tekmar 553 Thermostat Installation User Manual
Page 39
© 2014
553_D - 09/14
39 of 52
A Watts Water Technologies Company
Relative Humidity Operation
Section H
Relative Humidity (RH) is controlled by maintaining the Minimum Humidity using
humidification and by maintaining Maximum Humidity using dehumidification. The RH
is maintained within a 5% differential. The differential is applied above the minimum
setpoint, and applied below the maximum setpoint. When the mode is set to off, the
humidification and dehumidification systems do not operate.
To avoid condensation on windows, the minimum relative humidity setting can be
changed according to the following outdoor temperatures.
Outdoor Temperature -10°F (-23°C) 0°F (-18°C)
10°F (-12°C) 20°F (-7°C)
30°F (-1°C)
Suggested RH Min
20%
25%
30%
35%
35%
The thermostat has three humidification modes.
Mode
Operation
HM1
Stand Alone Humidifier
Humidifier operates independently of the HVAC system.
Available in all modes except off.
HM2
Humidifier with Fan
Humidifier ducted together with HVAC system. The system fan is oper-
ated whenever the humidifier is operating. This is only available when
operating a conventional heating system with a fan.
Available in all modes except off.
HM3
Humidifier with Air Heating
Humidifier ducted together with HVAC system. The air system must be
heating (heat pump, furnace, electric or hydronic fan coil) in order to
allow the humidifier to operate.
Available when heating.
The thermostat has three dehumidification modes.
Mode
Operation
DHM1
Stand Alone Dehumidifier
Dehumidifier operates independently of the HVAC system.
Available in all modes except off.
DHM2
Coil Dehumidification
A DX coil compressor is operated with the blower fan operating at its
dehumidification speed.
DHM3
HRV Dehumidification
(requires an outdoor temperature reading to be available)
The HRV is operated based upon indoor dew point and outdoor air tem-
perature. The HRV operates when the indoor dew point is 5.5°F (3.0°C)
above the outdoor temperature. The HRV is shut off when the indoor dew
point falls to 2°F (1.0°C) above the outdoor temperature.
Available in all modes except off.