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Topic: Puzzling aquahot control issue, second chapter, the double nut. (Read 607 times) previous topic - next topic

Puzzling aquahot control issue, second chapter, the double nut.

About a week ago I posted "Aquahot control issue, Rudy rescued me..."

with the conclusion that the the culprit was the diesel switch in the kitchen.
I obtained a switch, replaced it and the aquahot furnace came on.

I failed to test the switch I took out, I just assumed it was faulty.

Success, so I posted and thought.

Several days later the aquahot system furnace was dead again, although the thermostats called for power.

Then went back and tested the failed switch, and found out it was functional.

Called Rudy again, discussed several options and circled in on a loose supply connection or ground connection.

But where?

Took a flat screwdriver and tightened the red 12 V supply cable terminal again. (Although I had 12 V against ground).

Then decided that might as well check the 12 V green ground cable (see pictures) with the 11mm nut. Nut was torqued, but when I pressed nut against the housing, I could hear something energizing. So I took the nut and two attached cables off, and to my surprise there was a second nut underneath.  This one was loose, and had a connection to the control unit. I torqued the second nut, reattached the two cables and torqued the first nut again.

Everything is running now as it should.

At the first check a week ago I had tightened the nut on the green terminal, but did not realize it only tightened the first nut against  the second on.

Just knowing that my terminal post has two 11 mm nuts might come in handy in trouble shooting. No idea if it was so from the factory.

Regards

Klaus

The world is not interested in the storms you encountered, but whether or not you brought in the ship.
Raul Armesto

2003 U 320 4020 Unit 6145

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #1 –
Awesome find and share, Klaus!!  Keep 'em coming!!!
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #2 –
I noticed in your picture that you have 2 15 amp fuses.
I was working on my aqua hot today and noticed the same thing yet my manual shows all my fuses being 10 A.
I switched my 2 15A to 10A.
Don't know if I did the right thing.
I will check those connections tomorrow
Frank & Daisy
NO LONGER  "looking for the perfect Foretravel
36' or less non slide preferred."  She has been found and is ours.
2003 U320 36' non slide  Unit 6103
Cummins ISM 450
Allison 4000MH

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #3 –
Quote from: kepeters –
to my surprise there was a second nut underneath.  This one was loose, and had a connection to the control unit. I torqued the second nut, reattached the two cables and torqued the first nut again.

Everything is running now as it should.

Regards

Klaus


So on the other side of the second loose nut inside the panel against the head of the bolt is the ground wire for the ac power for the heating element.  I wouldn't imagine it was damaged but if you pull off the little cover plate facing the basement you will find three wire nuts. If you remove and separate the green ground wires you can take your volt ohm meter and check it for a proper ground on the Aquahot side. Missing ac grounds can cause problems. Possibly not today but down the road. Just make sure it's powered down while checking. RV Safety | No~Shock~Zone
Scott

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #4 –
Quote from: Lt403 –
I noticed in your picture that you have 2 15 amp fuses.
In the photo there is a wiring diagram in the upper left.  It shows five 10 amp fuses and fuse "F" (Diesel-Burner) is 15 amp. 

Richard
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
The selected media item is not currently available.

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #5 –
Good observation,

I sure missed that.

To be safe, I will change the one 15A fuse back to 10A as in the wiring diagram.

At some time this winter I am contemplating to post an essay on the forum titled something like :" Lessons learned from buying a technically advanced coach like Foretravel for the first time when you are over 70 years old. "

Do not get me wrong, I am very glad I did buy the coach, and would do it again tomorrow.

 I do not think the essay will contain any deep insight, probably just the musings of an old man, who feels sorry for being beyond his past glory days.

But, I am a member in good standing on this forum, and I am not the only one in this age bracket.

Regards

Klaus

The world is not interested in the storms you encountered, but whether or not you brought in the ship.
Raul Armesto

2003 U 320 4020 Unit 6145

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #6 –
Quote from: kepeters –


At some time this winter I am contemplating to post an essay on the forum titled something like :" Lessons learned from buying a technically advanced coach like Foretravel


My essay would be Foretravel distractions that prevent me from finishing what I what to do or at the least get me sidetracked doing other stuff.
Scott

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #7 –
Richard you are correct the last fuse is 15 A.
I don't know why my manual shows a 10 amp.

I went to the Aquahart website and looked at the manual there for my unit and it also shows the last one on the right to be a 15 amp fuse

The first two pictures are from the Aquahart website the last picture is from the actual manual that I have in my coach
Thanks
Frank & Daisy
NO LONGER  "looking for the perfect Foretravel
36' or less non slide preferred."  She has been found and is ours.
2003 U320 36' non slide  Unit 6103
Cummins ISM 450
Allison 4000MH

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #8 –
That double nut is used fairly commonly by other manufacturers. I had similar issues with my Newells.
Checking for voltage and finding 12+vdc can mislead you to pass over a problem like this. Voltage will pass until you start pulling amps then the voltage can drop below what is needed. Not easy to find these problems but can be caused by loose connections like this, bad wire crimps (been there multiple times), wires corroded inside the insulation (been there too), etc.
For future troubleshooting you can try watching the voltage across a connection like this and see if it drops. If it does drop more than expected there is a problem somewhere between.
Good find! You'll be an expert in no time.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #9 –
More than one of us have had the nut on the ground post get loose and just fall off and then ground cables come off and then what.

It always reminds me to start with the most basic level and work out from there.

Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #10 –
Two of the pictures show a loose wire with a spade connector. One picture the wire is white and and the other picture it is red. I have that same loose wire. What is that wire for?
Alan Fink
Waupun, WI
2000 Blue Bird Wanderlodge  LX40
2018 F150 4x4
2020 Jeep Wrangler Unlimited  Rubicon JL

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #11 –
Alan, If the loose red wire disappears into the harness going to the burner, it is the diode wire.  The diode wire should be connected to the load side pump (bottom) connection of the middle relay.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas
 

Re: Puzzling aquahot control issue, second chapter, the double nut.

Reply #12 –
 The process for finally figuring out what the actual cause was is an example of the principle of Occam's razor:

"From all possible explanations for an occurrence the simplest one is the one with the highest probability"

Regards

Klaus
The world is not interested in the storms you encountered, but whether or not you brought in the ship.
Raul Armesto

2003 U 320 4020 Unit 6145