Espar D2 - All carbed up!!

I’m in need of some expert advise. I have a d2 heater that has given me fits. And now for the second time (6 months apart) I’ve opened it up again to service the unit and found it absolutely clogged with carbon. See before and after photos. Not sure how we got any heat out of the thing on our last 2 weekend trips but it finally threw repeated 52,54, and 13 errors with tons of smoke so it was past time.

The exhaust pipe is within spec with one gentle 90degree turn to get the fumes going horizontally out of the van then the muffler and a straight run to the drivers side behind the door.

The fuel pump is working well and no bubbles in the line.

After a clean out the heater tends to run like brand new minus the occasional overheat if I get too excited about my temp setting.

We live at sea level and tend to trip under 1000ft. I did install the HAK just in case.

Happy to include more details but this is a good start.

Are you only running it on low power for long periods? You need to run it on full power frequently (once a week) to avoid carbon build up.

Some suggest running it full blast for 15-30 minutes at the end of every use. Others suggest running kerosene fuel occasionally as a cleaner. Both suggestions seem reasonable and may help.

Yeah, thats not normal, even with running on low power a lot. How many hours since the last cleaning?

You need to check your intake and exhaust runs, blow through them, any obstructions? Muffler especially?

If the main case of the heater is distorted and the blower fan rubs against it, it can slow it down enough to cause low flow. Check it for rubbing.


You must clean out the burner core screens, and the glow plug screen (don't forget the small hole). Both can be cleaned using a propane torch, you want to heat the interior until it glows, then direct the torch down the pipe over the round flame stabilizer. This will slowly burn out the carbon the screen. If either of these are coked up, the fuel won't vaporize properly.

IF - your intake and exhaust are breathing well - then perhaps over-fueling. Check that you have the correct fuel pump for an Espar Airtronic. And do a fuel delivery test as described in manual. Angle set correctly on pump? Is pump connected to a pressurized return line, or does it draw up a fuel stand pipe?

For the elevations you are at I would run without the H-kit in order to reduce the variables until you can sort this out.

And that brings up - what year is the D2? And are you using the H-Kit or the previous device - the "High Altitude Compensator"? To tell them apart - The Compensator connects to the fuel pump, the H-Kit does not.

Could you post pictures of the intake and exhaust runs.

Wow, great insights. To answer questions and fill in some details:

Van - 2018 144 4x4 Cargo

The Espar D2 and HAK were purchased in the fall of 2018 so are relatively new (but not the latest heater with integrated HAK).

The pump came with the kit - so it's sided and proper to the unit.

The controller unit is an Easystart Timer.

Exhaust run photos attached, you can also see the intake which does a loop and then faces the ground to prevent moisture /objects from entering. I'm half tempted to pull the muffler and live with the increase in volume in exchange for the less restricted airflow.

Fuel - the fuel comes off of a T-fitting splitting the feed going to the heater booster, it's off the aux feed on the tank. It's not under pressure. The pump angle is within spec although I think the 15* thing is BS because if you park your rig at an angle ever (my driveway is sloped) you would be off angle and have issues. The angle of parking doesn't seem to have an effect on heat.

Running on High - With the Easystart Timer all I can do is set a temperature and let it run. So typically when we go out for a weekend or if I'm out for the day I start it up in advance and it runs on high to get to temp and then idles to maintain temp (1-5 days). Is there a way to force the heater to run on high? Or to cycle off once temp is reached?

Cleaning the unit - yesterday I performed a full service. New diffuser screen, scrubbed the inside, torched and re-assembled. No plastic parts are warped. It fired on the first try once re-connected.

I dont' think it's normal to have this much carbon every 6 months, even running on low. I have a Planar heater in my work van and it runs on low most of the time and has never gotten this bad internally.

HAK - I think you may have nailed it here. The HAK could be goofy and since in AK most of our time is at or near sea level i should pull this unit until we are down in the states.


I'm open to more advice but I think my next steps will be to remove the connection to the HAK and pull a wire brush through the exhaust and see if that has restrictions as well. Possibly remove the muffler and see if the noise is over the top.

Thanks!

I need to look at the install manual, but your intake and exhaust runs are likely way too long. The full 270 degree bend on the intake isn't helping either.

I would reroute your exhaust to exit the passenger side. Either that, or you need to use a larger diameter pipe for the majority of the run.

Removing most of the intake pipe could help, obvious you need to route in such a way that road debris can't get thrown into the intake.

You may also need small drain holes in the exhaust where water can accumulate.

On the intake, make sure the end is not obscured, it needs free air for 1.5-2" in all directions.

