View Full Version : Espar D5W S Hydronic controller question

01-08-2015, 05:50 PM
Hello All, Happy New Year!

I am trying to complete connecting up a Espar Hydronic D5W S. The prior owner had started it but not yet completed it. Unfortunately, I don't have the documentation for the controller board (pics attached). It looks almost complete. The wiring from the Espar to controller is connected. It appears that only the fuel pump and battery need to be connected. The Espar documentation indicates brown and green from the D5W go to the fuel pump. The brown and green on the control board are connectors labeled "MP" (Maybe Motor Pump?)

There is no external controller/thermostat for the unit. The controller has 10 connections for 2 zones (white connectors near top of pic). I am hoping I don't need a zone thermostat and that I can hook up the fuel pump and battery and away we go...

I have an Espar AirTronic heater and it does indeed have an external thermostat. I know that when I turn the air heater off, the unit goes through a cooling off cycle. You definitely shouldn't turn the battery power off prior to letting the unit go through the cooling cycle. Is that the same for the Hydronic? If so, I will have to make some connection to a Zone 1 pin to control on/off while leaving battery power on to the D5WS.

Any input would be appreciated.

http://www.marineengine.com/boat-forum/attachment.php?attachmentid=10496&d=1420755937&thumb=1 (http://www.marineengine.com/boat-forum/attachment.php?attachmentid=10496&d=1420755937)http://www.marineengine.com/boat-forum/attachment.php?attachmentid=10497&d=1420755939&thumb=1 (http://www.marineengine.com/boat-forum/attachment.php?attachmentid=10497&d=1420755939)

Brian silk
01-08-2015, 08:16 PM
Yes right guy.
This is Boat Electric's own control board.

MP stands for metering pump-espar fuel metering pump

All you need to get the heater going should be main 12v POS. and NEG., fuel metering pump, and apply 12v+ to whatever goes to the yellow wire on the heater side of the square/ oval plug that seperates the heater from the control board. I assume your unit has an internal water pump. If it has an external pump then it must be connected or the heater will not start. If you need any more assistance I can try to find the schematics, but it will take alot of digging through piles of old paperwork in boxes, so I hope this gets you going! Let me know how you make out.

Brian silk
01-08-2015, 08:17 PM
Oh , when the yellow wire is de-energised, the heater will automatically go into cooldown.

01-13-2015, 12:19 PM
Thanks Brian. That's just what I was looking for! I shouldn't need the schematic now (although for completeness I wouldn't mind having it).

So, it sounds like an acceptable wiring would be breaker to battery connection on the controller board and a heater on/off switch (SPST) to the yellow wire. When the heater switch is on, the yellow wire is energized +12V and not energized when off. Applying battery power to the controller board when the yellow wire is not energized leaves the controller in standby mode, ready to power up. Like you said, after the heater is on, powering off the yellow wire tells the heater to go into controlled shut down sequence.

Now, just a couple more easy questions.

When the heater is on, it is totally self contained. There is an internal thermostat controlling when it is heating or not, right? Is there any control of that thermostat or is it fixed?

I read the fluid that goes in the unit should be 1/2 anti-freeze & 1/2 water. I assume any anti-freeze will do?

The Espar Airtronic that I have draws about 8-9 amps when starting up. I assume that is standard when the glow plug is being heated. I also assume the Hydronic will draw approximately the same.

Thanks again!

- Dave

Brian silk
01-13-2015, 01:24 PM
Yes. It is automatically trying to keep the coolant at 180 odd degrees F. There is no way to control the water temp sensor.
50/50 long life antifreeze.

Yes, your hydronic will be the same. Cheers