Heater Maintenance

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 (D2 and D4) but it relates well.  It also has nice 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.  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 keep these in PDF form on my iPad along with most manuals for all of our electronic and mechanical gear on board.  I've attached all three of these, and more, at the top of this post for anyone who might be interested.

Besides playing with the heater I also took on a few other items on my long To Do list.

Our mast is rigged so that all the halyards run down through the inside of the mast and exit about ten feet above the deck where they run down to the winches and cleats.  This is a really nifty setup because it prevents the lines from slapping against the mast when the wind blows, a common nuisance in any marina..  The slots where the lines exit the mast have plastic rings called exit plates (see picture) that prevent chafing of the lines.  The exit plate for the genoa halyard broke off about two years ago and I keep forgetting to replace it.  This weekend I got the bosun's chair out and made a proper repair.  The exit plate is held in place with a rivet and of course this piece was still in place so I had to drill that out first.  These are pretty large rivets and the installation required a Herculean effort with the rivet tool while I was dangling in the air.  I eventually managed though so now we don't have to worry about the genoa crashing to the deck in the middle of the next storm.

Another project was the Mainsail preventer (click here).  I had originally installed the eye nuts on the boom with lock washers but over the last few weeks I kept looking at them and decided it would be better to have the base of the eye nuts flat against the boom because of the sideways direction of force when this thing will be in use.  I pictured the stud getting bent because of the gap caused by the lock washer.  It only took a few minutes to make that correction.  At the same time I added a piece of 3/8" hose over the threaded stud inside the boom to prevent chafing of the out-haul and topping lift lines.  With that done I put the end cap back on the boom and called that part of the project complete.

The folks on the boat next to us asked if that's all I do is work.  I told them that this stuff was more like "play" and the stuff I do during the week is "work".  Never-the-less, I did manage to break away from the "play" and get out and do some fun stuff.  On Sunday morning Cheri and I joined about ten other folks in kayaks exploring Tracy's Creek with a very knowledgeable Naturalist for a guide.  The weather was perfect, clear skies and temps in the low 70's.  The picture above shows the location of the creek with our marina in the bottom of the circled off area.  Our guide pointed out all kinds of plants and critters including some dead fish laying on the creek bank that otters had set out to mark their territory.  Pretty cool! This section of the creek was way back there and is surrounded by woods and wetlands with no signs of civilization.  It's practically in our back yard and I never realized it was so nice back there.  We'll hafta get out there more often, fer sure!