Espar Troubleshoot Help

chrismac

Member
I've combed most all treads pertaining to troubleshooting the 'auxiliary heater' and have completed what I perceive all test to get a running espar. But now I need some help to close in on getting it to run consistently. I have a 2006 cargo 140 with 210k.

I have two heaters, one control unit does not respond at all, here I may consider the 'de-pot' procedure outlined in this thread:

https://sprinter-source.com/forum/showthread.php?t=66368

My second heater control unit was in the van and had worked well for one winter, and then last winter inconsistently. So a month ago I took it apart, cleaned, and measured resistance to the glow pin, flame sensor, and the temp sensor (overheat I believe). I picked the best looking components as they all measured similar. Installed the heater and it did not fire. I gave the fuel pump 9v and it ticked away with my application of power, fan spun smooth with the 9v too. I tried it again yesterday and it fired up and ran great for 5-8 minutes before slowing down for a short period of time, and then stopped running. So it does appear to be functioning, but something is not liked after running for a bit, as that is similar to what I experienced in recent times. I ran it off of my switch to run without the engine running; the DPDT switch installed to work with the REST function. Which works great.

Here are my questions I need help with. I measured the resistance but don't quite understand the values on the meter scale. Do these look right or in realm of good function:

Glow Pin = .5 on a 200 ohm scale - this means 100 ohm?
Flame Sensor = 1.04 on 20k ohm scale - this means 20.8k ohm?
OH Temp = 14.97 on a 20k ohm scale - this means 300k ohm?

And now that I think about this I believe I measured that OH Temp wrong; across the plug so I was going blue/blue and red/red, where as you would want to measure across the two, red/blue right? But there are two of each wire, how would you measure that, and would it need coolant in there to measure correctly? I measured these at the plug inside the heater on the bench right before plugging into the control end to make sure wiring was good before assembly.

Would you want higher or lower resistance for the Glow Pin and Flame Sensor?

The fuel tank was right at 1/4 full, but I am thinking if it was low enough it wouldn't have let if fire at all?

Since I am running the heater without engine running, is it possible there would be a voltage cut off to maintain starter battery minimum? I am going to install a switch I have for my auxiliary battery that charges off the alternator, to be able to connect the coach battery with the starter battery to aid in starting. This might help have power for pre-heating without the engine running.

I have attached pictured of my resistance measurements. Does not look like I can post a .mov, but on my Flickr page link below, you can see a 13 second video of if running beautifully. The photos are there too along with other van stuff like black death.. oh the fun! Thanks to everyone keeping the espar threads going and any help in advance. In the mean time I will put some fuel in it and try driving. I wish this thing ran as consistently as my D2 air heater!

Chris
https://www.flickr.com/photos/146749005@N04/albums/72157680328802126
 

Attachments

Patrick of M

2005 T1N 2500 (NA spec)
Keep it simple, put more fuel in before scratching your head too much. Lack of coolant flow would also cause the Espar to turn off, I presume the Espar does this by noting difference in the temp of the inlet and outlet temp sensors, if they are both static it wouldn’t presume no coolant flow, a partially failed temp sensor could cause this. Speaking of coolant flow, my Espar will run using engine on coolant flow, so unless you have yours rigged to run engine off, coolant flow should not be a problem. Good luck.
 

chrismac

Member
Good point on the coolant flow. I will go fuel up and make sure my coolant is topped off.

Yes, I am rigged to run without the engine running. The REST function engages running the small coolant pump and interior cabin fan runs, while the DPDT switch commands the heater to run. There is a tread on here that has a nice diagram on how to wire it up. Thanks
 

Patrick of M

2005 T1N 2500 (NA spec)
Good point on the coolant flow. I will go fuel up and make sure my coolant is topped off.

Yes, I am rigged to run without the engine running. The REST function engages running the small coolant pump and interior cabin fan runs, while the DPDT switch commands the heater to run. There is a tread on here that has a nice diagram on how to wire it up. Thanks
So are you testing the Espar with engine running? If it works engine on but not engine off, it’s probably your aux coolant pump (though low bat voltage would also cause a shutdown).
 

chrismac

Member
I am testing the espar without the engine running. That's why I thought it might cut off to maintain battery for an engine start. I added over a liter of coolant to the system, so that might make a difference as you pointed out. I guess I lost more coolant than I thought taking that heater out now 4 times! I'll fuel up and drive today or tomorrow. thanks
 

