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TABLE 38
Manufacturer
Nominal Signal
Microamps
Drop Out
UTEC 0.5 - 1.0
NOTE-If the meter scale reads 0, the leads are reversed.
Disconnect power and reconnect leads for proper polarity
10-Combustion Air Inducer
adjustable. However, operation should be monitored to
ensure proper operation. The combustion air inducer is
used to draw fresh air into the combustion chamber while
simultaneously expelling exhaust gases. The inducer op-
erates throughout the heating cycle.
On a heating demand, the ignition control is energized by
the A55 Unit Controller. The ignition control then allows
30 to 40 seconds for the combustion air inducer to vent
exhaust gases from the burners. When the combustion
air inducer is purging the exhaust gases, the combustion
air prove switch is closing proving that the combustion air
inducer is operating before allowing the ignition control to
energize. When the combustion air prove switch is closed
11-High Altitude
Units may be installed at altitudes up to 2000 feet (610
above 2000 ft see “HIGH ALTITUDE DERATE” in “SPECI-
FICATIONS - GAS HEAT” at the front this manual.
B-Cooling System Service Checks
LGH units are factory charged and require no further ad-
using the approach method. The approach method com-
pares actual liquid temperature with the outdoor ambient
temperature. See section III- CHARGING.
NOTE-When unit is properly charged discharge line pres-
sures should approximate those in tables 11 through 36.
1-Oil Check Injection Procedure 180U, 240U, 300U
1 - Run the unit in full load (both compressors running)
for a minimum of thirty (30) minutes or until
2 - Check the oil level of the tandem compressor
assembly using the sight glass installed in the oil
equalization line near the base of the compressors.
The oil level should be visible in the sight glass,
preferably in the middle.
3 - If the oil level is not visible in the sight glass continue
on to steps 4-17 to add oil to the tandem compressor
system( POE 32-3MAF oil recommended). The A/C
catalogue number Y6630 is recommended for use
when adding oil to a system.
4 - With the unit running in full load, connect the high
side manifold gauge hose to the open pressure tap
valve to purge the high side and middle manifold
gauge hoses.
5 - Connect the oil injector container to the middle
manifold gauge hose. Remove the container from
the lid (the end attached to the middle manifold
gauge hose).
6 - Attach a hose to the opposite end of the oil container
(this hose is provided and is already attached to the
oil container in the recommended injection kit listed
above).
7 - Clean the oil container of contaminants and debris.
the oil container (POE 32-3MAF oil recommended).
8 - Re-install the lid, attached to the middle manifold
gauge hose, onto the oil container.
side manifold gauge valve to pressurize the hoses
and oil container.
10 - Lightly thread the hose coming from the oil
the oil equalization line located near the base of the
compressors (See Figure 31). Do not depress the
Schrader Valve..
11 -
the oil equalization line port.
12 -
gauge hose and the oil container to pressurize with
suction pressure.
13 - Open the high side manifold gauge valve for no
more than 2 seconds to allow the contents of the oil
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