279550-YIM-A-0207
Unitary Products Group
15
Compressors
The scroll compressor used in this product is specifically
designed to operate with R-410A Refrigerant and cannot be
interchanged.
The compressor also uses a polyolester (POE oil), Mobil 3MA
POE. This oil is extremely hydroscopic, meaning it absorbs
water readily. POE oil can absorb 15 times as much water as
other oils designed for HCFC and CFC refrigerants. Take all
necessary precautions to avoid exposure of the oil to the
atmosphere.
POE (polyolester) compressor lubricants are known to cause
long term damage to some synthetic roofing materials.
Procedures which risk oil leakage include, but are not limited to,
compressor replacement, repairing refrigerant leaks, replacing
refrigerant components such as filter drier, pressure switch,
metering device or coil.
Units are shipped with compressor mountings which are
factory-adjusted and ready for operation.
Phasing
Three-phase, scroll compressors operate in only one direction.
If the scroll is drawing low amperage, has similar suction and
discharge pressures, or is producing a high noise level, the
scroll is misphased. Change the incoming line connection
phasing to obtain the proper rotation.
Gas Heat
These single or two stage gas-fired heaters have aluminized-
steel tubular heat exchangers with spark to pilot ignition.
Gas Piping
Proper sizing of gas piping depends on the cubic feet per hour
of gas flow required, specific gravity of the gas and the length of
run. National Fuel Gas Code Z223.1 or CSA B149.1 should be
followed in all cases unless superseded by local codes or gas
company requirements. Refer to Tables 7 and 8.
The heating value of the gas may differ with locality. The value
should be checked with the local gas utility.
NOTE:
There may be a local gas utility requirement specifying
a minimum diameter for gas piping. All units require a
1/2 inch pipe connection at the gas valve.
Gas Connection
The gas supply line can be routed through the hole located on
the left side of the unit. Refer to Figure 3 to locate these access
openings. Typical supply piping arrangements are shown in
Figure 12.
Gas piping requirements:
1.
A drip leg and a ground joint union must be installed in the
gas piping.
2.
When required by local codes, a manual shut-off valve may
have to be installed outside of the unit.
3.
Use wrought iron or steel pipe for all gas lines. Pipe dope
should be applied sparingly to male threads only.
Figure 12: External Supply Connection External Shut-Off
This system uses R-410A Refrigerant which operates at
higher pressures than R-22. No other refrigerant may be
used in this system.
Do not leave the system open to the atmosphere. Unit
damage could occur due to moisture being absorbed by
the
POE oil
in the system. This type of oil is highly
susceptible to moisture absorption
Exposure, even if immediately cleaned up, may cause
embrittlement (leading to cracking) to occur in one year
or more. When performing any service that may risk
exposure of compressor oil to the roof, take precautions
to protect roofing.
Do not loosen compressor mounting bolts.
Scroll compressors require proper rotation to operate
properly. Failure to check and correct rotation may result
in property damage.
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