Eutectic Refrigeration - What to Do ?

[MoonlightSailor]

I don't think he is trying to rip us off but I see your point. I'm having a hard time writing a check for $500 for what he did. He has said he can bring our current system to working well. I don't think he's pressuring us to buy anything.

Why did he remove the R12? Could be one of two reasons or both. We were talking of replacing the refrigerant with a differet type and there is an oil leak at the shaft seal on the compressor.

What is TVX?

As far as I know, there are no high and low pressure switches on the system. It's all manual. I have to turn on the Kubota, let it warm up. Flip the switch on the DC board to activate the clutch and then it starts cycling down. I turn it off when it has reached the desired temp in the box. Does that make sense?

[daddle]

TXV (or TX) Thermal expansion valve. Replaces the capillary tube in fancy systems. Regulates refrigerant flow into the evaporator by sensing the return tube temperature. Usually mounted to a holding plate.

[MoonlightSailor]

I just asked Mr Frost why he evacuated the system and he said it was illegal or against the law to leave rerfrigerant in a system with a known leak.

My dad was present when he added more refrigerant to the system. He said it had to do with the sight glass and it's reading. So therefore, needed more refrigerant.

Can a compressor leak refrigerant from a round the shaft seal?

[Richard Kollmann]

MoonlightSailor, It is interesting how one can use excuses to avoid doing the right thing. A system that needs only three pounds of refrigerant to perform correctly has five pound of refrigerant in it after not running for a period of time does not have much of a leak. Shaft driven refrigerant compressors that set idle for extended times do tend to leak small amounts of refrigerant carrying oil, it is the oil on this type shaft seal that prevent refrigerant from leaking out.. When these compressors are used in trucks and large cars the clutch is engaged frequently even in winter to keep oil on seal plate. Federal EPA regulations and I dough California Regs require refrigerant to be removed if leak can be stopped. My point is that presents of oil dampness is not enough to confirm system was leaking as this type seal will repair itself after running for a few minutes, if leak was do to seal inactivity. If a leak was confirmed at shaft seal with some type of leak detection equipment it could have been isolated by closing both Roto-lock valves on top of compressor. No matter how you interrupt EPA regulations there would be no need to remove refrigerant if long term intensions were to repair leak. These compressor Roto-lock valves were designed to isolate refrigerant in system while compressor being changed or repaired. Sight glass is not a true indication of refrigerant quantity on many engine driven systems unless holding plate is frozen an any experienced boat refrigeration technician should know this.

The quick way to confirming that compressor is functioning properly is by isolating it away from the rest of system closing Roto-locks. Then connecting a servicing gauge set that can be used to duplicate the rest of system. With gauge center port capped and both hand valves open clutch can then be energized to start compressor rotation. Refrigerant then flows through gauge set hoses in a complete loop. All that is needed now is a restriction to simulate an expansion device. By closing blue low pressure hand gauge valve slowly regulating low pressure to around 5 psi compressor can e tested.

If compressor is good then there is a problem with refrigerant flow. There is only one device in this system the Thermo Expansion Valve (TXV) that restricts and controls refrigerant flow. If a system ounce worked OK to the satisfaction of owner forget new systems or modifications in lines or components look for something causing excessive or restricted refrigerant flow. Nine times out of ten it will be a restriction caused by a hand valve partway closed or a plugged inlet screen in TXV or even a faulty TXV. There are only two moving parts in this system compressor and TXV. Another suspect area would be that unidentified device in return line coming out of holding plate it could be causing a flow restriction, this might even account for techs belief system was low on refrigerant.

[MoonlightSailor]

Richard, that black blob looking thing on the low side at the box is a thick black tape used to (I suspect) insulate the temp probe coming from the TXV.