Liebert TM-10098 iCOM Controls Training and Service Manual, ParameterOperation, No Normal Delayed

iCOM Controls Training and Service Manual

dehumidification process. The end user can choose to select from the following selections:

Parameter Operation

No

Normal

Delayed

No electric reheat allowed during compressorized dehumidification operation.

Electric reheat operates as normal. A decrease in return air temperature below set point will start reheats as described previously in his chapter.

No low limit reached / low limit reset: heaters disabled. Only one of two compressors operating in dehum or low limit 1 reached: heaters enabled

Normal or Delayed Reheat (2-Stage Dehumidification Only)

When normal reheat (factory default) control is selected, the unit reheats are not disabled during dehumidification, even if both compressors are operating. As the return air temperature decreases below the temperature set point the reheats will stage on and off as described earlier in this chapter.

If delayed reheat is selected and both compressors are operating for dehumidification control, the reheats are disabled until only one compressor is required. If, during reheat disable, the return air temperature decreases far enough below the temperature set point to require 150% total available reheat capacity, then dehumidification is disabled and reheats are activated.

When the return temperature raises to the point where reheat is no longer required, then dehumidification operation is re-enabled. However, if the amount of time that both compressors were operating prior to being disabled by the low temperature condition was less than 10 minutes, then only one compressor is allowed to operate for subsequent dehumidification requirements. This prevents excessive system cycling, which can occur if the room heat load is small. Once the requirement for dehumidification is no longer present, then both compressors are enabled.

Caution:

Dehumidification with normal reheat allows for operating both compressors and reheats simultaneously. It is very important that the electrical service to the unit be sized and wired for this option if selected. If not sized properly the electrical service could experience nuisance trips and or possible damage to building circuit breakers (or Fuses) and wiring.

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