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Aqua-Hot Control Box 4Th Generation Model # WPE-300-901 Operation

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There have been 4 generations of Aqua-Hot Control Boxes. 1st generation is the Silver Metal Case Box, 2nd generation is the Black Plastic Control Box, 3rd generation was the smaller rectangle control box with pigtails for connections model # WPE-300-900 which was a failure from the Aqua-Hot company in Colorado so they came out with the now 4th generation model # WPE-300-901.

My question is specifically regarding the operation of the 4th generation control box, model # WPE-300-901 versus the older 1st & 2nd generation control boxes.

My Aqua-Hot model 100-04 in my Dynasty has a generation 1, silver metal control box, currently running with no problems. I purchased a new 4th generation control box, model #WPE-300-901, to have as a backup just in case.

I have "heard' that when using the diesel Webasto burner to heat the boiler fluid with these new control boxes, once the boiler fluid reaches temperature, the indicator light will turn off on the Diesel Switch unlike how it operates with the older generation boxes where the indicator light stays on ALL the time and only goes off when the system goes into default mode.

Can anyone on here confirm or deny this claim?

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Don't have an answer for you, but hopefully you'll never need to find out!

I was speaking to a mobile RV tech working on a rig next to me this spring, and he swears the gen 1 box was bulletproof!

I told him I was leaving my front cover off to reduce heat buildup on my control box, and he claimed with my gen 1 box, no need!

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Here is the quote from Hydronic Heating Warehouse:

Operation of "Diesel" light inside coach is different than the older boxes.  On heating systems with an electronic board the switch light illuminates when burner is operation.

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Thank you for your post and answer.

That means to me that those coach owners who have earlier versions of the Aqua-Hot systems, such as models 100-01, 100-02 and 431/12 which do NOT have an electronic board, the diesel light switch should be ON all the time unless there is a fault in the diesel system.

Whereas, those that own the 100-03, 100-04, 400 and 600 series which do have an electronic board, the diesel light will go OFF when the Webasto turns off but will come back on when the Webasto fires back up again.

So I guess with systems that have the electronic board, the only way to tell there is a diesel fault is to look at the electronic board to see what fault lights are on. You can no longer just glance over at the diesel Aqua-Hot light to see whether it is lit up or not. What a royal PITA!

I can only surmise that some book educated engineer who doesn't own an RV with an Aqua-Hot system came up with this lame-brain idea and was paid hundreds of thousands of dollars plus a patent to design such a system. EOR!

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The light stays on at the end of the cool down period unless you turn the switch off or it detected a problem. This latest box is really sensitive ver the older versions.  Number one problem it will shut down for low voltage at 1.2 volts high

er then the green LED board and about 2 volts before the old boxes.

(1) the light has a delay when you first turn the switch on while its running about 7 different tests. Than another 2 or 3 secs before it turns on motor while its doing 2 more tests.

(2) Unlike the older boxes on error the light doesn't go out until it completes the cool down 2 minute period. 

(3) One good thing about them is they will mask a problem with your LED electronic control board for about a year.

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