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Two Condenser Head Pressure II Module Technical Guide

10

SEQUENCE OF OPERATION

VCM-X Input Commands and Modes of Operation

Input Commands (VCM-X Connection)

Condenser A & B On/Off 

Instead of a hard wired input signal to the Condenser Enable 

input, the VCM-X Modular Controller, VCM-X WSHP 

Controller, or SA Controller communicates to the Module via 

E-BUS communications. This signal indicates the compressor(s) 

are called to run and drives the condenser A & B On/Off function.

Reversing Valve Enable A & B On/Off 

As with the Condenser Signal On/Off function, the VCM-X 

Modular Controller, VCM-X WSHP Controller, or SA Controller 

communicates to the Module via E-BUS communications and 

signals that the reversing valve has been energized and that 

heating has been enabled.

NOTE:

   

When the term “ON” is used, it means there is 

either 24 VAC on the appropriate Binary Input 

or a call-to-run signal is being received from a 

VCM-X series or SA series controller. When the 

term “OFF” is used, it means there is either 0 

VAC on the appropriate Binary Input or the call-

to-run signal from a VCM-X series or SA series 

controller has been removed.

Sensor Reading Routine

The Two Condenser Head Pressure Module is used on units 

with two physically separate condenser sections. Up to (2) Head 

Pressure Sensors can be monitored in each section. The highest 

of the two readings in each section will be used to control the 

condenser fan(s) in that section.

Air from the condenser fan(s) in each section flows through both 

condenser coils. As a result, if you modulate the fan(s) based on 

the highest reading, you will have enough air flow for both coils.

The highest reading of Head Pressure Sensors 1 & 2 controls 

Condenser Fan A. The highest reading of Head Pressure Sensors 

3 & 4 controls Condenser Fan B. 

Modes of Operation

OFF Mode

The Head Pressure Control Board is in the OFF Mode when the 

Condenser Input Signals are “OFF.”  In this mode, all relays are 

off, the Analog Output is 0 VDC, and the PWM Output is 0% 

Duty Cycle. 

Cooling Mode

If the Head Pressure Controller has been configured for the 

Reversing Valve to be energized in the Cooling Mode and to Fail 

to the Heat Mode (Dipswitch 4 is set ON), then the Head Pressure 

Controller will be in the Cooling Mode when one or both of the 

Condenser Signal inputs is “ON” and the Reversing Valve Enable 

Signal is “ON”.  In this circumstance, the Reversing Valve Enable 

Relay Output(s) will energize for indication purposes.

If the Head Pressure Controller has been configured for the 

Reversing Valve to be energized in the Heating Mode and to 

Fail to the Cool Mode (Dipswitch 4 is set OFF), then the Head 

Pressure Controller will be in the Cooling Mode when one or 

both of the Condenser Signal inputs is “ON” and the Reversing 

Valve Enable Signal is “OFF”. 

The Condenser Enable Relays will energize to enable the 

Condenser Fans or Water Valves. In a water system, the Water 

Flow Valve will start at 75% for 3 minutes. The Condenser Output 

Signals will then automatically adjust between 0 and 100% to 

maintain the desired Head Pressure Setpoint. The Condenser 

Output Signals can be a 0-10 VDC, 2-10 VDC or 0-100% PWM 

signal provided by the appropriate output.  Both outputs mirror 

each other.  

Heating Mode

If the Head Pressure Controller has been configured for the 

Reversing Valve to be energized in the Cooling Mode and to 

Fail to the Heat Mode (Dipswitch 4 is set ON), then the Head 

Pressure Controller will be in the Heating Mode when one or 

both of the Condenser Signal inputs is “ON” and the Reversing 

Valve Enable Signal is “OFF”. 

If the Head Pressure Controller has been configured for the 

Reversing Valve to be energized in the Heating Mode and to 

Fail to the Cool Mode (Dipswitch 4 is set OFF), then the Head 

Pressure Controller will be in the Cooling Mode when one or both 

of the Condenser Signal inputs is “ON” and the Reversing Valve 

Enable Signal is “ON”. In this circumstance, the Reversing Valve 

Enable Relay Output(s) will energize for indication purposes.

