4.18 - Reclaim Operation
4.18.1 - General Description
This function shall control the air cooled to reclaim or the reclaim to air cooled changeover process.
Reclaim changeover shall be caused either by:
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A manual reclaim select change due to a local, remote or CCN command on the unit
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A heat reclaim temperature change while reclaim has been selected. This algorithm monitors the entering
reclaim sensor temperature and compares it with the reclaim setpoint to determine if the reclaim can be active
or not.
If the reclaim function has been selected, the reclaim shall become active when the entering reclaim temperature
comes below the reclaim setpoint minus the reclaim deadband and delay between the last air cooled to reclaim
session is elapsed. It shall become inactive when the entering reclaim temperature comes over the reclaim setpoint
plus the reclaim deadband.
Non-reclaim to reclaim Changeover shall follow this procedure:
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Turn on the reclaim condenser pump
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Verify the condenser flow is established, if not after 1 minute delay has elapsed, reclaim operation shall be
aborted and an alarm shall be displayed.
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Wait for 3 minutes after condenser pump is ON and until the saturated condensing temperature reaches (30
deg C) and superheat is greater than 8.6 ^C
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If saturated condensing temperature is greater than reclaim se 3.3^F, go to reclaim operation directly (it
is not necessary to make an pumpdown) otherwise, go through pumpdown (see below)
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Start the pumpdown sequence : reclaim discharge valve shall be closed and reclaim pumpdown injection valve
shall be open.
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Close EXV 6.67 or 3.33% upon the number of compressors on circuit every 10 seconds while pumpdown
pressure is greater than 300 kpa (44 psi), during first minute if EXV is less than 15 % opened.
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After a 10 minutes duration or as soon as pumpdown pressure is lower than 300 kpa (44 psi), reclaim injection
valve shall be closed, reclaim operation is effective. Open EXV 13.33% as avoid low saturated suction alarm.
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When reclaim operation is active, each circuit fan staging has its own saturated condensing control point
determined as follows:
sct_ctrl_x = ( hr_lwt)/ 2 + rsp_x_a * capa rsp_x_b (x for circuit), rsp_x_a and rsp_x_b are
service parameters in table SERVICE2.
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Pumpdown shall not be necessary if saturated condensing temperature is greater than reclaim se 6 ^C
Reclaim to non-reclaim Changeover shall follow this procedure:
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Turn off the condenser pump.
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Close the reclaim pumpdown valve.
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Open the reclaim discharge valve if at least a compressor is ON. Otherwise, Close it.
During reclaim operation, if the pumpdown pressure is greater than 400 kpa (59 psi), the pumpdown procedure in
non_reclaim to reclaim session shall be initiated. When the number of these abnormal sessions exceeds 2 times,
the reclaim operation shall be aborted, the circuit shall return to air cooled mode and an alarm shall be displayed.
At power up or after reset or after the unit capacity goes down to 0%, the function shall return to air cooled mode.
4.18.2 - Reclaim To Air Cooled Changeover Initiation
This shall determine whether the unit shall return to air cooled mode. This can be caused by the following:
Cause #1: Reclaim operation active and reclaim select is no more active
Cause #2: Reclaim mode is active and the entering reclaim temperature is above the range of the reclaim
setpoint + the reclaim dead band divided by 2 : HR_EWT >rsp + hr_deadb/2
Cause #3: Number of consecutive reclaim pumpdown sessions exceeds 2 times
Cause #4: entering reclaim temperature sensor failure
CARRIER SA
USER'S GUIDE FOR
30GX&HX PRO_DIALOG 4 V.2
ECG-UG-02-002
Rev: Original
Page: 51/98
©
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ARRIER
S
.
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