128 RT-SVD03G-EN
Modulating Dehumidification with Hot Gas Reheat
(27.5-50 Tons)
Controls Overview
• Reheat LPC (RTDM input)
• Manual lockout after four trips.
• Additional 60# low pressure cutout ignored for the first 10 minutes of compressor run time
in reheat mode.
• Will also be active during service test.
• Two Modulating valves are controlled by the leaving unit temperature sensor
• Cooling mode: Cooling valve 100% open, Reheat valve 0% open.
• Reheat mode: Cooling and Reheat valves open/close inverse of each other. Reheat valve
allowed to operate from 15 to 85% open.
• Reheat pump out solenoid
• Energized when in cooling mode. It is inactive in all other modes.
• A three minutes purge cycle will take place after one continuous hour (hard coded) of
operation in reheat or cooling mode.
• Entering Evaporator Temperature (overrides Frostat during reheat)
• During reheat operation if the temp is below 35º F for 10 minutes the control will shed
compressors (or circuits).
• The unit will not be allowed to stage up until leaving reheat.
• If the temp is below 35º F for 10 more continuous minutes all compressors will stage off and
the ID fan will continue to run.
• Once reaching 45º F the compressor (circuit) will be re-enabled.
• The condenser fans will be staged differently in reheat mode than cooling mode.
• Single circuit units (3 total condenser fans): A maximum of 2 outdoor fans above 85º F and
a maximum of 1 outdoor fan below 80º F.
• Dual circuit units (4 total condenser fans): A maximum of 4 outdoor fans above 85º F and
a maximum of 2 outdoor fans below 80º F.
• Service mode operation
• Reheat step will follow the last cooling step in service test mode.
• All compressors energized.
• Reheat / Cooling Modulating valve positions are 50%.
• Pump out solenoid de-energized.
• 60 minute service test interval timer will be in control.
To Next Page
Loading...
