50HE,HJ
C06137
Fig. 53 --- Humidi-Mizert Hot Gas
Reheat Mode Operation
Hot Gas Reheat Mode
When the humidity levels in the space require humidity control, a hot gas solenoid valve (specific to hot gas reheat mode only) will open to bypass a portion of hot gas refrigerant around the condenser coil. (See Fig. 53.)
This hot gas will mix with liquid refrigerant leaving the condenser coil and flow to the subcooling/reheat dehumidification coil. Now the conditioned air coming off the evaporator will be cooled and dehumidified, but will be warmed to neutral conditions (72_F to 75_F) by the subcooling/reheat dehumidification coil.
The net effect of the rooftop when in hot gas reheat mode is to provide nearly all latent capacity removal from the space when sensible loads diminish (when outdoor temperature conditions are moderate). When in hot gas reheat mode, the unit will operate to provide mostly latent capacity and extremely low sensible heat ratio capability.
Similar to the subcooling mode of operation, hot gas reheat mode operates only when the outside air temperature is warmer than 40_F. Below this temperature, a factory installed outside air temperature switch will lockout this mode of operation.
See Table 36 for the
SERVICE
!WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal injury or death.
When sevicing unit, shut off all electrical power to unit and install lockout tag.
Step 1 —Cleaning
Inspect unit interior at the beginning of heating and cooling season and as operating conditions require.
Evaporator Coil
1.Turn unit power off, tag disconnect. Remove evaporator coil access panel.
2.If economizer or
3.Slide filters out of unit.
4.Clean coil using a commercial coil cleaner or dishwasher detergent in a pressurized spray canister. Wash both sides of coil and flush with clean water. For best results,
5.Reinstall economizer and filters.
6.Reconnect wiring.
7.Replace access panels.
Condenser Coil
Inspect coil monthly. Clean condenser coil annually, and as required by location and outdoor air conditions.
One-Row Coil
Wash coil with commercial coil cleaner. It is not necessary to remove top panel.
2-Row Coils
Clean coil as follows:
1.Turn off unit power and tag disconnect.
2.Remove top panel screws on condenser end of unit.
3.Remove condenser coil corner post. (See Fig. 54.) To hold top panel open, place coil corner post between top panel and center post. (See Fig. 55.)
C06044
Fig. 54 --- Cleaning Condenser Coil
C06045
Fig. 55 --- Propping Up Top Panel
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