Patrick of M

2005 T1N 2500 (NA spec)
To clarify: I was not referring to low coolant, but lack of coolant circulation.
Try starting the Espar while the engine is running.
I know from experience that my van would run the Espar while the engine was running when my aux coolant pump was not working.
Engine off and the Espar would start but then shut down at some point during the start cycle.
I have the 7 day timer and the diagnostic wire, so it was easy for me to diagnose the no start.
Finally, my reading here at the forum indicates that aux coolant pumps sometimes only last a 1 year or less.
 

expcourier

expeditious
It could very well be that your heater is functioning normally because it runs and then shuts down. A common reason for this is overheating of the heater booster due to lack of coolant circulation. The circulation pump on the firewall under the brake booster is your probable culprit.

With the key off. Press the rest button and check for coolant circulation. Not only will you hear the pump running, you will hear the coolant moving. I recently bought this pump for $56 online. This pump is a common failure item.

Please post what solution eventually works for you so that others will also benefit.
 

chrismac

Member
Ok, I've run it now a couple more times with engine running and without the engine running. I get the same result with both; it runs great, sounds great for that 5-10 minute window, then slows up, make a wheezy effort to keep going, roars back up for a short spell or two, sputters like it want's to keep going, and then stops running. I can reset it with the fuse trick and it will try again, to the same conclusion.

The first couple times with the engine running is smoked a lot. I notices some moisture dripping form the combustion exhaust into the muffler and wondered if the tube or muffler had water or coolant in them. I pulled the exhaust tube off completely, and I get the same behavior except the smoke has subsided.

I'm getting coolant flow with the engine off fine. I replaced the auxiliary pump on the firewall a year or two ago when I got it working for the first time, it seems to be pumping fine. I'm not sure what to think at the moment. Thanks for the input.
 

Nautamaran

2004 140” HRC 2500 (Crewed)
Mine made huge white clouds the first few times I ran it, but I got lucky as it settled down on its own.
With the sputtering, my first thought is that your unit’s fuel evaporator screen may be clogged up with soot, restricting airflow. I don’t believe mine has ever blown liquid? Running it a few times with the exhaust pipe off may let it breath better and burn itself clean.

Or not... a shot in the dark on my part.

(It’s normal for them to throttle down once the coolant temp rises, but five minutes is too quick for that)

-dave
 

Patrick of M

2005 T1N 2500 (NA spec)
I’m going to suggest this only because it worked for me. Try going for a drive on a nice bumpy road with the Espar running, lazy mans clean out. If you are sooty in there is might break it loose with the heat etc...I have had good luck with other diesel furnaces just disassembling, cleaning up, and reassembly. There is a gasket in that will probably need replacing if you open up the blower section.
 

Midwestdrifter

Engineer In Residence
You can run some kerosene through the unit, just get a short hose and connect it to the fuel pump inlet. That may do the trick.
 

chrismac

Member
Mine made huge white clouds the first few times I ran it, but I got lucky as it settled down on its own.
With the sputtering, my first thought is that your unit’s fuel evaporator screen may be clogged up with soot, restricting airflow. I don’t believe mine has ever blown liquid? Running it a few times with the exhaust pipe off may let it breath better and burn itself clean.

Or not... a shot in the dark on my part.

(It’s normal for them to throttle down once the coolant temp rises, but five minutes is too quick for that)

-dave
Correct me if I'm wrong, but I was of the understanding that the stock auxiliary heaters did not use a screen, more like a 'drip tube'. I'll have to revisit the 'espar files' on that one. Before re-assembly of the heater, I cleaned it thoroughly. It's tough to clean that burner tube as it's all fairly concealed, but I might investigate that some more, maybe soak it in parts cleaner or something as it does seem as though something gets gummed up or clogged after a short burn. Thanks
 
I am having the exact same issue as you. Did you wire your timer for diagnostic? You would be getting a code F17 I bet. I am about to try the unit circulating coolant in a bucket to see if coolant is just stuck somewhere. I am suspecting the 3 way switch that isolates the heater when the engine is running to constantly be closed, isolating the aux heater. I get a hot output line from the heater, but the coolant intake remains cold. I'll let you guys know
 

chrismac

Member
So yesterday I removed the heater again and completely cleaned the burner tube. I basically soaked it in carb cleaner and blew it out with air. The soak fluid was dirty and some chunks of black residue swam free.

