Timer Speedup/Test Mode; Auxiliary Heat Lockout - Carrier GZ024 Installation Instructions Manual

protector closes, (at the next 15 minute interval check) the unit
will resume operation. If the thermal protector trips for three
consecutive cycles, then unit operation is locked out for 4 hours
and the appropriate fault code is displayed.
S NO 230V AT COMPRESSOR CONTACTOR: If the
compressor voltage is not sensed when the compressor should be
starting, the appropriate contactor may be stuck open or there is a
wiring error. The control will flash the appropriate fault code.
Check the contactor and control box wiring. Refer to Table 11
and Fig. 24.
Table 11 – UPM Voltage Detection
UPM Voltage Detection
Brownout L1 and L2
Compressor voltage sensing VS and L1
230V line power disconnect detection on L1
and L2
Contactor shorted detection VS and L1
24V transformer Sec 1 and Sec 2
Fig. 24 - - UPM Board
L1, L2, VS, SEC 1 and SEC 2 Locations
TIMER SPEED- -UP (TEST MODE)
Timer Speed Up allows the unit to bypass all start timings to below
10 seconds to allow the unit to run for testing purposes. This speed
up will last one cycle until unit shuts down for the next start.
Start timings include:
S Anti- -short cycle time (5 minutes)
S Random startup
On a system with a communicating control, from the main menu,
enter the Service mode by holding the Service hat icon for
approximately 10 seconds until it turns green. Enter the checkout
screen. This allows an option to run 5 minutes low stage or 5
minutes high stage, each adjustable up to 120 minutes and
stoppable at any time.
The following applies to GZ split units used with a gas furnace or
fan coil with electric heat:
When using the GZ communicating units, the "Lock- -out" feature
for the gas furnace or electric heat is not enabled on the
Infinity/Evolution wall control. The wall control is "in charge" of
the comfort and the staging. Staging is not to be controlled by a
one time set- -up selection or by a temporary manual override.
When the GHP is no longer able to satisfy the thermostat in first or
second stage heating, operation will automatically switch from the
GHP to the gas furnace or electric heat, which will remain in
Fault Code
operation until the thermostat is satisfied. Although some
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customers want control of that changeover point based on a set
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outdoor air temperature, this can negatively affect the comfort and
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performance of the GHP.
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S If the changeover temperature would be set too high, then the
No faults
GHP would not be providing the customer with the best
efficiency due to extended operation (run hours) of the gas
furnace or electric heat resulting in higher energy costs than the
customer anticipated.
S If the changeover temperature would be set too low, then the GHP
would operate in conditions outside its design condition resulting
in poor performance. For example, if the GHP and loop are sized
to provide all the heating requirements down to 15_F prior to
auxiliary heat (gas furnace or electric heat operation), then
operating the GHP at outdoor temperatures lower than 15 _F
would result in continuous run times, reducing the loop
temperature lower than its design condition. The lower loop
temperature then results in lower capacity for the GHP, causing it
to keep running in an attempt to satisfy the thermostat. The loop
will continue to drop in temperature, causing further reduction in
capacity and efficiency. This results in a negative "fly wheel"
effect that is inescapable unless auxiliary heat is used or the
outdoor temperature increases.
S In an open loop/well water application where the changeover
temperature would be set too low and auxiliary heat was
locked- -out, the unit would not be able to maintain the heating set
point and comfort would be compromised.
S The wall control takes the guesswork out of determining the
change- -over set- -point and ensures that comfort and performance
are not compromised.
Emerging From Set- -Back
Some key operational features to consider are below:
In set- -back (heating) mode:
S When coming out of set- -back, the system will always first engage
the GHP in first stage heat, then second stage heat, then auxiliary
back- -up (electric resistance or furnace).
S The system uses intelligent recovery.
S Back- -up heat is not engaged until it has been determined by the
control that second stage heat is not satisfying the thermostat.
If the homeowner manually bumps up the heating setpoint several
degrees:
S The system will always first engage the GHP in first stage heat,
then second stage heat, then auxiliary back- -up (electric resistance
or furnace).
S Back- -up heat is not engaged until it has been determined by the
control that second stage heat is not satisfying the thermostat.
S The duration of this attempt varies based on the rate of
temperature rise and the difference in set- -point, but is typically
less than 30 minutes. The reason behind this is that the system
thinks that if the homeowner increases the setpoint from, for
example 70_ to 74_, the extra heat is wanted now.
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AUXILIARY HEAT LOCKOUT