese diesel air heaters' pumps move 0.022ml per pulse, and about 0.017ml for the 2kW CDHs' pumps. For example, at 2Hz a 0.022ml pump will move 158.4ml per hour. Your heater's 0.7ml is 31 times greater than a typical 5kW CDH's pump!

A "5kW" CDH is actually about 4kW output.

John

[turf]

i thought i remembered seeing a tag that said 7ml, but here is the description from the website:



Description
Replacement fuel pump TH11-6.8ml-12v, “silent”. For heaters Planar 4DM2-12, 44D-12, 8DM-12, 9D-12 and 14TC-Mini-12.

This pump operates with significantly reduced ticking noise.

https://planarheaters.com/product/a-...fuel-pump-12v/

my heater is the 8D - good for 30k btu's


here is the whole email from the planar guy -

That is a very old unit.
If you have not replaced a combustion chamber yet, you probably should.

You can remove glow plug, keep it plugged in. Start the heater, if glow plug glows from the tip down ¾ of its length, its fine.
If glows partially or just a tip, its faulty.
Test pump, remove fuel line from it and start the heater, pump should be strongly spitting fuel with every click.
If fuel drips its faulty.
If you need to replace combustion chamber, you would need gaskets, grommets, possibly sensors...
See links for parts