Esbar D7L - How to service burner?

[Diep]

I've got an old Espar unit, D7L. This is the big orange bus heater. It fires up well, smokes very briefly and then runs great for a while. Then it will suddenly start smoking badly for a minute or two. Usually shut it off when that happens but no problem restarting. It runs good again for half an hour or more before doing it again. I would like to get inside to take a look at the burner, screen, etc. I hear these need regular maintenance/cleaning and maybe that will improve things. I realize that with any major problems this is a paper weight but it seems like it runs decently. Maybe just dirty and loses flame occasionally.

The question is how do I get in there? I pulled the intake end off and removed the fan impeller and the motor. The burn chamber seems to be sealed from that end. Then I pulled off the output end and that's a mile away with the heat exchanger in there and doesn't look promising either. There is a service panel on the top that I haven't removed. It looks like it just gives access to the wiring connections inside.

Does anyone have a tip on how to service this guy?

 

[Portage_Bay]

AMC Cliffv's in Seattle. AMC Cliffv's Marine Service he's honest and fair. A true expert in those older systems. Went through my old D8 dinosaur for about $500. Runs as good as new.

 

[Bmarler]

Could easily be a fuel problem as well. Check for air bubbles in the fuel line. If there’s a filter on the pump inlet, clean it out or change it.

 

[helm]

We had Thermo King service our Espar heater in Stockton. They did a great job. If you have a Thermo King dealer nearby, they should be able to service it for you

 

[Diep]

Thanks for the tips so far. I'll double check the fuel line. I didn't notice a filter when I looked at it before.

A good chunk of the fuel line is clear so I should be able to watch it for bubbles.

 

[Bmarler]

Thanks for the tips so far. I'll double check the fuel line. I didn't notice a filter when I looked at it before.

A good chunk of the fuel line is clear so I should be able to watch it for bubbles.

many times there's a mesh screen on the inlet side of the fuel metering pump. some people take these out when installing and use an inline filter instead.

 

[Portage_Bay]

many times there's a mesh screen on the inlet side of the fuel metering pump. some people take these out when installing and use an inline filter instead.

I was advised by AMC Cliffv's Marine Service to remove the inline filter. The reason is they trap air causing air bubbles downstream of the inline filter. The mesh filter is easy to change on the D8.

 

[Lepke]

Is there a small inline filter? Sometimes they pick up debris and slowly plug. When the heater stalls, the fuel flow stops and runs back to the tank, flushing the debris from the filter media.

 

[Diep]

Unit is back together. There is no separate inline pump - just the one that inserts into the base of the fuel pump. There are a few bubbles in the line.

Called into AMC CliffV's to see if they had a new filter. The takeaway was yes they have a filter but it isn't likely the problem and that the air bubbles probably aren't either. They can rebuild the D8's but no one really has any parts for he D7's anymore. Probably the atomizer (?) is malfunctioning.

Still might pick up a filter since its cheap and give it a try.

 

[Bmarler]

The atomizer makes a mist of the fuel so it combusts more thoroughly.
There have been a few different iterations of burners, some with fiber rings that can disintegrate on removal. Not sure what the d7 burner looks like, but if it’s just not working, it’s worth taking it apart and attempting to clean. Cliffs isn’t the only place that might have a piece of this or that for a d7.

 

[Bmarler]

I’ve talked to this guy before: D7/D12 Parts
He used to work with boat electric and is pretty sharp on the older models.

 

[Portage_Bay]

Some links that may help
D7L technical manual
D7L Atomizer
Obsolete heater parts

 

[Diep]

Thanks for the links guys! CliffV was going to link us to someone who knew more about the D7's - I'll bet it is foenix. We'll talk to him too and make a plan.

I'm inclined to try the filter first. The pickup is at the very lowest part of the tank and the pump is only about 6" up from there. I could see it pulling some crud pretty easily. If that fails maybe get the unit out and try to work on it at home.

Hoping to limp this unit along a little bit but not throw big $ at it. Long-term we are thinking about pulling it out and going with a hydronic system.

 

[AndrewAdams]

Just getting a service person to think about helping you or loosening a single screw on that espar will cost you more than throwing it in the ocean and replacing it with a Chinese diesel heater like a Vevor. Basic service on my wallas heaters used to be $350. Replacing them costs $100 before the tariffs.