System Service Checks; Heating System Service Checks; Gas Piping; Testing Gas Piping - Lennox KGB Series Unit Information

C - Charge Verification - Approach Method
(Fin/Tube Coil Continued)
1- Using the same thermometer, compare liquid tempera­
ture to outdoor ambient temperature.
Approach Temperature = Liquid temperature (at con­
denser outlet) minus ambient temperature.
2- Approach temperature should match values in table
22. An approach temperature greater than value
shown indicates an undercharge. An approach tem­
perature less than value shown indicates an over­
charge.
3- The approach method is not valid for grossly over or
undercharged systems. Use table 15 through 21 as a
guide for typical operating pressures.
TABLE 22
APPROACH TEMPERATURE - Fin/Tube - TXV
Liquid Temp. Minus Ambient Temp.
KG/KC Unit
024S, 030S,
036S, 090S
048S
060S
074S
D - Charge Verification - Subcooling Method AHRI Testing
(Fin/Tube Coil Continued)
1- Attach gauge manifold to the liquid line. With the econ­
omizer disabled, operate the unit in cooling mode (at
high speed on 2-speed units).
2- Use the liquid line pressure and a PT chart to determine
the saturated liquid temperature.
3- Measure the liquid line temperature at the condenser
outlet.
Subcooling Temperature = Liquid Saturated Tempera­
ture Minus Liquid Temperature.
4- The subcooling temperature should be as shown in fig­
ure 23. A subcooling temperature greater than this val­
ue indicates an overcharge. A subcooling temperature
less than this value indicates an undercharge.
TABLE 23
SUBCOOLING TEMPERATURE
Liquid Saturated Temp. Minus
KCB/KGB Unit
024S
030S
036S, 060S
048S
074S
090S
1°F + 1 (0.6°C + 0.5)
2°F + 1 (1.1°C + 0.5)
3°F + 1 (1.7°C + 0.5)
4°F + 1 (2.2°C + 0.5)
Liquid Temperature
7°F + 1 (3.9°C + 0.5)
8°F + 1 (4.4°C + 0.5)
9.5F + 1 (5.2°C + 0.5)
11.5°F + 1 (6.3°C + 0.5)
12.5°F + 1 (6.9°C + 0.5)
10°F + 1 (5.5°C + 0.5)
V- SYSTEM SERVICE CHECKS
A-Heating System Service Checks
All KGB units are C.S.A. design certified without modifi­
cation.
Before checking piping, check with gas company or au­
thorities having jurisdiction for local code requirements.
Refer to the KGB Installation instruction for more infor­
mation.

1-Gas Piping

Gas supply piping must not allow more than 0.5"W.C.
(124.3 Pa) drop in pressure between the gas meter and
the unit. Supply gas pipe must not be smaller than the unit
gas connection. Refer to installation instructions for de­
tails.

2-Testing Gas Piping

NOTE-In case emergency shutdown is required, turn off
the main manual shut‐off valve and disconnect the main
power to the unit. These controls should be properly la­
beled by the installer.
When pressure testing gas lines, the gas valve must be dis­
connected and isolated. Gas valves can be damaged if
subjected to more than 0.5 psig [14"W.C. (3481 Pa)]. See
figure 22.
GAS PIPING COMPONENTS
REFER TO INSTALLATION INSTRUCTIONS
GROUND
JOINT UNION
MANUAL MAIN
SHUT-OFF VALVE
(REFER TO LOCAL CODES)
When checking piping connection for gas leaks, use the
preferred means. Common kitchen detergents can
cause harmful corrosion on various metals used in gas
piping. The use of specialty Gas Leak Detector is strong­
ly recommended. It is available through part number
31B2001. See CORP 8411-L10, for further details.
Do not use matches, candles, flame or any other source of
ignition to check for gas leaks.
Page 60
VALVE
CAP HERE TO
UNIT
ISOLATE VALVE
WHEN PRESSURE
TESTING LINE
ROOF
MOUNTING
FRAME
DRIP LEG
GAS PIPING
SUPPORT
FIGURE 22