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Author Topic: Hydro Hot problem  (Read 819 times)

Tom Webber

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Hydro Hot problem
« on: January 11, 2019, 04:30:09 AM »
I have a Hydro hot 200 model in a 2006 Monterey.  I believe this is the original unit to the coach. Several days ago the diesel burner light inside the coach would not stay lit. I ordered a rebuilt silver control module and swapped it for the old one. Everything worked fine for several hours, diesel burner light stayed lit and heat was produced. But within five hours the diesel burner light was out. Now I have a new black control box and the diesel light stays lit but the pumps for the two heat circuits will not stay running.  Today they ran for about six hours and I have no idea why they started or stopped. The diesel kicks on and off when hot water is used but no heat. Anyone have an idea as to what is causing the pumps to not run when the thermostats are requesting heat.
06 Monterey
CAT 350HP C9

Fred Cook

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Re: Hydro Hot problem
« Reply #1 on: January 11, 2019, 01:02:07 PM »
May be a bad controller board... had to replace mine last year. Call hydro hot in Oregon and they will walk you through some trouble shooting steps.
Fred & Cindy
2002 Beaver Patriot Thunder 455 CAT
40 FT, 2 Slides, Towing 2012 Mazda III
South Central Missouri, US Army Retired

Jeff Prupis

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Re: Hydro Hot problem
« Reply #2 on: January 11, 2019, 01:45:16 PM »
They're in CO.  800-685-4298       http://www.aquahot.com
The 1st quest they will ask is when did you last have it serviced. If more that 1 year they will not even talk to you. May be thermostat, we had similar issues and that was the solution. Good luck
La Dolce Vita
'05 Beaver Monterey Ventura II
CAT C9 400HP
'06 Jeep Liberty

Gerald Farris

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Re: Hydro Hot problem
« Reply #3 on: January 11, 2019, 03:20:11 PM »
Tom,
First, do you have 12 volts at the circulation pumps when the thermostats are calling for heat? If the answer is no, you need to troubleshoot your control board and/or thermostat. However, if the answer is yes, you either have a ground issue, a stuck check valve, or a defective pump.

AquaHot used a lot of magnetic drive pumps around the time that your coach was built and the magnetic drive coupling between the motor and the pump impeller is very prone to failure. If this coupling fails, the pump motor will be running but it is not turning the impeller, so a new pump is needed.

Gerald
2002 Solitaire (2017 -  )
2000 Marquis, C12 (2004 - 2017)
1993 Patriot  (2000-2004)

Fred Cook

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Re: Hydro Hot problem
« Reply #4 on: January 11, 2019, 10:37:13 PM »
They're in CO.  800-685-4298       http://www.aquahot.com
The 1st quest they will ask is when did you last have it serviced. If more that 1 year they will not even talk to you. May be thermostat, we had similar issues and that was the solution. Good luck

Ok, my bad Colorado it is. I was a new owner and could not tell them when it was serviced last. They talked to me anyway and as I stated earlier, walked me through some trouble shooting. Couldn’t fix the problem so I had it serviced to what came to nearly $1800 that included the board, burner, circulation pump, and other items.  Working well so far.
Fred & Cindy
2002 Beaver Patriot Thunder 455 CAT
40 FT, 2 Slides, Towing 2012 Mazda III
South Central Missouri, US Army Retired

Tom Webber

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Re: Hydro Hot problem
« Reply #5 on: January 12, 2019, 02:42:16 AM »
Good News the Hydro Hot is working. Turns out there was a leak in a hot water lines at the rear of the unit so it could not keep the temp up. As I understand these units provide hot water before moving on to providing heat. Also, a bad radiator cap on the tank which was not allowing the tank and overflow or expansion tank to work together. The unit had been serviced (change filter and nozzle)a month before.
06 Monterey
CAT 350HP C9

Bill Sprague

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Re: Hydro Hot problem
« Reply #6 on: January 12, 2019, 02:04:24 PM »
Two excellent resources were essential in keeping our HydroHot running for a dozen years. 