In this mode, the Condenser Output Signals will go to 100% and 

remain there until it leaves the Heating Mode.

NOTE: 

The Reversing Valve Dipswitch 4 setting 

determines whether the Reversing Valve Dipswitch 

4 Relay is ON to Heat / OFF to Cool or ON to  

Cool / OFF to Heat.

NOTE:

   

The Reversing Valve Enable outputs are for 

indication only and are not wired to anything.

Содержание ASM01891

Страница 1: ...Two Condenser Head Pressure II Module Technical Guide ...

Страница 2: ... N V22100 Rev F Copyright September 1 2022 AAON Inc AAON is a registered trademark of AAON Inc Tulsa OK AAON assumes no responsibility for errors or omissions in this document This document is subject to change without notice HP2C2 REVISION LOG REVISION AND DATE CHANGE Rev E April 1 2015 previous version Rev F September 1 2022 added note the HSSC cable is no longer supplied with this module update...

Страница 3: ...II Module Wiring 7 E BUS Controller to Two Condenser Head Pressure II Module Wiring 8 Stand Alone Input Commands 9 SEQUENCE OF OPERATION 9 VCM X Input Commands and Modes of Operation 10 OPTIONS Dip Switch Settings 11 OPTIONS Dip Switch Settings 12 Head Pressure Module Valve Fan Position Troubleshooting 13 TROUBLESHOOTING 13 Troubleshooting for Stand Alone Mode 14 Pressure Transducer Troubleshootin...

Страница 4: ...d alone or up to two modules can be daisy chained together and connected to a VCM X Modular E BUS VCM X WSHPE BUS or SAE BUS Controller Monitors up to four individual head pressure transducers Provides control of Condenser Output Signals based on the highest reading of head pressure transducers Capable of monitoring a Reverse Valve Signal Forces Condenser Fans to 100 while in the Heat Pump Heating...

Страница 5: ...cer 3 When the Analog Output is being used to control the Condenser Fan Speed or Water Valve Percentage the cable must be 18 gauge shielded wire and the Drain Wire must be the Gnd signal 4 If the Pulse Width Modulation PWM Output is being used to directly control the ECM 142 motor the wires do not need to be shielded and can be any 18 gauge wire 5 04 5 64 5 71 2 07 0 55 4 14 0 29 0 18 DIA TYP ALAR...

Страница 6: ...M Condenser Signal A CONDENSER A ENABLE R1 HVAC UNIT CONNECTION R3 CONDENSER B ENABLE NOTE NORMALLY OPEN AND RATED FOR 24 VAC POWER ONLY ALL RELAY OUTPUTS ARE 1 AMP MAXIMUM LOAD COMM Set ADDRESS Dip Switch 1 to ON for Water Cooled or to OFF for Air Cooled Currently showing OFF for Air Cooled ADDRESS Dip Switch 2 is not used in this application Set ADDRESS Dip Switch 3 to ON to disable Circuit B al...

Страница 7: ...RESS Dip Switch 2 to OFF on all communicating applications unless it is intended to be the Second Head Pressure Module on a system If set to ON it will not communicate Set ADDRESS Dip Switch 3 to ON to disable Circuit B alarms when only one Condenser is Used Currently showing OFF Set ADDRESS Dip Switch 4 to OFF to make reversing valve ON to Heat OFF to Cool Set to ON to make reversing valve ON to ...

Страница 8: ...al CO Sensor 2 Warning 24 VAC Must Be Connected So That All Ground Wires Remain Common Failure To Do So Will Result In Damage To The Controllers T to T R to R SHLD to SHLD Size Transformer For Correct Total Load VCM X Controller 8 VA OE332 23E VCMX MOD VCM X Modular E BUS Controller Note All Relay Outputs Are Normally Open And Rated For 24 VAC Power Only 1 Amp Maximum Load AI1 SET AI2 SET AI3 SET ...