Edit: I looked at the manual and it says 2 meters is the max length (combined). I still think shortening will improve the issue.

That is a lot of inlet and exhaust tubing. In may be within specifications - BUT since you are having problems that could be caused by that length I would work on shortening it. I'd hit the inlet first. It really only needs a short length with a 45 bend in it to keep direct debris out. Try that first.

If you have trouble again I would increase the exhaust tubing diameter. This will still let you get it out the other side. My layout is much different as I have a class C - but I have a short length of flex and then go into a long length of larger diam EMT conduit. The conduit is also smooth which further cuts the resistance. Lastly, you may have low spots where condensation builds up further cutting diameter - really bad if it starts freezing. My conduit slopes in one direction promoting drainage. If you can't straighten out dips, then drill a very small hole to allow drainage.

Ah - MWD types faster than I. What he said.

Its not in the install manual, but the repair/service manual says that the intake and exhaust can have no more than 6.5ft combined, and 270 degrees of bends combined. Its confusing as the install manual says 2m for both intake and exhaust, but thats 2m total, at least for the 25mm pipe.

It also mentions that if the pump is mounted wrong it can inject to much fuel?

Also the horizontal muffler may be an issue. There is a short perforated U tube in there wrapped in fiberglass/ceramic fluff. If this is pooling condensation it may block off half your diameter. The muffler has a bottom "drain" that would work if oriented vertically.

I don't mean the inlet and outlet are vertical - but that the "flat" plane is rotated 90 degrees (from how it is now) - with the U on top.

Midwestdrifter said:

It also mentions that if the pump is mounted wrong it can inject to much fuel?

Click to expand...

I recall that from someplace too and it was a pretty significant amount if I remember right.

I hadn't thought about shortening the input side. I can make that way shorter, shouldn't suck anything up.

Exhaust to passenger side - Yeah I see this as a typical install but I'm really opposed to having the exhaust next to my slider where we come in and out.

Re - larger diameter tubing. I actually did that originally. After the muffler I stepped up to 2 inch smooth flex and ran 10 feet out the back of the van along the vehicle exhaust. The issue was that the back pressure wasn't great enough and the the exhaust didn't move out fast enough, the slower moving fumes cooled quickly and condensed on the inside of the pipe and on a cold week it froze solid creating a plug. - first overheating and shutdown issue - Luckliy I had run it next to the van exhaust and running the van thawed out the plug....

So yes - it's long BUT it's within spec and so it should work.

I hadn't thought about swapping for smooth conduit, that could maintain the run, keep a consistent slope and as you say reduce drag.

That's an easy swap. Thanks

One other aspect to look at, and considering that the combustion intake/exhaust share the same motor as the heat exchange intake/exhaust, and that your error codes are related to 'overheating', which is a bi-product of said motor running below optimal speed, is whether the heat exchange intake/exhaust hoses are within spec. or air flow subjected to excess resistance.

You may have here what is known as 'the perfect storm'.





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True above for the overheating warning (inadequate heat exchanger airflow). For the combustion though, I would wonder that with the fan speed sensing magnet that the D2 ECU is running the blower at the proper speed for the combustion flow and so inadequate air for combustion maybe points more towards blockages???????

I just don't know if fan speed feedback is continuous or only checked at start up. I guess a rubber finger on the blower fan should throw an error and we'd know.

Restricted combustion air flow also can cause overheating in a marginal installation. The exhaust does carry away a bit of heat (about 20%).

I agree though, checking the fan housing for rub marks, and spinning by hand is a good idea. Also note that some rubbing may only occur when the housing heats up.

Thanks for the feedback. It looks like I'll be shortening the air intake and then pulling the exhaust to see if it has any blockages. I'm tempted to dump the muffler and then run a straight conduit to reduce flow restrictions. When I knock the exhaust pipe now it dumps carbon buildup so I can only imagine what the inside of the muffler looks like. ;S

When disassembled I didn't see any out of the ordinary marks on the fan and it runs quiet - i assume I'd hear a rub.

I agree with others, shortening your intake and exhaust plumbing will result in less carbon buildup.

Longer plumbing = less air flow = colder combustion temps = carbon buildup.

I ran my combustion air intake line directly into the hole in the frame which is visible in your picture. This makes for a short intake line, limits any debris, and minimizes intake noise.

My exhaust extends the minimum distance, with muffler, exiting adjacent to the engine exhaust pipe. I have not noticed any significant exhaust smells but then I usually have the slider closed when heating the van interior.

The HAK reduces fuel flow for a hotter burn so it should be helping the situation at elevation.

I also avoid idling the D2 for extended hours preferring to run the heater hard and then shutting it off overnight.






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