User Manual

Page 8
Maximum Value (Fan A3) output only
When controlling 0-10V fans sometimes it is necessary to limit the fan speed to reduce noise or to
protect ducting. The fan output has a high voltage limit setting so regardless of the user selected
speed (High, Medium or Low) or thermostat selected auto speed the 0-10V output will not exceed
this pre-set high limit.
These settings can be found in the installer menu (starting on page 16)
Belimo ™ 6 Way Valve
Belimo™ manufactures an actuator that is in full cooling at 2V, off at 6V and full heating at 10V.
To use this type of actuator with the Smart Temp SMT-131 you must enter the installer menu and
set valve type to “Belimo™ Mode”.
The heating 0-10v output only is used
in this mode
Information on the installer menu
can be found on page 15 of this
manual.
As with normal valves, the 0-10V
heating and cooling span settings in the installer menu scale the heating and cooling outputs.
Factory default is full heating and full cooling 1°C from set point. The heating and cooling span can
be adjusted independently to a maximum of full heating and full cooling 3°C from set point. The
output is linear.
Note When using “Belimo” ™ mode, both the A1 “cool” and the A2 “Heat” 0-10 output are used.
Both will provide the same output to the value. (The A3 “fan” output will remain unchanged and
can be used to control a DC fan or other devices).
2 Pipe Mode
The SMT-131 can measure water temperature via a sensor strapped to the water pipe and wired
into the SMT-131 Sensor input terminals (SI and Com 0-10 input). Based on the pipe
temperature, the room temperature and the set point the SMT-131 will control either the heating
or the cooling outputs to maintain guest comfort. If the pipe temperature is above 30c, the 131 is
in heating mode. If the pipe temperature is below 20c, cooling mode is used. Between 21 and 29
there are no calls. (Version V41.1 firmware and newer the heating and cooling thresholds are
adjustable from within Installer Menu. Option 44 will adjust the heating mode threshold (default
30) and option 45
will adjust the cooling mode threshold (default 20).
When 2 pipe is mode is used, the SMT-131 will open the water valve for 30 seconds every 10
minutes to allow water to flow within the pipe so that the SMT-131 can sample pipe temperature
to determine / confirm operation mode. (Version 41.0 or later firmware will open the valve 25%
for 2 minutes every 10 minutes when heating or cooling is required to check if the water temp is
suitable)
If mode selection is permitted, the SMT-131 will only permit the appropriate mode to be selected
based on the pipe temperature.
To use the SMT-131 in 2 pipe mode set DIP 2 OFF and DIP 4 to the ON position. Set Installer menu
option 27 “Si & Com 0-V” to option “3” – 2 Pipe Mode. (See page 17)