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Table 8. Merit
®
CBX25UHV‐048 Air Handler Performance (0 through 0.80 in. w.g. [0 — 200 Pa] External Static Pressure Range)
“ADJUST”
Jumper
Setting
Jumper Speed Positions
“HEAT” Speed
First-Stage “COOL” Speed
Second-Stage “COOL” Speed
1
2
3
4
1
2
3
4
1
2
3
4
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
+
1450
1670
1880
2340
1050
1200
1340
1650
1440
1670
1950
2340
NORM
1340
1520
1730
2100
950
1100
1230
1520
1325
1530
1740
2150
–
1210
1390
1570
1915
850
1000
1110
1375
1200
1380
1600
1950
NOTES
The effect of static pressure, filter and electric heater resistance is included in the air volumes listed.
First-stage cooling air volume is 70% of COOL (second-stage) speed setting. Continuous blower speed is approximately 50% of COOL speed setting.
Lennox Harmony III™ Zoning System applications minimum blower speed is 450 cfm.
Table 9. Merit
®
CBX25UHV‐060 Air Handler Performance (0 through 0.80 in. w.g. [0 — 200 Pa] External Static Pressure Range)
“ADJUST”
Jumper
Setting
Jumper Speed Positions
“HEAT” Speed
First-Stage “COOL” Speed
Second-Stage “COOL” Speed
1
2
3
4
1
2
3
4
1
2
3
4
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
cfm
+
1700
1930
2120
2275
1225
1410
1530
1690
1720
1930
2140
2270
NORM
1570
1760
1925
2100
1120
1260
1400
1540
1580
1765
1970
2100
–
1420
1595
1760
1920
1015
1160
1275
1390
1430
1625
1780
1890
NOTES
The effect of static pressure, filter and electric heater resistance is included in the air volumes listed.
First-stage cooling air volume is 70% of COOL (second-stage) speed setting. Continuous blower speed is approximately 50% of COOL speed setting.
Lennox Harmony III™ Zoning System applications minimum blower speed is 450 cfm.
Table 10. Merit
®
CBX25UHV, Thermostat and Single-Stage Outdoor Unit Operating Sequence
Operating Sequence
System Demand
System Response
System
Condition
Step
Thermostat Demand
Relative Humidity
Com
pressor
Air
Handler
CFM
(COOL)
Comments
Y1
Y2
O
G
W1
W2
Status
D
NO CALL FOR DEHUMIDIFICATION
Normal Operation
1
On
On
On
Acceptable
24 VAC
High
100%
Compressor and indoor air handler fol
low thermostat demand
BASIC MODE (only active on a Y1 thermostat demand)
Normal
Operation
1
On
On
On
Acceptable
24 VAC
High
100%
Thermostat energizes Y1 and de-ener
gizes D on a call for dehumidification
Dehumidification Call
2
On
On
On
Demand
0 VAC
High
60%/65
70%*
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation
1
On
On
On
Acceptable
24 VAC
High
100%
Dehumidification mode begins when hu
midity is greater than set point
Dehumidification Call
2
On
On
On
Demand
0 VAC
High
60%/65%
70%*
Dehumidification Call
ONLY
1
On
On
On
Demand
0 VAC
High
60%/65%
70%*
Thermostat will try to maintain room hu
midity setpoint by allowing the room
space to maintain a cooler room ther
mostat setpoint**
Jumpers at indoor unit with a single stage outdoor unit
With Condensing unit - Y1 to Y2 and R to O
With Heat Pump - Y1 to Y2
* During dehumidification, cooling air handler speed is as follows: 70% of COOL cfm for 018, 024, 030; 65% for 036; 60% for 042, 048 and 060 units.
** Thermostat will maintain the room temperature up to 2°F (1.2°C) cooler than the room thermostat setting in precision mode.