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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Eric & Alena + 3 on February 02, 2020, 04:49:29 pm

Title: On A Roll Furnace Issues ... Kind Of...
Post by: Eric & Alena + 3 on February 02, 2020, 04:49:29 pm
My front AC went out on us last year on our way to Destin. We had a local shop Lacy's RV Repair swap out the unit I was able to locate. Due to availability in short notice I was only able to purchase a unit without the exact control center I needed for my older setup. I was on vacation and did not have a ladder to get the 100 pound unit in the roof so I took the easy way out.

The Lacy's Repair technician had the correct control center and proceeded with the install.  I was in the RV half watching as he was replacing the unit. When he was hooking up the furnace controls he created a mini shower of sparks then he looked at me very surprised and said oh "someone must have wired things differently". I asked if he needed help turning off the power before something else happened. He declined.

After he said he was done I asked him to test the heater. What he didn't know FT replaced several parts on the heater and everything was working perfect only months prior to our summer travels.  Well go figure the heater would not come on when he tried. The tec went outside and started "probing around" jumping wires in the time delay delay. After another mini spark display he concluded that the time delay delay was bad and not his doing.

Due to the fact that I had it with this guy and being on vacation I told him to just leave and stop charging me to diagnose the problem he created.  I simply turned off the power at the furnace and said I would deal with it later. Since we are back in the cold season I decided to dig into the problem.

Turns out the tec very clearly wired the control center incorrectly. He had a ground wire hooked up to one of the blue furnace wires and the positive lead from the furnace hooked up to the other blue furnace wire at the control center.  You can image what happened when I turned the power back on at the furnace and then turned the thermostat to furnace.

You guessed it. The control center created a short in the furnace relay and eventually popped the main furnace fuse. However, enough time passed that the control center short stunk up the whole RV with stink burnt electronics smell.

After disconnecting everything and chasing down every wire and connection I found his mistake. The second furnace wire going to the furnace was pinched and cut under the AC when the tec installed it. See the white wire in the picture.

 I was able to get the furnace to work properly when I bypassed the control center. This confirmed my thought that the control center was now fried. Well the smell really gave it away but this proves it. I also used an ohm meeter and check the resistance of the blue furnace connections at the control center. About the same resistance with the furnace on and off at the thermostat.  I can hear the relay clicking but no real change in resistance. The voltage drop across the relay is also around 2.6 volts.

I ordered a new control center and will install it on Tuesday when it comes in. I also plan to call Lacy's Repair and see if they will pay for the new control center.

I will let you know how it all goes.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Old Toolmaker on February 02, 2020, 08:17:01 pm
I was on vacation and did not have a ladder to get the 100 pound unit in the roof so I took the easy way out.




Due to the fact that I had it with this guy and being on vacation I told him to just leave and stop charging me to diagnose the problem he created.

Turns out the tech very clearly wired the control center incorrectly. H

You guessed it. The control center created a short in the furnace relay and eventually popped the main furnace fuse.

After disconnecting everything and chasing down every wire and connection I found his mistake. The second furnace wire going to the furnace was pinched and cut under the AC when the tec installed it. See the white wire in the picture.

I ordered a new control center and will install it on Tuesday when it comes in. I also plan to call Lacy's Repair and see if they will pay for the new control center.

I will let you know how it all goes.

My condolences for your loss.  Maybe in the future you can pay the technician to do the grunt work, whole you do the stuff that requires, how do you say it, thought?

Art.

FWIW Many years ago "we" (The Company) purchased a new Hydromat rotary transfer machine.  And while it was sitting there waiting for the technicians to come Lynn had some down time so started wiring the various boxes together.  It gave him a quiet place to sit (hide) and he could putter along doing something easy.

Once the technician arrived, since Lynn had already made significant progress they talked.  I had the pleasure of telling the older brother (President) that his younger brother (Vice President) had purchased a used machine with 4,000 hours on it.  Amazing what you can learn if you're wearing a company uniform, sitting on a garden cart sorting wires.

Eclipse 12-100 | Hydromat Inc. | Rotary Transfer Precision Machining (https://hydromat.com/machines/eclipse-12-100)
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Eric & Alena + 3 on February 04, 2020, 09:31:52 pm
The new control center came in today. I cut out the many butt connectors and mini extensions the previous technician installed. I soldered and heat shrunk all the new connections. I also added labels to the wires for future reference. The whole job took about half an hour.

Turned everything back on and ran through every mode and zone and all works as it should!