Страница 9: ...ng Dip Switch values NOTE The only setpoint available for adjustment by the contractor is the Head Pressure Setpoint The rest of the setpoints described can only be changed by the factory ADDRESS Dip Switch Settings for Condenser Type Selection When using the OPTIONS Dip Switch to set the Head Pressure Setpoint you must also set the ADDRESS Dip Switch to designate the type of condenser you are usi...

Страница 10: ...for the Reversing Valve to be energized in the Cooling Mode and to Fail to the Heat Mode Dipswitch 4 is set ON then the Head Pressure Controller will be in the Cooling Mode when one or both of the Condenser Signal inputs is ON and the Reversing Valve Enable Signal is ON In this circumstance the Reversing Valve Enable Relay Output s will energize for indication purposes If the Head Pressure Control...

Страница 11: ...5 DEFAULT 1 260 210 2 270 220 3 280 230 4 290 240 5 300 250 6 310 260 7 320 270 8 330 280 9 340 290 10 350 300 11 360 310 12 370 320 13 380 330 14 390 340 15 400 350 ADDRESS Dip Switch 1 Settings Switch 1 Default SP Description of Default Head Pressure Setpoint OFF 340 Air Cooled Condenser using R410 A Refrigerant ON 235 Water Cooled Condenser using R410 A Refrigerant Switch 1 determines Air or Wa...

Страница 12: ...ngs ADDRESS Dip Switch 4 Settings Switch 4 Description OFF Reversing Valve On to Heat Off to Cool ON Reversing Valve On to Cool Off to Heat Table 6 ADDRESS Dip Switch 4 Settings for Reversing Valve ADDRESS Dip Switch 2 Settings Switch 2 Description OFF Set to OFF if Using only 1 Head Pressure Module or if this is Module 1 when Using 2 Head Pressure Modules ON Set to ON if this is Module 2 when Usi...

Страница 13: ...ximum fan speed is 10 volts 100 Anything less than 1 5 volts the fan will be off PWM signal is 0 to 100 PWM to ground will always read 24 vdc PWM to ground can be measured for volts dc and this formula will tell you the percentage signal 24 measured value 24 measured value PWM to ground PWM 0 volts 100 fan speed 6 volts 75 fan speed 12 volts 50 fan speed 18 volts 25 fan speed 20 4 volts 15 fan spe...

Страница 14: ...Max Voltage of 10VDC See Sequence Higher Monitor DC Volts on A ut 1 2 Voltage O should Modulate Down to a Min voltage of 0VDC See Sequence Lower There will be No Change on A ut 1 O 2 Same 1 Blink None of the Sensors are Check wiring on all sensors Measure DC Volts between SIGx GND for all sensors Compare readings to chart Yes 2 Blinks High Pressure on one of the Sensors More than 500 PSI 3 Blinks ...

Страница 15: ...mmunication one for alarms and four for compressor relays See Figure 6 for the LED locations The LEDs associated with these inputs and outputs allow you to see what is active without using a voltmeter Status LEDs COMM This LED will light up to indicate Communications with theVCM X series or SAseries controller If Communications are established the COMM LED will blink You should not see this LED li...

Страница 16: ...these checks the PWR LED does not light up the module is probably defective COMM LED When the Two Condenser Head Pressure II Module is powered up while in Stand Alone Mode the COMM LED does not light up When the module is connected to a VCM X series or SA series controller the COMM LED should light up indicating Communications Each time Communications are detected this LED should continuously blin...

Страница 17: ...Controls Support 866 918 1100 Monday through Friday 7 00 AM to 5 00 PM Central Standard Time Controls Support website www aaon com aaon controls technical support AAON Factory Technical Support 918 382 6450 techsupport aaon com NOTE Before calling Technical Support please have the model and serial number of the unit available PARTS For replacement parts please contact your local AAON Representativ...

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