I re-assembled the heater and ran it with the engine off, it ran great, longer than I had been getting it to run previously. I turned the heater off, let it spool down, and then tested it with the engine running. It ran fine for a while, and then sputtered and shut down again reaching a coolant temp of high 80's. Then would not restart.

I feel like the unit is as clean as it can possibly get so I'm not sure if running kerosene through it will do anything. At this point I'm starting to conclude that unit has a problem somewhere in the control and is beyond cleaning or replacing parts; it runs awesome for a short spell. I will try resetting it and test run it a few more times, but am at wits end trying to get it to be reliable.

If you have not seen it, user expcourier found a (sounds like a 'direct') replacement from Europe that indeed worked. At this point I see this as the best resolution and I will likely follow. Here is the thread with great info:

https://sprinter-source.com/forum/showthread.php?t=69807

Also, kentonius wrote up a thread about replacing a stock espar with a unit from Heatso I believe here in the States. This is written up with use in conjunction with a 7 day time, which I do not have so I need to re-read that thread and see if there is anything about it working without the timer, but also looks like a good option.

https://sprinter-source.com/forum/showthread.php?t=69445

Thanks for the input, I'll conclude this thread with what I go with in the end.
 

chrismac

Member
I am having the exact same issue as you. Did you wire your timer for diagnostic? You would be getting a code F17 I bet. I am about to try the unit circulating coolant in a bucket to see if coolant is just stuck somewhere. I am suspecting the 3 way switch that isolates the heater when the engine is running to constantly be closed, isolating the aux heater. I get a hot output line from the heater, but the coolant intake remains cold. I'll let you guys know
I do not have the 7 day timer so do not have the diagnostic capability. My switch is wired so that the heater and circuit is as normal or 'stock' when in the off position. I can't recall specifics about the wiring at the moment, but the switch works great, now if I could just get the heater to work great, I'd be happy.
 

expcourier

expeditious
I hate to repeat myself, but have you verified that coolant is actually circulating. Push your rest button and VERIFY that coolant is circulating. The espar unit will shut down by itself if the temperature gets too high, which will happen if coolant isn’t moving. The fact that it runs for a while before it shuts down might be an indication of overheating the espar unit. The coolant circulation pump on the firewall under the brake booster is a common failure item. Some have reported on this forum that they can hear the pump spinning but coolant is still not circulating.

The pump listed in the photo is an exact replacement for my 2003 T1N OM612 Sprinter. They delivered it to my door in one day for free. Their price is way below others I researched.

Hate to see you waste time and money if all you need is a new pump.

Good luck and keep us posted. Following up helps others also.

Just realized you posted that coolant was moving. Sorry
 

Attachments

Last edited:

Nautamaran

2004 140” HRC 2500 (Crewed)
I’d still pursue the “coolant has reached temp” angle to its end...
Perhaps the temp sensor is faulty, or flow isn’t reaching the furnace properly?
Can you measure the exit hose temp with an IR thermometer, or even with a meat thermometer wrapped in a rag around the coolant line. If that gets above 180’F you’ve got a circulation issue... if it consistently cuts out at a particular temperature look closely at the temperature sensor and its wiring/connector.

Good luck with it... these things can indeed be maddening!

-dave
 

chrismac

Member
I hate to repeat myself, but have you verified that coolant is actually circulating. Push your rest button and VERIFY that coolant is circulating. The espar unit will shut down by itself if the temperature gets too high, which will happen if coolant isn’t moving. The fact that it runs for a while before it shuts down might be an indication of overheating the espar unit. The coolant circulation pump on the firewall under the brake booster is a common failure item. Some have reported on this forum that they can hear the pump spinning but coolant is still not circulating.

The pump listed in the photo is an exact replacement for my 2003 T1N OM612 Sprinter. They delivered it to my door in one day for free. Their price is way below others I researched.

Hate to see you waste time and money if all you need is a new pump.

Good luck and keep us posted. Following up helps others also.

Just realized you posted that coolant was moving. Sorry
No worries. I replaced that pump 1-2 years ago. That does seem like the largest culprit, but I'm having the same issue with the engine running. I feel if flow was an issue with engine running, I'd have other problems. Is there a way to tell without putting in a clear line or something? The pump is humming, the lines are vibrating, and it sounds like coolant is moving, but still hard to tell.
 

Top Bottom