These oil protection controls are designed to give protection against low net lube oil pressure on pressure lubricated refrigeration compressors. The controls measure the pressure differential between the pressure generated by the oil pump and the refrigerant pressure at the crankcase. A built in time delay switch allows for pressure pick up on start and avoids nuisance shutdowns on pressure drops of short duration during the running cycle. Features and Benefits • Heavy duty pressure elements Withstand high overrun pressure • Safety lock-out with trip-free manual reset Override is not possible in the control function • Ambient compensated timing Stable delay time during all ambient conditions • Dust-tight Penn switch Prevents pollution of the contacts by electrostatic influences PB_P28_09 2018 P28 Oil Protection Controls Product BulletinDimensions (in mm) Type P28DA-DP A Mounting hole, 5 mm dia. B (2) mounting bracket holes, 10-32 UNF C Mounting slot D Cable inlet hole, 22.3 mm dia. R Reset button Type P28DJ A(4) MTG holes, 7 mm dia. BConnector, PG 16 C1/4"-18 NPT (2x) A C B 193 Ø 44 36 53 70 180160 148 41 40 92 72 43 123 107 8021 52 8 32 8 53 7 6 241.5 1 4 4 2082 5 3 32 17 25 1 2 7 10 3 9 29 32 3 3 R D A C B PB_P28_09 2018 2PB_P28_09 2018 3 Description When the compressor is started, the time delay switch is energised. If the net oil pressure does not build up within the required time limit, the time delay switch trips to stop the compressor. If the net oil pressure rises within the required time after the compressor starts, the time delay switch is automatically de energised and the compressor continues to operate normally. If the net oil pressure should drop below setting (scale pointer) during the running cycle, the time delay switch is energised and, unless the net oil pressure returns to cut in point within the time delay period, the compressor will be shut down, and have to be manual reset. The compressor can never run longer than the predetermined time on low oil pressure. Controls are available only for manual reset after cut-out. These controls are designed for use only as operating controls. Where an operating control failure would result in personal injury or loss of property it is the responsibility of the installer to add devices or systems that protect against, or warn of, control failure. Time Delay Switch Timings of 30, 50, 90 or 120 seconds are available for all models. The 230 VAC time delay circuit requires 30 VA for timing of 120 seconds and 50 VA for timing of 30 seconds. The time delay unit is compensated to assure uniform timing for 0 to 55°C ambient temperature. Timing is affected only by voltage variations. After a lock-out has occurred the control can be manual reset after the time delay switch has cooled down for minimum 15 minutes. Time Delay Heater Circuits Standard controls are equipped with time delay circuit for 230 VAC. Special models can be supplied at extra cost for 12 V AC/DC, 24 V AC/DC or 115/230 V AC. Quantity orders only. P28DA Control, Cover removed (P) Setpoint adjusting cam Repair and Replacement The timer and terminal board assembly may be replaced as a complete unit. Other repairs are not recommended. When contacting the supplier for a replacement you should state the type/modelnumber of the control. This number can be found on the data plate or cover label.PB_P28_09 2018 4 Typical Wiring Diagrams M P > 230LMA 2 1 3 L P HP 115 O R S T 4 5 2 3 1 P28DA M P > 230L MA 2 1 3 L P HP O R S T 4 5 2 3 1 P28DP/DJ * M L M A P > 2 1 3 O R S T 3 x 380 V 12 or 24 V LP HP 4 6 2 5 3 1 7 12 or 24 VAC or VDC • Electro magnetic switch • Operating control • Alarm light • Safe light • Additional controls only in this line • Jumper • Transformer (12 or 24 V) “LP” = LP bellows “HP” = HP bellowsPB_P28_09 2018 5 Type Number Selection Table Order Number Pressure connectionTiming (s)VoltageRefrigerantRemarks P28DA-9341550115/230non-corrosiveincl 2 flare nuts 7/16"-20 UNF P28DA-96601390115/230non-corrosive P28DJ-9360590230non-corrosive P28DJ-98611590230NH3 P28DP-93005-230non-corrosivewithout time delay P28DP-9340550230non-corrosive P28DP-9360590230non-corrosive P28DP-93805120230non-corrosive P28DP-96401350230non-corrosive P28DP-96601390230non-corrosive P28DP-968013120230non-corrosive P28DP-98401550230NH3 P28DP-98601590230NH3 Pressure Connections 21 Style 5 Male connection 7/16"-20 UNF for 1/4" /6 mm flare nut Style 13 1. 90 cm capillary 2. 7/16"-20 UNF nut for 1/4" SAE flare tube Style 15 1/4"-18 NPT (female) Accessories Mounting Bracket90 cm Capillary with (2) flare nuts Compression CouplingPB_P28_09 2018 www.johnsoncontrols.com Building Efficiency Headquarters: Milwaukee, Wisconsin, USA Branch Officies: Principal Cities World-wide Johnson Controls® is registered trademarks of Johnson Controls. All other marks herein are the marks of their respective owners. © Copyright 2018 Johnson Controls. All rights reserved. Any unauthorized use or copying is strictly prohibited. Accessories Ordering Codes CodesDescriptionApplication CNR003N001R Compression coupling fits into Style 15 pressure connection For 6 mm copper or steel tubing CNR003N002RFor 8 mm copper or steel tubing 271-51LMounting Bracket SEC002N60090 cm capillary with two flare nuts Technical Specifications ProductsP28DAP28DJP28DP Dual voltage 115/230 V Single voltage 230 V ApplicationOil protection control on refrigeration compressors Pressure ConnectorsStyle 5, 15, 13 (see drawings) Operating Range * 0.6 to 4.8 bar Operating at pressures greater than 17 bar may lead to bellows failure and catastrophic refrigerant loss Maximum Allowable Overrun Pressure23 bar Range AdjustmentTurn range cam to reach set point desired Material CaseGalvanized steel CoverGrey coloured galvanized steel Enclosure IP30IP66IP30 Electrical Ratings15(8) A, 230 VAC Shipping Weight Ind. pack1.5 Kg3 Kg1.5 Kg Overpack15 Kg (10 pcs)12 Kg (4 pcs)15 Kg (10 pcs) Compliance Johnson Controls declares that these products are in compliance with the essential requirements and other relevant provisions of the EMC Directive 2014/30/EU and Low Voltage Directive 2014/35/EU. RoHS Directive 2011/65/EU * Time delay de energised at 0.21 to 0.34 bar pressure difference above setting 100 kPa = 0.1 MPa = 1 bar ≈ 1.02 kp/cm 2 = 1.02 at ≈ 14.5 psi The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond these specifications, consult the local Johnson Controls office. Johnson Controls shall not be liable for damages resulting from misapplication or misuse of its products.Next >