John Carrillo:  https://heatmyrv.com/

Roger Berke:  http://www.rvhydronicheaterrepair.com/
Bill Sprague
Past Region 1 VP
2019 Tiffin Wayfarer 24TW
Past 3 year owner '15 PleasureWay Pursuit
Past 12 year owner of '04 Monterey w/Cummins ISC 350
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Tom Webber

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Re: Hydro Hot problem
« Reply #7 on: January 13, 2019, 03:06:48 AM »
I purchased a rebuilt silver controller from Roger Berke and had it installed by certified hydro hot technician and it lasted twenty minutes and I replaced it with a brand new black controller that has not stopped yet. I hope Roger will refund my money but at least send me one that lasts longer than twenty minutes.
06 Monterey
CAT 350HP C9

Bill Sprague

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Re: Hydro Hot problem
« Reply #8 on: January 13, 2019, 04:29:45 AM »
Which controller comes in black and silver colors?  I'm confused. 
Bill Sprague
Past Region 1 VP
2019 Tiffin Wayfarer 24TW
Past 3 year owner '15 PleasureWay Pursuit
Past 12 year owner of '04 Monterey w/Cummins ISC 350

Tom Webber

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Re: Hydro Hot problem
« Reply #9 on: January 14, 2019, 03:11:29 AM »
On the side of the diesel boiler there is a control box (module) The old style were silver and could be rebuilt, the new style are black and can not be rebuilt. Both silver and black units are about 4"/5"/1".  The box has two electrical connections on the bottom. Each connection is a different size so they can not be confused
06 Monterey
CAT 350HP C9

Bill Sprague

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Re: Hydro Hot problem
« Reply #10 on: January 14, 2019, 03:40:27 AM »
Tom,

Now I know which one you mean.  Mine was the metal color and was made in Germany.  It had tiny mechanical relays inside! 

Mine worked perfectly for a couple years.  Someone, maybe at the factory, put it in the clips upside down.   One day a fitting in the back started leaking and the compartment filled with a water mist.  I didn't catch it for a couple days.  With the box upside down, water got in it and the relays got "sticky".

At the time, the German price was $900 for a replacement.  Maybe the "black" ones are cheaper.  That was the day I decided that I was not sure I liked having to maintain a HydroHot.  It was a love/hate relationship for about another 10 years!

Before it was over, it was that brain box, two burner tubes, three stir pumps, a burner bearing, one electric element, one electric element relay, one over temp switch, one mixing valve, two rebuilds of the plastic plumbing in the back, eight or ten nozzles, as many filters, a couple boiler caps and a fluid level switch.  The zone pumps, fuel pump and circuit board never failed.  A few of the screws in the connectors holding the wires worked loose a couple times.

We stayed warm and most of the showers were hot! 

« Last Edit: January 14, 2019, 03:55:17 AM by Bill Sprague »
Bill Sprague
Past Region 1 VP
2019 Tiffin Wayfarer 24TW
Past 3 year owner '15 PleasureWay Pursuit
Past 12 year owner of '04 Monterey w/Cummins ISC 350

Stan Simpson

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Re: Hydro Hot problem
« Reply #11 on: January 16, 2019, 05:09:06 PM »
If you guys are talking about the Webasto control unit, here is some information on a new one that is less expensive than buying it from Aqua Hot or the two sources listed above. I replaced it 4 years ago. Its plug and play, and has been flawless. Knock wood.

McCoy Freightliner
Brooks Division
4060 Interstate Place NE
Brooks OR 97303
503-463-6303
$527.68 plus $40 shipping to Illinois

Way less than the $800 plus from others. Pic 1 - old one. Pic 2 - new one.

Stan Simpson & Becky Glover & Moe the cat
2005 Monterey Laguna IV
C9 400 Cat
Honda CRV toad