Install Instructions

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I-UBX-UBZ-UDX-UDZ (04-21) 1034344-0
CONTROLS—CONTINUED
Pressure Switch—Continued
• If a restriction or excessive flue length/turns cause the sensing pressure to be outside the pressure switch setpoint,
the switch will function to shut off the main burner. The main burner will remain off until the system has cooled
and/or the flue system resistance is reduced.
• Pressure switch settings are listed in Table 16.
Table 16. Pressure Switch Settings
UBX and UDX Models
Unit Size
Negative Pressure (IN WC)
Label Color
Startup Cold Equilibrium Hot Setpoint OFF Setpoint ON
030 1.20 0.90 0.30 0.45 Orange
045 (UBX) 1.00 0.80 0.25 0.40 Red
045 (UDX) 1.00 0.80 0.40 0.55 Green
060 0.90 0.80 0.35 0.50 Purple
075 0.80 0.70 0.45 0.60 Pink
100 0.90 0.70 0.50 0.65 Orange
125 1.40 1.00 0.70 0.85 Wine
150 0.70 0.60 0.35 0.50 Purple
175 0.80 0.70 0.40 0.55 Green
200, 225 2.30 1.60 1.10 1.30 Blue
250 2.70 1.80 1.10 1.30 Blue
300 2.50 1.90 1.10 1.30 Blue
350, 400 2.10 1.60 1.10 1.30 Blue
UBZ and UDZ Models
Unit Size
Differential Pressure (IN WC)
Label Color
Startup Cold Equilibrium Hot Setpoint OFF Setpoint ON
030 (UBZ) 1.20 0.90 0.30 0.45 Orange
030 (UDZ) 1.20 0.90 0.40 0.55 Green
045 (UBZ) 1.00 0.80 0.35 0.50 Purple
045 (UDZ) 1.00 0.80 0.40 0.55 Green
060 1.20 0.80 0.35 0.50 Purple
075 1.00 0.80 0.45 0.60 Pink
100 0.90 0.80 0.50 0.65 Orange
125 (UBZ) 1.30 1.00 0.70 0.85 Wine
125 (UDZ) 1.30 1.00 0.80 0.95 Gray
150 0.70 0.55 0.35 0.50 Purple
175 0.75 0.65 0.40 0.55 Green
200 2.60 1.80 1.10 1.30 Blue
225 2.50 1.60 1.10 1.30 Blue
250 2.60 1.80 1.10 1.30 Blue
300 (UBZ) 2.70 1.85 1.10 1.30 Blue
300 (UDZ) 2.70 1.85 1.30 1.50 White
350 2.25 1.80 1.50 1.70 Yellow
400 2.10 1.60 1.30 1.50 White