HFC Retrofit guidelines


	HFC Retrofit guidelines

Retrofit to an HFC

Note: These guidelines are typical for hermetic and the majority of semi-hermetic systems. Open compressors and some semi-hermetic units may require gasket, seal and/or o-ring replacements. Contact the equipment manufacturer if in doubt.

Step 1

If equipment is still operational, record initial baseline data for later comparison. This would consists of the following:

	System operating temperatures and pressures
	Voltages and running amperages
	Superheat and sub-cooling net temperatures
	Ambient temperatures and humidity.
	Estimated % load condition

Step 2

If the existing lubricant is not POE (polyol ester) or is unknown, drain as much as is physically practical or possible from the system. Measure and note the amount removed from the system. Replace this amount with an equivalent amount of POE.

Step 3

Change out the filter/driers with components approved for HFC refrigerants and POE oil. Also, examine any existing components in the sealed system which may have o-rings or gaskets which may not be compatible. A common one is the liquid line sight glass. Change out components if required and if possible before refrigerant pull.

Step 4

Allow the system to operate for a minimum of 48 hours and perform an additional oil change and filter/drier replacement. The goal is to achieve at least a 95% base of POE lubricant in the system. For most small to medium systems a single oil change will suffice. Larger systems will require 1 or 2 more changes. Test kits are available, but if in doubt, perform two to three oil changes on larger systems.

Step 5

Recover CFC or HCFC refrigerant from the system and weigh the amount removed.

Step 6

Evacuate system to 500 microns. Ensure that the system is free of leaks.

Step 7

Charge the system with 75% of original refrigerant charge by weight. Remember to charge liquid only from the cylinder.

Step 8

Start up the system and allow time for conditions to stabilize. Record operating conditions and compare to original baseline recordings if possible. Adjust charge as required up to approximately 90% or the original charge. Do not overcharge the system.

Step 9

Make sure to label all system components with the new refrigerant and total charge.

Typically, HFC refrigerants will operate at approximately the same suction pressure and a slightly higher discharge pressure at comparable saturation temperatures. Check the pressure/temperature charts for the refrigerant you are using and replaceing.