Powtier Controls Limited
505MST Thermostat
Instruction Manual
Installation
Please refer to System layout diagram for details.
Fixings
The 505MST/M thermostat unit could be mounted in any orientation by 4xM6 fixing holes.
Electrical connection
Please refer to System connection diagram for details.
Supply connection
The 505MST/M thermostat is powered by a 110Vdc and connection is made to the M4 stud
terminal marked "0" and "110".
The `0' volt terminal is to be connected to an external earth point (it is not connected to the
thermostat internal earth).
The thermostat 110Vdc inputs are reverse polarity protected.
Output connection
There are six M4 stud terminals for output connection: A1, A2, A3, A4, A5 and A6.
The A1 terminal is connected to the "COMMON"' of the five thermostat relays.
Terminals A2, A3 and A4 are connected to external heater contactors, namely: Heater 3 (via
FADSR), Heater 2 and Heater 1 respectively.
Terminal A5 is connected to drive the Lower lever damper solenoid (LLDS).
Terminal A6 is connected to the external Cool contactor.
Supply and outputs Terminal
Terminals
Descriptions
A1
Common supply of output relays,
415Vac or 110Vdc
A2
Heater 3 and Fresh air damper
A3
Heater 2
A4
Heater 1
A5
Lower level damper solenoid
A6
Cooling
0V
Supply 0Vdc
110Vdc
Supply 110Vdc
505MSTIM
Page 7
29 June 1998
Issue 1.0