To Next Page

To Previous Page

86•dap4UserManual

c) High Relative humidity Limit in dewpoint control

 • Ifhighrelativehumidityconditionoccurswhilehumiditycontrolmodeissetto

Dewpoint control then dewpoint control has priority over the relative humidity control.

 • Ifhighdewpointsetpointsatisesbutrelativehumidityrisestorelativehumidity

  setpoint,thedehumidicationcontrolwillbeasfollows:

i) Single Variable speed compressor system

 Dehumidicationcycleson:

If unit is not in cooling mode, the variable speed compressor turns on when humidity is at

Humidity Setpoint (HSP) -1%.Compressor will modulate from 0% to 100%, 10% speed for

every 0.1%RH. Compressor will run at 100% when humidity equals humidity setpoint.

 Dehumidicationcyclesoff:

Variable speed compressor C1 starts to ramp down in 10 % decrement when Humidity

drops to Humdity Setpoint –humidity deadband. Compressor will run at minimum speed

(0 VDC) when humidity equals humidity setpoint – humidity deadband- 1%.Compressor

turns off when Humidity = Humidity Setpoint – humidity deadband- 1.5 % and minimum

 runtimeexpired.

ii) Dual circuit with a variable speed compressor and a xed speed compressor

 Dehumidicationcycleson:

 Ifunitisnotincoolingmode,C2xedspeedcompressorturnsonwhenhumidityreaches

Humidity Setpoint (HSP). Compressor will not violate the compressor short cycle regulation.

 Dehumidicationcyclesoff:

Compressor C2 turns off when humidity = humidity setpoint- humidity deadband.

Safeties and Alarms for System with Electronic Expansion Valve (EEV)

i High suction temperature alarm.

The variable speed compressor’s suction temperature can be viewed on dap4.

Compressors’ high suction temperature alarm limits is default to 85oF (the range is 80-

95°F) and a suction temperature deadband is default to 5 oF(1-5°F).

a. When C1 has been running for 3 minutes and suction temperature is higher than the

alarm setpoint, C1 high suction temperature alarm will activate.

b. C1 compressor will shut down during high suction temperature alarm. Alarm will

automatically reset if suction temperature falls below the high suction temperature

alarm limit minus the deadband and the variable speed compressor resumes

operation if high suction temperature alarm has been cleared for 5 minutes.

c. An alarm message on dap4 display will notify the end-user that compressors

lock-out are delayed by high suction temperature alarm time-out during this 5

minutes time-out.

Data Aire dap 4 User Manual

Questions and Answers: