I installed an Isotherm Compact "2501" U200X000R11111AB along with a SBD00154XA 2 meter extension line set in my Tartan 33R about 2 months ago. It was keeping the icebox at ~40°F with the compressor cycling on and off as expected. If I put ice in the O evaporator, it would stay frozen. I have the thermostat sensing element attached to the O evaporator. And July and August were quite hot here in southeastern Wisconsin. About a week ago I noticed that the ice was melting and the icebox temperature had risen to 46°F. The compressor appeared to be running continuously. The air and water temperature are both about 70°F right now. After talking to Isotherm it was decided that my R-134a refrigerant charge was probably low.
I have purchased a 12 ounce can of R-134a (no sealant) with self sealing valve, not the older piercing style. The system only has a low side service port on the BD50, so I also purchased a cheap hose/gauge set up from Amazon: Amazon.com. The problem is that the service port is apparently what's called a 1/4" flare. The thread diameter is 11mm (7/16"). It does have a schrader valve in it. The hose/gauge has a quick connect fitting. I quicky discovered that the quick connect was not compatible with the 1/4" flare.
Then I purchased this: Amazon.com. The low side adapter threaded on, but I couldn't get the quick connect pushed on far enough to latch on. The quick connect latched onto the adapter just fine prior to being acrewed on to the 1/4" flare. I assumed that the schrader valve in the adapter would release the schrader valve in the 1/4" flare, but it seems to be bottoming out before the quick connect is on far enough to latch. Maybe you can't stack schrader valves. I think if I removed the schrader valve from the 1/4" flare it would probably work, but that would require opening the system up. I didn't want to do that right now.
The next step was to purchase a gauge/hose that had a 1/4" flare connection. Amazon.com This one seems to do it all. I was able to connect it to the can of R134a and the 1/4" flare service port.
I added refrigerant with the compressor running until I got 10 PSI on the gauge. The pressure goes up to 30-35 PSI when the compressor is off. That has restored the cooling and the compressor is cycling on/off as expected. The icebox is still at ~45°F, but with the thermostat sensor on the evaporator, it will take a while to cool the icebox contents down to ~40°F.
Isotherm tech support doesn't know anything about pressures, they only want to talk about a weighed charge. That would be 80 grams in my case. I don't currently have a vacuum pump, but will probably revisit this next boating season. I have a digital scale, but I don't see how you can get an accurate measurement with the hoses and fiddling with the valve on the can.
Any thoughts or suggestions on this will be appreciated.
I have purchased a 12 ounce can of R-134a (no sealant) with self sealing valve, not the older piercing style. The system only has a low side service port on the BD50, so I also purchased a cheap hose/gauge set up from Amazon: Amazon.com. The problem is that the service port is apparently what's called a 1/4" flare. The thread diameter is 11mm (7/16"). It does have a schrader valve in it. The hose/gauge has a quick connect fitting. I quicky discovered that the quick connect was not compatible with the 1/4" flare.
Then I purchased this: Amazon.com. The low side adapter threaded on, but I couldn't get the quick connect pushed on far enough to latch on. The quick connect latched onto the adapter just fine prior to being acrewed on to the 1/4" flare. I assumed that the schrader valve in the adapter would release the schrader valve in the 1/4" flare, but it seems to be bottoming out before the quick connect is on far enough to latch. Maybe you can't stack schrader valves. I think if I removed the schrader valve from the 1/4" flare it would probably work, but that would require opening the system up. I didn't want to do that right now.
The next step was to purchase a gauge/hose that had a 1/4" flare connection. Amazon.com This one seems to do it all. I was able to connect it to the can of R134a and the 1/4" flare service port.
I added refrigerant with the compressor running until I got 10 PSI on the gauge. The pressure goes up to 30-35 PSI when the compressor is off. That has restored the cooling and the compressor is cycling on/off as expected. The icebox is still at ~45°F, but with the thermostat sensor on the evaporator, it will take a while to cool the icebox contents down to ~40°F.
Isotherm tech support doesn't know anything about pressures, they only want to talk about a weighed charge. That would be 80 grams in my case. I don't currently have a vacuum pump, but will probably revisit this next boating season. I have a digital scale, but I don't see how you can get an accurate measurement with the hoses and fiddling with the valve on the can.
Any thoughts or suggestions on this will be appreciated.
