Isotherm BD35 compressor troubleshooting

[GrandWood]

So my fridge is not cooling, I’ve followed a bunch of vids on YouTube, the compressor comes on, fan runs all the time, jumpered the thermostat connections on the controller and compressor runs but no cooling. I don’t have a switch installed, just a fuse in the 12v supply.

Unit seems to be operating fine, just no cooling, the coolant line does get cooler, but not real cold. I purchased one of the recharge kits using a bullet valve to try a recharge, or at least see what the pressure is.

I can hear a gurgling sound in the fridge like the coolants moving through the plate, but is does not get cold or even frost up.

The control/thermostat in the fridge does not seem to shut the compressor off or the fan when I turn it off. It’s kinda a chincy piece. Before I punch holes in the line to try a recharge, is there some way to test the thermostat/temp controller.

Electronic Compressor module seems to be fine from the troubleshooting tests I did that were in the manual and online, but I’m also thinking it could be bad and or the temp control.

 

[GrandWood]

Well I found the problem pretty much by accident. I have a leak at the point where the cold plate fittings join with the compressor unit.

I also found that the thermostat in the box must be turned all the way counterclock wise, and it’s a firm click, so the thermostat is turning the unit on and off.

I had let the unit run for awhile and while down next to it, I had my son shut it off. I could hear a hissing sound, as pressure was leaking off, I moved the copper lines up and down where they join and the hissing came and went, then nothing. So I doubt there’s any Freon in the lines.

Guess I’m going to have to get a gauge set and learn how to use um, as trying to find a mechanic for any type of repair has been a joke. Here in Poulsbo, Wa, even up in Port Townsend, ya can’t find anyone to do anything. Reefer techs are almost non exisistant.

 

[Turtle Blues]

I erased a long response. Search for Richard Kollman's write ups on Cruisers forum for diagnostics. He was the Guru. Proper power delivery voltage is always the first verification.
You are right to hold off on installing the cheap piercing valve, it will be the source of future leaks.
The connections you refer to are they flare or brazed? If line repair is required it is a good time to install quality service ports.
The sound of pressure equalization on compressor shut down is not unusual, but impossible to diagnose from a keyboard. Any visible gas release?

 

[GrandWood]

The connections are the factory ones were the unit comes precharged. I’m looking into the parts to place a flared tee on the high and low pressure lines and recharge the system myself as I can’t find anyone to even come and look at it. I will cut out those connections and flare the lines myself. The hissing I heard, I was able to move the lines up and down at the connectors and stop the hiss and open it again. I doubt very much there’s any coolant in the system. It works as it should but does not cool even the slightest bit. Thank you for your input, much appreciated

 

[Turtle Blues]

My 2c is braze on a couple of quality schraders if possible when you effect your repairs. But that's because i have the torch and the nitrogen. If you flare there a couple of good quality sealants rated for this application. They will probably do just fine. Gauges are not expensive real pain is you need to pull a good 30" vac on the system but even vac pumps are plentiful on Amazon

 

[GrandWood]

My 2c is braze on a couple of quality schraders if possible when you effect your repairs. But that's because i have the torch and the nitrogen. If you flare there a couple of good quality sealants rated for this application. They will probably do just fine. Gauges are not expensive real pain is you need to pull a good 30" vac on the system but even vac pumps are plentiful on Amazon

I was thinking there should be a connection to the Tee for a shrader valve install.

 

[GrandWood]

hopefully there is some sort of adapter to the tee for a shrader valve

 

[Turtle Blues]

Yes, Believe Schrader to female flare exists. Get a good flaring tool too. My bench success rate on small tube is not what I would brag about and trying to do it in place is tougher yet.