tekmar 557 Thermostat Installation - Manual (Page 39)

© 2014 557_D - 09/14
39 of 52 A Watts Water Technologies Company
Relative Humidity Operation Section F
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.
Operation Mode Required
Relay(s) Sensor
Required
Stand Alone Humidifier
Humidifier operates independently of the HVAC
system.
Available in all modes except off. HM1 ACC RELAY
= HUM None
Humidifier with Fan
Humidifier ducted together with HVAC system.
The system fan is operated whenever the humidi-
fier is operating.
Available in all modes except off. HM2 ACC RELAY
= HUM None
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. HM3 ACC RELAY
= HUM None