Heat Controller R410A manual Component Considerations for R410a, Compressor, Filter Driers

Table 2. R410a Pressure/Temperature Chart

R410a

Temperature	Pressure
°F	psig
-15	31.3
-5	42.2

120418.0

150612.8

Component Considerations for R410a

Compressor

Wall thickness has increased with the increase of operat- ing pressures of R410a. The internal pressure relief valve setting has been increased from 375-450 psig for R22 to 550-625 psig for R410a. Although the discharge pressure is higher in R410a the discharge temperature should be lower due its higher vapor heat capacity. Desuperheating hot water generators must be designed around this lower hot gas temperatures as well. High pressure switches will now open at 600 psig ±10 psig and reset at 450 ±10 psig. The compressor oil must be polyolester (POE) based. Mineral oils should never be used. POE oils absorb

R410a Application and Service Guide

moisture VERY easily. For this reason any compressor using POE oil should only be exposed to ambient air for short periods of time during manufacture or service. See the service section of this manual for more information.

Condenser/Evaporator Heat Exchangers

The heat exchangers must be designed to have a working pressure above the 600 psig level. In some cases this can mean a thicker wall.

Filter Driers

Liquid filter driers must have working pressure of no less than 600 psig and be approved for use with R410a. A 100% molecular sieve with no activated Alumina is rec- ommended for maximum moisture removal. It is always required to install a new filter drier whenever the system is opened.

Suction line filter driers should only be used after a burn out and should be removed after an appropriate clean-up time.

Thermostatic Expansion Valves

R410a metering devices are about 15% smaller than R22 devices. The selective charge used in the bulb must be matched for R410a operation, therefore a TXV must be designed for R410A use. METERING DEVICES for R22 and R410a are NOT INTERCHANGEABLE.

Refrigerant Tubing

There are no general changes to the tubing other than the working pressure increase to 600 psig. Generally the lower refrigerant flow rate of R410a versus R22 does not result in any pipe diameter changes.

Polyolester Oils

POE oils are VERY hygroscopic. They readily absorb moisture and hold it. For this reason POE oils should be limited in their exposure to ambient air during manufacture or service. The lubricant should be exposed to ambient air for no more than 15 minutes. Always store POE oil in glass or metal containers. Pumps are recom- mended to move the oil from containers to the refrigera- tion system. If the system is under a vacuum, break the vacuum with refrigerant or dry nitrogen. It is never recommended to break the vacuum with air. Liquid line filter driers should be used to remove any moisture in the system. Charging system may also contain a replaceable filter drier for improved moisture removal. In summary:

•POE oil is hygroscopic and will readily absorb moisture

•Never store POE oil in plastic containers. Always use metal or glass

•Use a pump to transfer POE lubricants

•Use an approved POE lubricant. They arenʼt all interchangeable

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