Zehnder Rittling VS Series Installation, Operation And Maintenance Manual page 50

Unit start-up
procedure
48
Turn on line power to all
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■
heat pumps. See controls
description for details.
Turn the thermostat fan
■
■
position to "ON." Blower
should start.
Balance air flow at registers.
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■
Adjust all water valves to their
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■
full open positions.
Room and entering water
■
■
temperatures should be within
the minimum-maximum ranges
of Tables 12 and 13. During
start-up checks, loop water
temperature entering the heat
pump should be between 60 °F
(16 °C) and 95 °F (35 °C).
Two factors determine the
operating limits of Zehnder
Rittling heat pumps, (a) return air
temperature, and (b) supply water
temperature. When any one of
these factors is at a minimum or
maximum level, the other factor
must be at normal level to ensure
proper unit operation.
Cooling
Adjust the unit thermostat to
■
■
the warmest setting. Place the
thermostat mode switch in the
"COOL" position. Incrementally
reduce thermostat setting
1° every 1 minute until the
compressor activates.
Check for cool air delivery
■
■
at the unit grille within a few
minutes after the unit has
begun to operate. Verify that
the compressor is on and
that the water flow direction
is correct by measuring
pressure drop through the heat
exchanger.
Units have a 3-5 minute time
delay in the control circuit
that can be eliminated on the
microprocessor control board.
See test mode described in the
dip switch settings section, refer
to page 40.
Check the elevation and
■
■
cleanliness of the condensate
lines. Dripping may be a sign
of a blocked line. Check that
the condensate trap is filled to
provide a water seal.
Check the temperature of both
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■
entering and leaving water. If
temperature is within range,
proceed with the test (see
Table 15). If temperature is
outside of operating range,
check refrigerant pressures.
Table 15: Temperature
change through
heat exchanger
Rise in Drop in
Water flow
cooling heating
Closed loop @
9-12 °F
3 GPM/ton
(5-6.7 °C) (2.2-4.4 °C)
(3.9 l/m/kW)
Open loop @ 20-26 °F
10-17 °F
2.5 GPM/ton (11.1-14.4
(5.6-9.4 °C)
(2.0 l/m/kW) °C)
Check air temperature drop
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■
across the air coil when
compressor is operating. Air
temperature drop should be
between 15 °F and 25 °F (8 °C
and 14 °C).
Turn thermostat to "OFF"
■
■
position. A hissing noise may
be heard and indicates proper
functioning of the reversing
valve.
Allow 5 minutes between tests
■
■
for pressure to equalize before
beginning heating test.
4-8 °F