Dometic 3109226.005 Comfort... Amazon.com: Dometic 3109226.005 Comfort Control Center for 630035 Ducted:... (https://www.amazon.com/dp/B003BIXYT2?ref=ppx_pop_mob_ap_share)
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Caflashbob on February 04, 2020, 10:50:50 pm
Soldered wires seem to need being more supported.  My guru buddy says he has fixed many old Marathon Prevost conversions broken soldered wires. 

Surprising to me.  Mechanical crimp connector with support has less of a failure rate according to him.

Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: nitehawk on February 04, 2020, 11:21:37 pm
Didn't know that.
Explains why I had failures until I first slid some shrink tubing up one wire, soldered the connection , then slid the shrink tubing down over the connection and heated the tubing to a tight fit on the connection.
Just this fall I did the taillight conversions with solder and shrink tubing AND "Shoe Goo" to completely stop wires moving and breaking connections.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: MarkC on February 05, 2020, 12:41:19 am
I've been told that's why planes use solderless connectors, the vibrations of a vehicle (even though Ft's ride very smooth) are rough on soldered connections.  In our Off Road race vehicle (Baja 500) all connections are with crimped solderless connections and heat shrink tubing.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Old Toolmaker on February 05, 2020, 08:46:43 am

Turned everything back on and ran through every mode and zone and all works as it should!


Don't that feel great?
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Travelin' Man (RIP) on February 05, 2020, 09:04:54 am
I soldered and heat shrunk all the new connections.

No offense but the heat shrink tubing doesn't  look shrunk enough to be tight on the wire.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Eric & Alena + 3 on February 05, 2020, 09:31:37 am
So personal opinion rant here. I have to disagree with any comment regarding a soldered connection being inferior.  Done properly I have never seen one fail. The soldier and good shrink wrap is gas lighter than any other connection and it will never pull apart and provides better contact area. . Good wire, good solder, and good shrink tubing cannot be beat on wires up to around 12 gauge stranded.

I have used this same method on boats for many many years as well as off-road Jeeps. I managed the electrical repairs at the LSU coastal studies and forestry departments for almost 10 years where I replaced and rewired hundreds of connections on boats being taken out by unqualified graduate students. The late night recoveries die to electrical failures dropped to almost zero once I finished the repairs.

I still get compliments about the quality of repair and lack of issues on those boats still in use today (over 20 years).

In regards to the shrink tubing on these pictures it is shrunk down all the way tight around the wires. The shrink tubing used here is a 3M product with an adhesive that seals tight and usually has a little bit pushed out at the ends. It is just the picture angle that makes it look not all the way sealed.

Don't get me wrong.  Everyone is entitled  to their opinion and nothing is meant to be taken personal (by me or others). We all "hear" stories and maybe even witness a situation that isn't fully understood. This is simply my option that i have a lot of first hand personal experience.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: craneman on February 05, 2020, 09:40:08 am
My stepson is a body shop mechanic and told me the insurance companies require solder connections on all loom repairs and wired components. It came up when I asked him why he just didn't use butt connectors to speed up the jobs.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: wolfe10 on February 05, 2020, 09:52:25 am
I also do a lot of marine wiring.  Particularly on smaller gauge wire, generally soldered.  Never had a failure.  But have also used properly crimped butt connectors (filled with silicone dielectric grease). Never had a failure.

Sure, wires are secure so they don't move around after splices done.

I suspect there may be four, not two levels of quality here:

Properly done solder job.

"Bubba" done solder job.

Properly done crimp connectors.

"Bubba" done crimp connectors.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Chuck & Jeannie on February 05, 2020, 10:03:57 am
Brett:

Add one more (lower) quality connection to your list:  Wires twisted together and wrapped with PVC electrical tape.    >:(
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: wolfe10 on February 05, 2020, 10:12:00 am
Brett:

Add one more (lower) quality connection to your list:  Wires twisted together and wrapped with PVC electrical tape.    >:(

AND, the wire nut.
Title: Re: On A Roll Furnace Issues ... Kind Of...
Post by: Old Toolmaker on February 05, 2020, 02:53:36 pm

Properly done crimp connectors.

"Bubba" done crimp connectors.

The crimping tool and connectors you purchase at NAPA or Lowes give you a "works, sorta" crimp.

If you want a good industrial style crimp you need to spend some serious dish on the tools and consumables, unless of course you have a electronics surplus house in your neighborhood.

R624 0003 Rennsteig Hand Crimp Tool with Case (https://www.waytekwire.com/item/385/Rennsteig-R624-0003-Hand-Crimp-Tool-with-Case-/)

Rennsteig 624 1667 3 0 RT Crimp Die Set for Apex 2.8mm Series | Waytek (https://www.waytekwire.com/item/543/Rennsteig-624-1667-3-0-RT-Crimp-Die-Set-for/)