McQuay MDS 100B

12 Service Manual SM-MDS_(ii)
2.4 Heater Control
There is an optional heater for MDS indoor unit. However, this option is only applicable for ducted model (using
wired controller) and it will function during heating cycle or fan mode. (Please refer to page 48 for dipswitch
setting on heater application). User can choose to install one or two heaters. The control algorithm of the heaters
is shown below:
1 Heater
T
r
T
s
0.5-1
When the set temperature (T
s
) is higher than room temperature (T
r
) by 0.5°C, the heater will be
turned ON.
(Ts - Tr > 0.5)
When the set temperature (T
s
) is lower than room temperature (T
r
) by 1°C, the heater will be
turned OFF.
(Ts - Tr < -1)
2 Heater
T
r
T
s
0.5-1 1-0.5
Heater 1
When the set temperature (T
s
) is higher than room temperature (T
r
) by 0.5°C, the heater will be
turned ON.
(Ts - Tr > 0.5)
When the set temperature (T
s
) is lower than room temperature (T
r
) by 0.5°C, the heater will be
turned OFF.
(Ts - Tr < -0.5)
Heater 2
When the set temperature (T
s
) is higher than room temperature (T
r
) by 1°C, the heater will be
turned ON.
(Ts - Tr > 1)
When the set temperature (T
s
) is lower than room temperature (T
r
) by 1°C, the heater will be
turned OFF.
(Ts - Tr < -1)
2