Espar D5 Repairs

Note: For installation information click here

Airtronic L "Troubleshooting and Repair Instructions"
Airtronic L "Installation, Operation and Maintenance"
Airtronic D2D4 Basic Repair Analysis
Airtronic Marine Installations
Espar Digi Controller Manual


With one more winter to contend with we want to make sure our diesel heater is going to be ready.  Over the last two winters we've averaged something like 2500 hours of non-stop running between December and early March.  Last year just as we were going to shut it down with the onset of warmer weather it decided to quit on it's own.  I let it go because it was no longer a high priority item and I had plenty of other stuff to work on.  As August rolled by I realized that time was getting away from me and decided to put the heater back up at the top of my priority list.

I did some preliminary troubleshooting and narrowed the problem down to the fuel metering pump.  It has a screen filter on the inlet and that was totally plugged.  I tried to clean it but punched a hole through the screen in the process.  That did give me better fuel flow but I still had errors and the heater wouldn't run for more than a few minutes.  I priced a new pump through our local supplier and they quoted me $300.  Uhm, sorry, but this little thing is not worth that kind of money.

This is a simple little piston driven pump, nothing complicated.  I saw the same pump priced on-line for $165.  I sincerely believe in supporting the local dudes but this was just ridiculous.  Even at $165 this thing is way over priced.  I shelved the project for a few weeks and gave it some thought.  This past weekend I opened up the manual and did some proper troubleshooting.  Following the error codes I came to the same conclusion, that the pump was bad, but I learned a lot about the system in the process.

Our D5 heater came with a small four button "digi controller".  To get the error codes you have to hold the top two buttons down simultaneously for about three seconds.  It'll then continuously cycle through all the codes in it's memory.  For this problem it showed #11 (under voltage cutout), #13 (flame sensor over temp), #48 (metering pump interruption), and #52 (safety time exceeded).  Espar has an excellent troubleshooting guide (Airtronic L Troubleshooting and Repair Instructions) which explains what to do for each code.  For code #11 I disconnected the main wiring harness connector "S1/B1" and put a volt meter across pins 1 and 10 where I saw 13.2 volts, just as it should be.  For #13 it suggests checking the combination sensor (flame and over temp) but it goes on to mention fuel quantity too and this ties in with the other codes so I moved on to the next one, #48.  This says to check the resistance across the two leads on the fuel metering pump.  It's supposed to read 9.5 ohms but mine reads 0.2.  I also noticed that code #47 suggests that if you have error code #48 then just go ahead and replace the fuel metering pump.  OK, I'll do that.  In another manual (Airtronic D2D4 Basic Repair Analysis) it mentions that the most common cause of metering pump failures is extended periods of non-use causing the piston to freeze.  I suspect this then causes the coil to short out and give the indication I see here.  We don't run the heater from March to December, pretty much nine or ten months straight.  I think that qualifies for "extended periods".  #52 is just a safety feature built into the program that only allows the heater to be in the start-up mode for a short period of time.  If it doesn't go into run mode within that time it switches over to shut-down mode to keep itself from turning into a lump of molten metal.  I went ahead and ordered the $165 metering pump on line.  It's worth mentioning that the screen for the pump is available separately at a fairly reasonable price.  If you don't have an in-line filter upstream from the pump then it might be worthwhile investing in a few of these.

Espar provides some very nice information in these two manuals.  The "Basic Repair Analysis" is intended for other similar models but has color photos and good explanations of what caused specific problems.  The other one, "Troubleshooting and Repair Instructions", steps you through the troubleshooting procedure and provides drawings and schematics.  I've got both of these in PDF form on my iPad along with most manuals for all our gear on board.  Another nice one to hold onto is the installation manual that came with the original kit.  This provides a nice electrical diagram with color coding for all the wires.  I've attached all three of these, and more, at the top of this post for anyone who might be interested.