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The performance specifications are nominal and conform to acceptable industry standards. For applications at conditions beyond these specifications, consult the local Johnson Controls office.
Johnson Controls, Inc. shall not be liable for damages resulting from misapplication or misuse of its products. © 2015 Johnson Controls, Inc. www.johnsoncontrols.com
R-88
P29 Series Low Pressure Control with Time Delay
Description
P29NC is a low pressure control with time
delay and lockout, which requires manual
reset. A drop in pressure energizes the time
delay relay and opens a contact after the time
delay, shutting down the equipment. The time
delay prevents nuisance shutdowns due to
momentary fluctuations in system pressures.
Refer to the P29 Series Low Pressure Cutout
Control with Time Delay Relay Product Bulletin
(LIT-125425) for important product application
information.
Features
• direct reading scale indication
• dust-protected snap action switch
• trip-free manual reset
• replacement timing relays available
Applications
• chiller low temperature
• industrial equipment, oil pressure
lubrication
• low suction pressure
Technical Specifications
• pilot duty rating of 750 VA, 120/240 VAC
• external step down transformer for 440 and
550 VAC applications must be of sufficient
capacity to supply 15 VA at 120 VAC or
30 VA at 240 VAC for time delay
Accessories
• universal mounting bracket (271-51)
• replacement timing relays (Refer to
Replacement Timing Relays for P28 and
P29 Lube Oil Controls Catalog Page
[LIT-1927395].)
Selection Chart
Example: Setpoint at 10 psig. On a rise in pressure, the timing circuit opens at 10 psig and time out ends. On a fall in pressure, the timing
circuit energizes at 6 to 9 psig and the time out begins. If the pressure fails to reach 10 psig within the 60 second time delay, the main contacts
open, shutting down the controlled equipment.
Product Code
Number
Switch
Action
Pressure
Range
Differential
psi (kPa)
Max Overpressure
psig (kPa)
Max Working Pressure
psig (kPa)
Pressure
Connection
Time Delay
Setting
P29NC-2C Single-Pole,
Single-Throw
(SPST)
20 in. Hg Vacuum
to 100 psig
(-68 to 690 kPa)
2.2 ±1.5
(15.2 ±10.3)
325
(2,241)
250
(1,723)
1/4 in. external
flare fitting
60 seconds
(factory set)
P29NC-3C 36 in. copper
capillary tube
with 1/4 in. flare nut
P29NC-49C 120 seconds
P29NC-53C 90 seconds
P29NF-1C
1
1. With alarm contacts
120 seconds
P29 Series Low Pressure Control
Standard Electromechanical Pressure Controls
Code No. LIT-1927190
Repair Information
If the P29 Series Low Pressure Control with
Time Delay fails to operate within its
specifications, replace the unit. For a
replacement control, contact the nearest
Johnson
Controls® representative.