Powtier Controls Limited
505MST Thermostat
Instruction Manual
Table A, Output switching (SW3=0, SW4=0)
Output
State
Temperature
Description
H3
OFF
18.5°C
16KW ON
ON
17.5°C
24KW ON
H2
OFF
20.5°C
8KW ON
ON
19.5°C
16KW ON
H1
OFF
21.5°C
Heat OFF
ON
20.5°C
8KW ON
LLDS
ON
21.5°C
LLDS energised (no timer)
TD then OFF
20.5°C
After timer-delay (TD), LLDS de-en ergised
C
ON
22.5°C
Cooling ON
OFF
21.5°C
Cooling OFF
Table B, Output switching (SW3=0, SW4=1)
Output
State
Temperature
Description
H3
OFF
19.5°C
16KW ON
ON
18.5°C
24KW ON
H2
OFF
20.5°C
8KW ON
ON
19.5°C
16KW ON
H1
OFF
22.5°C
Heat OFF
ON
21.5°C
8KW ON
LLDS
ON
22.5°C
LLDS energised (no timer)
TD then OFF
21.5°C
After timer-delay (TD), LLDS de-en ergised
C
ON
23.5°C
Cooling ON
OFF
22.5°C
Cooling OFF
Table C, Output switching (SW3=1, SW4=0)
Output
State
Temperature
Description
H3
OFF
20.5°C
16KW ON
ON
19.5°C
24KW ON
H2
OFF
22.5°C
8KW ON
ON
21.5°C
16KW ON
H1
OFF
23.5°C
Heat OFF
ON
22.5°C
8KW ON
LLDS
ON
23.5°C
LLDS energised (no timer)
TD then OFF
22.5°C
After timer-delay (TD), LLDS de-en ergised
C
ON
24.5°C
Cooling ON
OFF
23.5°C
Cooling OFF
H3 - Heater 3; H2 - Heater 2; H1 - Heater 1; C - Cool; LLDS - Low level damper solenoid.
Automatic winter/summer switching
An ambient sensor is fitted inside the thermostat unit and must be exposed to the ambient
temperature.
There are three possible winter/summer switching temperature, the selections are made using
the (SW1 and SW2) of the 4-way (dual-in-line) switch. See Table S1.
505MSTIM
Page 3
29 June 1998
Issue 1.0
