Before leaving on our trip to Florida on Dec 1st, I had my HH tech in Janesville, WI check everything over. I told him about the grinding whining sound when the unit was going through the purge cycle. He told me it was an indication of the control unit going bad.
I didn't want to be on the road for 3 months, and have it go out, so I started looking for a replacement. I searched Aqua Hot website, and others that I found online. The least expensive for a new unit was $757.00, plus shipping. Somehow, searching this site, I found a post from 2009 (which I can't find now) where the BAC member found a new replacement in Brooks, OR at McCoy Freightliner. The price was in the low to mid $500s. I thought, well its 6 years later, but what the heck. I called, talked to Matt Warner in parts 503-463-6303. He said they had none in stock, but he could order it for me from Webasto and then when they get it, ship it to an address of my choosing. The price before shipping was $527.68, and then $40 shipping which included Webasto to them and them to me. Matt said Webasto would not ship direct to me. $567.68 total. I had it shipped to the RV park in Clearwater where we planned to be by December 22nd. It came as scheduled.
The old unit has been really grinding a lot lately, so today I replaced it with the new one. Works perfect!
This forum has saved us thousands of dollars in 4 years. I hope this helps someone save some money.
Stan
Edit: I searched some more and found the post I was referring to. I was a bit off on the price he got. But I'm still a happy camper!
http://beaveramb.org/forum/index.php/topic,130.msg469.html#msg469