Manual 2100-742A
Page
26 of 54
START UP
General
1. Use separate service equipment to avoid cross
contamination of oil and refrigerants.
2. Use recovery equipment rated for R-410A
refrigerant.
3. Use manifold gauges rated for R-410A (800
psi/250 psi low).
4. R-410A is a binary blend of HFC-32 and HFC-125.
5. R-410A is nearly azeotropic—similar to R-22 and
R-12. Although nearly azeotropic, charge with
liquid refrigerant.
6. R-410A operates at 40-70% higher pressure
than R-22 and systems designed for R-22 cannot
withstand this higher pressure.
7. R-410A has an ozone depletion potential of zero,
but must be reclaimed due to its global warming
potential.
8. R-410A compressors use polyol ester oil.
9. Polyol ester oil is hygroscopic; it will rapidly absorb
moisture and strongly hold this moisture in the oil.
10. A liquid line dryer must be used—even a deep
vacuum will not separate moisture from the oil.
11. Limit atmospheric exposure to 15 minutes.
12. If compressor removal is necessary, always plug
compressor immediately after removal. Purge with
small amount of nitrogen when inserting plugs.
Topping Off System Charge
If a leak has occurred in the system, Bard
Manufacturing recommends reclaiming, evacuating
(see criteria above) and charging to the nameplate
charge. If done correctly, topping off the system charge
can be done without problems.
With R-410A, there are no significant changes in the
refrigerant composition during multiple leaks and
recharges. R-410A refrigerant is close to being an
azeotropic blend (it behaves like a pure compound
or single component refrigerant). The remaining
refrigerant charge, in the system, may be used after
leaks have occurred and then “top-off” the charge by
utilizing the pressure charts on the inner control panel
cover as a guideline.
REMEMBER:
When adding R-410A refrigerant, it must
come out of the charging cylinder/tank as a liquid to
avoid any fractionation, and to ensure optimal system
performance. Refer to instructions for the cylinder that
is being utilized for proper method of liquid extraction.
Safety Practices
1. Never mix R-410A with other refrigerants.
2. Use gloves and safety glasses. Polyol ester oils can
be irritating to the skin, and liquid refrigerant will
freeze the skin.
3. Never use air and R-410A to leak check; the
mixture may become flammable.
4. Do not inhale R-410A—the vapor attacks
the nervous system, creating dizziness, loss
of coordination and slurred speech. Cardiac
irregularities, unconsciousness and ultimate death
can result from breathing this concentration.
5. Do not burn R-410A. This decomposition produces
hazardous vapors. Evacuate the area if exposed.
6. Use only cylinders rated DOT4BA/4BW 400.
7. Never fill cylinders over 80% of total capacity.
8. Store cylinders in a cool area, out of direct
sunlight.
9. Never heat cylinders above 125°F.
10. Never trap liquid R-410A in manifold sets, gauge
lines or cylinders. R-410A expands significantly at
warmer temperatures. Once a cylinder or line is full
of liquid, any further rise in temperature will cause
it to burst.
Important Installer Notes
For improved start up performance, wash the indoor
coil with a dishwashing detergent.
Dehumidification Models
Exposure to high pressure refrigerant hazard.
Dehumidification models are equipped with an
electronic expansion valve (EEV). In order to fully
recover refrigerant or evacuate system during repairs,
either use service tool P/N 2151-021 to manually open
the EEV or be sure to recover and evacuate from all
service ports: suction, liquid and discharge.
Failure to do so could result in eye injuries and/or
refrigerant burns.
High and Low Pressure Switches
All Q**H4 series models are supplied with high and low
pressure switches that reset automatically in response
to system pressures. High pressure switch settings:
Opens 650 +/– 15 PSI, closes 520 +/– 15 PSI. Low
These units require R-410A refrigerant and
polyol ester oil.
