Originally Posted by msulc
Hi Nick, I have the Nau-t-kol Stone Cold reefer. The manual says it has a 1/4" standard male fitting. It does look like a car tire valve.
Is there an adapter for this or do I need to get a gauge set?
Yes, it's a 1/4" Schrader valve. I always use a gauge set for topping up. Let me give some tips here:
- purge hoses with a little refrigerant
- an empty system: switch system off; open both high side and low side valves; open valve on refrigerant tank; let refrigerant equalize between tank and system; gauges show building pressure; when equalized, close both high and low side valves
- start system; let it run for a couple of minutes and check evaporator plate for frost. The _whole_ plate must be frosted; if not, open the low side (suction side) valve on the gauge set to allow some extra refrigerant into the system; close after 5 secs; test frosting again and repeat until fully frosted.
- as box temperature comes down, so does the pressure inside the system (refrigerant shrinks) and you must add more refrigerant to keep the evaporator fully frosted. Keep at it until the thermostat switches the system off.
- at this point (when compressor starts running again) I add some extra refrigerant so that I see frost on the copper tubing for about a foot of length from the evaporator. This provides some buffer.
- keep in mind that when you sail from tropical to moderate climate you need more refrigerant and vica versa.
So, for filling a Danfoss based system, use the frost on plate and tubing as indicator of charge, not a gauge reading.