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Old 12-23-2019, 10:09 PM   #1
Hotratz
 
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Default Espar/Digimax D1000/cabin heat

Howdy folks,

I believe I have the Digimax D1000 controller installed (done by previous owner). I understand that this unit is not fully compatible with the Westy specific heaters so it only serves as an on/off switch with no thermostat control/low/med/high fan (what else is missing?)

Wondering if there are alternative controllers that are fully compatible or if there are workarounds to have thermostat control? Sure would be nice to restore that functionality.

I don't know if the factory controller failed or if it was simply bypassed to circumvent the need for a trip to the shop to reset heater after three failed starts.

Thanks
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Old 12-23-2019, 10:43 PM   #2
Mr1987joker
 
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Default Re: Espar/Digimax D1000/cabin heat

Yes, that's the Digi Max 1000. I replaced the brain on my original Espar D4S heater when it broke. Rixens Enterprises Inc. in Sandy, Oregon sold one to me. Now you have to change the wires to fit the new Espar wiring harness. Not that hard. My Digi has all the features that it's supposed to have. I can read codes and reset them. The Digi also has several heater settings to maintain the proper heat in the van. When the heater steps down its speed, I can barely hear it. Rixens is great, they actually make all the heat systems in the Winnebago Revel.

Cheers, Brennan
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Old 12-23-2019, 10:50 PM   #3
OldWest
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Default Re: Espar/Digimax D1000/cabin heat

1. Option--Compatible?

OneManVan found there were updates during the production as to whether various controllers were compatible with the specific Espar 4DS.

https://sprinter-source.com/forum/sh...72&postcount=4

https://sprinter-source.com/forum/sh...8&postcount=24

https://sprinter-source.com/forum/sh...1&postcount=25

2. Option--Replace Espar.ECU

https://sprinter-source.com/forum/sh...0&postcount=12

3. Option--Replace Everything

There is a newer Espar heater.

https://sprinter-source.com/forum/sh...ighlight=espar



Please post whatever you find and do. Thanks.
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Old 12-24-2019, 06:05 PM   #4
Hotratz
 
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Default Re: Espar/Digimax D1000/cabin heat

Thanks for the info - helpful.

Wondering if this is something I could throw an arduino at? Any ideas about the codes the controller sends? Digital signals or analog? Proprietary?
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Old 12-24-2019, 09:00 PM   #5
OldWest
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Default Re: Espar/Digimax D1000/cabin heat

From the posts by OneManVan, he figured out how to add a thermostat to make the heater run at medium speed only. If that's what you're asking?

https://sprinter-source.com/forum/sh...6&postcount=22
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Old 12-24-2019, 09:08 PM   #6
Hotratz
 
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Default Re: Espar/Digimax D1000/cabin heat

No doubt the easiest solution and is better than always on/off. Nice to have the additional functionality of fan speed control. Thanks for finding that post!

The Arduino platform is a family of small single board programmable micro-controllers. Sky is practically the limit as to what you can do with them.

Happy Holidays to you.
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Old 12-27-2019, 09:34 PM   #7
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Default Re: Espar/Digimax D1000/cabin heat

Quote:
Originally Posted by Hotratz View Post
Howdy folks,

I believe I have the Digimax D1000 controller installed (done by previous owner). I understand that this unit is not fully compatible with the Westy specific heaters so it only serves as an on/off switch with no thermostat control/low/med/high fan (what else is missing?)

Wondering if there are alternative controllers that are fully compatible or if there are workarounds to have thermostat control? Sure would be nice to restore that functionality.

I don't know if the factory controller failed or if it was simply bypassed to circumvent the need for a trip to the shop to reset heater after three failed starts.

Thanks
The Espar D4S and central electronic controller in my Westy both work correctly. I know that my Espar D4S has the OEM 'brain' in it.

I wanted to add a DigiMax D1000 on the side of the kitchen cabinet so I could control the heater from the bed - IE: turn it on in the morning before getting out of bed to warm the camper up. But mainly I wanted it for the diagnostic capability. So I hard wired everything in and when I tested it the behavior was just like you described. IE: it simply performs as an on/off switch with no thermostatic control.

I think the Central Electronic controller was originally designed to work in the Westfalia California van camper. I don't think it had the Espar D4S heater in it - I think it had something else. Apparently Westfalia 'customized' the firmware in the Espar D4S 'brain' so that it would be compatible with the Central Electronic controller.

Anyway - regardless of the history - you cannot pair an off the shelf Espar controller with the Westy specific D4S 'brain'. Nor can you pair an off the shelf D4S 'brain' with the Westy specific heater controller functionality built into the central electronic controller.

I've performed some voltage and resistance measurements on the control wires using both the D1000 digimax and the westy central electronic controller under various conditions/temperatures.

In a nut shell the way the OEM Espar D4S 'brain' and controller works goes something like this.

1) The yellow wire is call for heat - when 12v is applied that latches a relay in the D4S 'brain' that connects the D4S main power line to 12 volts through a 10 or 12 gauge wire.

2) The grey wire is for actual temperature. IE: it should be connected to a thermistor mounted somewhere in the camper. I believe the D1000 has a thermistor built into it. If no thermistor is connected then the D4S uses a thermistor inside it's 'brain'. Note: that in this case the fan will run continuously while the yellow wire is energized. This is because the system is measuring the temperature of the airstream flowing through the heater. If the airflow stopped then the temperature inside the heater would rise well above the cabin ambient temperature and the heater would not turn on.

3) The grey/red wire is basically the desired temperature. A variable resistor/rheostat rated 1750 to 2180 ohms can be used to select a desired temperature between 48 and 93 degrees.

All that stuff is fairly straight forward and well documented. Where things get weird is when you start to measure the voltages and resistances under various conditions with the Westy specific D4S 'brain' and controller. The yellow wire still works the same way. The control wires not so much. Take the following with a grain of salt but this is what I seem to be observing.

1) The grey/red wire ( desired temp ) always seems to have about 1.8 volts on it - regardless of what temperature you select up at the central electronic controller.

2) The grey wire ( actual temp ) varies between 1.7 and 2.6 volts depending on the delta between the actual cabin temp and the desired temp.

So basically the Westy specific stuff works bass ackward from OEM Espar stuff...

In either case I think the D4S brain looks at the difference between the grey wire and the grey/red wire and if it's a large difference then it kicks into after burner mode. If it's a small difference then it goes into stealth mode. So yes - it's all analog.

I scribbled down some of the actual measurements on the schematic I keep with me and I attached it to this post.
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