heat-timer VSP Installation & Operating Instructions Manual page 8

WIRING THE SECONDARY LOOP PUMP
• The Black wires provide a Normally Open (N.O) relay output for the Secondary loop pump.
• The Black wires are a dry contact output only. They do not source any power.
• The Secondary loop pump relay is rated at 8A 1/8HP .
• Use wire nuts, or wrap the connections with electrical tape.
• Class 1 voltages must enter the 1900 box through a different opening from any Class 2 wiring.
• Wire the N.O. dry contacts to the pump starter.
WIRING THE EXT INPUT
• The EXT and COM terminals can only accept a dry contact input. If power is applied across these terminals, the VSP
may be damaged.
• The EXT Input can be configured to provide one of the following two functions:
Setback Mode
• The EXT Input can be used to accept an input from an external clock to lower the temperature of the Secondary loop
when the building is not occupied, or when the occupants are sleeping.
• When the EXT to COM terminals are open, the VSP will run normally.
• When the EXT to COM terminals are shorted together the temperature of the Secondary loop will be reduced by the
number of degrees of Setback (see pg. 13).
Thermostat Mode
• The EXT Input can be used to accept an input from a thermostat to activate the heating system.
• When the EXT to COM terminals are open, the VSP will not be active. Both pump outputs will be disabled.
• When the EXT to COM terminals are shorted together, the VSP will activate the heating system if there is a call for heat
(based on System Start setting described on pg. 11).
SETTING THE OPERATING MODES
• Whenever the VSP is powered up, it will display the software version number and then the current operating modes.
Each display will remain on the screen approximately 5 seconds. If the modes are correct, there is no need to make any
adjustments.
• Once the modes have been set for a particular application, they will be retained in memory and will not need to be reset.
• Note that if you do change an operating mode, you will need to reset all other settings.
• An operating mode can only be changed when it is being displayed in the start-up sequence. To restart the sequence
it is necessary to remove power to the VSP and then power it again.
• Set the operating modes as described in sequence below:
° F or ° C - Fahrenheit or Celsius Temperature Operation
• If the display shows °F then the VSP will operate in Fahrenheit degrees.
• If the display shows °C then the VSP will operate in Celsius degrees.
• To change the mode, hold down the center button while pushing either the UP or DOWN button to toggle between the
displays of °F and °C.
• When the correct temperature mode is selected, release the buttons and wait approximately 5 seconds.
rSt or SP - Reset or Set Point Operation
• If the display shows rSt then the VSP will run with as an outdoor reset control (see pg. 12). As it gets colder outside,
the VSP will automatically increase the temperature of the Secondary loop.
• If the display shows SP then the VSP will hold the selected set point temperature in the Secondary loop. To select the
Set Point, see chart pg. 10.
• To change the mode, hold down the center button while pushing either the UP or DOWN button to toggle between the
displays of rSt and SP.
• When the correct mode is selected, release the buttons and wait approximately 5 seconds.
Sb or thr - Setback or Thermostat Mode
• If the display shows Sb then the VSP will use the EXT Input (see above) for an external clock or switch to lower the
temperature of the Secondary loop.
• If the display shows thr then the VSP will use the EXT Input for a thermostat. When the thermostat input is open,
both pump outputs will be disabled.
• To change the mode, hold down the center button while pushing either the UP or DOWN button to toggle between the
displays of Sb and thr.
• When the correct mode is selected, release the buttons and wait approximately 5 seconds.
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