OT - Electrical properties of R-22

Does anyone know if R-22 conducts electricity? I want to use a switch line this: http://www.mcmaster.com/#liquid-level-switches/=scj5ru to monitor the level of refrigerant in the receiver.

If not, can anyone recommend a suitable switch? I have no ports on the side of the receiver, but I do have a pipe connecting the bottom and top of the receiver that has sight-glasses in it. I was going to install tees between the sight glasses and the pipe, inserting the switches into the side run of the tees.

HCF₂Cl . I seriously doubt it conducts.

Why do you you want to measure quantity in a receiver? What is the application? I've never encountered the need in a conventional refrigeration system as you can generally tell where your refrigerant is (and even its temperatures) by measuring pressures. Since the thermodynamic properties of R22 are well understood, monitoring compressor suction pressure is one way to know how much liquid refrigerant is in the condenser and receiver.

I suppose that if you want a switch point in the receiver then a thermocouple might work. I use thermocouples as reliable level switches in liquid nitrogen and liquid argon tanks. Use a metal sheathed T/C and either put it in a thermowell or feed it through a compression fitting. A thermowell will slow down response but you can change it without venting the system to atmosphere. Direct immersion through a compression fitting will give you faster response but less serviceability.

Like most refrigerants, it does not conduct, if it did, hermetic refrigerant compressor would have trouble getting the leads insulated inside the shell as they typically use a Fusite.

I have used one that looks like 4909K63 in this application, it's actually a brand that Dwyer bought out a years ago (WE Anderson).

Be sure to check material compatibility of all wetted materials, refrigerants can swell many elastomers. On R22, some neoprenes are OK as are teflon, nylon, etc. Use Viton or Buna N and you will have issues.

Just a bit of a pedantic caution - any material will conduct electricity if the voltage is high enough. The perfect example is lightning.

There are level switches that can be mounted in a sight glass - check Omega Engineering for examples.

Tom,

True enough on voltage but I assume the OP will be working with low voltage, at worst case medium voltage so he should be OK. I've plenty of experience on <600V system and conductivity should not be a problem.

R22 is non conductive, however you can measure capacity change with some rods.
and yes a lot of installation use a level controller to control the level in the evaporator, as this is boiling to heavy to have good measurements.
you also could use MSA they have a magnetic float in the sight glass and some reedswitches mounted outside.

Most industrial refrigeration still uses float switches. There are some capacitive level sensors out there but they are sensitive to foaming from compressor oil so I would not recommend them. For float switches I would look to Hansen, but Parker also makes some. Be absolute sure that they are rated for your refrigerant.

We use the same Hansen level probe as OkiePC sugested in the Low/High temp recivers with R-22 as cooling media, works great.