Table of Contents
28 | Initial Start-Up
INITIAL START-UP
NOTICE: Make sure all valves in heat
recovery water piping system are open.
NEVER OPERATE HR PUMP DRY.
1.
Turn on the heat pump. The HR pump should not run
if the compressor is not running.
2.
Turn HR switch to the "ON" position. The pump will
operate if entering water temperature to HR is
below 120° F.
3.
The temperature difference between the water
entering and leaving the heat recovery should be 5°
to 15° F.
4.
Allow the unit to operate for 20 to 30 minutes to
ensure it is functioning properly. The pump should
shut off when the water temperature entering the
heat recovery reaches 120°F.
SEQUENCE OF OPERATION
Cooling Mode
Energizing the "O" terminal energizes the unit reversing
valve thus placing the unit into cooling mode. The fan
motor starts when the "G" terminal is energized.
The fan motor will take 30 seconds to ramp up to
operating speed and will run at fan only rated air flow
as long as there is no call for compressor or heater
operation.
When the thermostat calls for first stage cooling (Y1) the
loop pump or solenoid valve if present is energized and
the first stage of compressor capacity starts. The fan
ramps up to first stage cooling air flow in 30 seconds.
Some options will have a built in delay, and hence,
compressor operation is not immediate. See
'Options' sections for more detail.
When the thermostat calls for second stage cooling (Y2)
the second stage (or full compressor capacity) is
initiated. The fan ramps up to full cooling air flow.
Once the thermostat is satisfied, the compressor shuts
down and the fan ramps down to either fan only mode or
off over a span of 30 seconds.
Note that a fault condition initiating a lockout will
de-energize the compressor irrespective of which
stage is engaged.
8733942411 (2017/07)
Heating Mode
The first two stages of heating (Y1 & Y2) operate in the
same manner as cooling, but with the reversing valve de-
energized. On a call for auxiliary heat (W1), the fan
ramps up to auxiliary heat air flow immediately and the
electric heater package is energized along with the
compressor.
As the thermostat is satisfied, the heaters will shut off as
soon as W1 is de-energized, and the compressors will
remain on until the thermostat stages are satisfied.
If the unit compressor locks out for any reason at this
time, the electric heaters will continue to function
normally.
Once the thermostat is satisfied, the compressor shuts
down and the fan ramps down either fan only mode or
off over a span of 30 seconds. If thermostat has two
different output points one for Auxiliary heat and a
different one for Emergency heat the two outputs must
be terminated on W1 units equipped with one stage of
Electric heat.
When using a 2-cool, 3-heat thermostat both the W1
& W2 on the Heat Pump and W2 & EM on the
thermostat must be connected together via a jumper.
(See Figure#54)
Subject to change without prior notice
SM Series Heat Pump
SM Series Heat Pump
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