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Nice job Lonne-We were just in Winchester bay last week and visited Coos Bay (Vinnies, for BBQ lunch).

I haven't checked w/JC on the wire size for their 12v unit, I'm guessing existing wiring to the back of the Norcold refrig is 12ga. Do you think 12ga would be sufficient to handle the start-up of the compressor? Using your power measurements, you would have 50+amps DC starting current and about 8 amps DC running. 

I like your control scenario using the propane circuit as a surrogate to control 12V to the compressor. To solve the hysteresis issue, one idea might be to use a 5 minute time-delay relay on the compressor start circuit. That way you would not have the compressor try to start against high head pressure.

The wife likes the idea of keeping the existing fridge but with the 12vdc compressor upgrade, now I'm concerned about the wire size for the 12vdc compressor. Its always something!
Hello BAC Members,

I am posting this message for one of our BAC members, Sharon Calderwood, who is not a member of the Forum.  Unfortunately, she lost her husband, Doug, in July as was posted earlier on the Forum. They both drove the Beaver, were very proud owners of their Contessa and gave them many years of enjoyment.  However, she is now wanting to sell their Beaver and possibly downsize to a smaller motorhome.

The Contessa has no slides and length is 36'.  Sharon lives in Vancouver, BC, Canada, however, the coach is stored in Langley, BC by the US border.

If you are interested and would like more information on the coach or see pictures, please give Sharon a call on her cell phone:  604-250-4570 or email her: 

Thank you for your time,

Anita Johnson 
Membership Director

Hi Steve, I have reviewed that schematic, but alas, my 1999 Contessa is not wired at all similar    :-\

I have run a couple of wires to the coil labeled "Exhaust Relay" and monitored it by a meter while driving the coach, but it does not activate under any condition whether I have the exhaust brake switch on or not.  Setting the exhaust brake switch ON does activate the transmission downshifting when I brake, so at least that part of the system is working.  Tomorrow, weather permitting, I will climb under the back of the coach and trace the air line from the exhaust brake to locate the actuating solenoid, and from there start tracing the wire that goes to the solenoid to see if I can discover where they hid the relay that is controlled by the ECU.  Wish me luck.
Hi Bill Lampkin, yes, I would do the 12Vdc option not only because of not having to unsolder and rework the current sense transformer and then resolder it into the board along with a surface mouint resistor, but also because the 12Vdc compressor is also a more efficient compressor (it uses a brushless DC motor and BLDC motor controller). When combined with not having to run it on an inverter, you are able to get the same cooling while saving another ~30W or so.  I do not like how JC-Refrigeration recommends hooking up the 12Vdc unit (they have (in my opinion) a bizarre configuration where they apply 12Vdc to the 120VAC input terminals on the power control board, and then hook the compressor to the heater element terminals.  Then they recommend breaking the warning buzzer off of the fridge's operator panel, and ignoring the heater fault or sensor fault messages the operator panel will give when operating the compressor. 

If I were to do this again, I would use the 12Vdc unit and deliver power to it via a 12V relay driven from the gas valve solenoid output of the control board.  Then I would set the fridge's control panel to "gas" (not "Auto" and not "AC").   The control board (AKA "power board") will activate the gas solenoid terminals when the temperature has climbed to the set value, and also send pulses to the high voltage ignitor coil to try and light the propane burner.  The control board will then check to see if the propane flame has successfully remained lit (if it does not detect the flame it will de-activate the gas solenoid  terminals and try the sequence again).  The flame is detected by sensing if current can be made to flow one way through the ionized gas of the flame, but not the other (this phenomenon is known as "flame rectification" and is used in gas burner appliances like home furnaces as well as in RV gas refrigerators).  To simulate the presence of a flame, I believe I could use the diode and resistor network I have shown.  I would also use a neon lamp like an NE-2 as a spark gap to protect the diodes from overvoltage.  I would use a couple of 1N4007 diodes in series with a 6 MegOhm resistor as my starting value, and alter the resistance via experimentation if the power board was not happy with the "simulated flame". 

My refrigerator is the 4-door Norcold 1200 with ice-maker.  I pulled the fridge out of the cabinetry and layed it face down on the floor of the motorhome to do the conversion.  The videos provided by JC-Refrigeration are a good overview of the labor involved (and yes, it is a two person job to lift and remove the old vapor absorption cooling unit).  Before re-installing the converted fridge back into the cabinetry, I lined the cabinets with EPS foam to make the fridge even more efficient (because afterall, you can't have too much insulation).  I also re-used one of the Norcold factory installed cooling fans as an additional fan to cool the freon coompressor (because you can't have too much cooling or heat-sinking either).  I also bought a roll of aluminum tape and re-coated the whole back of the fridge and much of the sides.  (See the attached pics.)  I also added foam tape wrapped around the cold return line to prevent condensation from forming and dripping down and wetting the back of the cabinet (we live in Coos Bay on the southern Oregon coast, and it is very humid here).

Technical Support / Refrigerator burned my hand
« Last post by Bill Lampkin on September 21, 2019, 09:55:30 PM »
Norcold refrig experts: I touched the button in the photo and burned my hand. What is the function (other than testing my reaction time) to the silver buttons and corresponding plungers (which are also hot). Photo is of left inside door.
If this heating thing is to dew-proof the door, why isn't there a set of contacts on the right-hand door?
Technical Support / Re: Onan won't start Code 19 -- GOVERNOR ISSUE
« Last post by Tom Chace on September 21, 2019, 08:09:00 PM »
Hi everyone

The mechanic just left

The code 19 is a bad governor after checking with a few meters.

My latest question is: Does anyone have any experience or suggestions on swapping the governor?
There are a few tricks that I was told about but the concern is the spring at the bottom of the rotor that connects to the injector pump might be tricky.

Any thoughts and suggestions would be greatly appreciated.

HDKAJ 7.5 KW Onan from 1999
1999 Beaver Monterey 3126-b

Thank You all!

Tom Chace
Technical Support / Re: Removing cabinet
« Last post by Steve Huber Co-Admin on September 21, 2019, 08:02:00 PM »
Unfortunately my coach is at a repair facility getting my last $ worth out of an expiring warrantee policy. If the center console is anything like the one in my 00 Marquis, it is very difficult to  remove as it had the weight of the dash on it. Post a pix or 2 and maybe one of us can see a way to access the exchanger w/o a cabinet removal. If you haven't yet, clamp the hose to prevent more leakage.
Technical Support / Re: Removing cabinet
« Last post by Keith Moffett on September 21, 2019, 07:50:29 PM »
Unfortunately the darn thing is leaking from inside the case someplace.  The fans work fine.
There is a thread about a difficult screw over the accelerator pedal but not on this one.  I hate to start without a good plan first.
Lonne, Always thinking! So, the 12vdc compressor option would be your choice if you were to do again, but you would still need the parallel resistor and relay for the hysteresis issue, right? Other than not having to modify the control board for current sensing, what other advantages do you see for using the 12vdc compressor? Lower power consumption as you don't have inverter efficiency and standby losses? Is your refrig a two door model, or the larger 4 door Norcold? The fins on our 4 door Norcold frost up, but I don't know if that lowers the cooling of the fridg, as ours works well. This summer we ran from the searing heat of California's Northern Sacramento Valley (Oroville) to the cool coast of Wash and Or. It did hit 90 one day, otherwise temps were around 60-65F.

So the wife wants to keep the deep pot drawers under our 4 door fridge. Replacing the Norcold with a residential fridge would require the removal of the pot drawers. So you say go with the 12vdc conversion over the residential replacement??

Thanks again!
To answer your questions:  Yes, I used the 120vac unit from JC-refrigeration; The defroster fans do not take up significant space, and they really do work (even before the conversion I was considering installing something similar to deal with the frost-on-the-fins issues I have always experienced with RV refrigerators); the compressor is very quiet (much more quiet than a home refrigerator), but the defrost fans do make a bit of noise;  I installed a separate 1000W true sinewave inverter in the battery compartment and then ran romex and an outlet to the fridge compartment (I leave the inverter on all the time so it is like an uninterruptable power supply for the fridge); I have measured the power consumption with an inline wattmeter, and the compressor draws 700W for a few seconds when starting, then drops to less than 100W. 

Because the control board is designed to control a vapor absorption system, it does not have appropriate temperature hysteresis (it tries to regulate the temperature to just a one degree delta on the thermister on the fins).  This can lead to the control board trying to turn the compressor back on too soon after it has just been running (freon compressors should have at least 3 minutes rest after running to allow the pressure to equalize on the high and low pressure sides).  To address this, I added a relay to parallel a 390K resistor across the temperature sense thermistor whenever the compressor is running.  This effectively puts a 4 degree temperature hysteresis into the temperature control loop.

If I were to do this again, I would use JC-refrigeration's 12V DC compressor, and use a circuit I have devised to run the fridge in "propane" mode and have the control board think it is running a propane burner.  (See attached picture.)  This way I would not have to modify the power control board.  The circuitry attached to the spark coil fools the control board into "thinking" it has a successfully lit propane flame and is detecting the "flame rectification" phenomenom.
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