MCS MCS-8 User manual

MCS-8
HEAT PUMP MANUAL
Version 7
Revision 4.0
Software HPMP 7.00-U and greater
Supports MCS-STAT
The MCS Commitment
Our commitment is to provide practical solutions for the industries needs and to be both a leader and partner in the
effective use of microprocessor controls.
Micro Control Systems, Inc.
5400-1 Division Drive
Fort Myers, Florida 33905
[phone]
FAX: [phone]
www.mcscontrols.com
Information contained in this manual has been prepared by Micro Control Systems, Inc. and is company confidential and
copyright © protected 1996. Copying or distributing this document is prohibited.

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
1 Revision Page
Date Author Description of Changes
9/4/97 Kelly Mitchell Draft
5/1/98 Kelly Mitchell Updated manual for release version 1.0
5/12/98 R C Toney Update for Empire State Bldg. changes version1.1
7/15/98 R C Toney Minor corrections to the v1.1, control state summary and flow
diagram of the heat pump was added, changed to version 1.2
10/21/98 J G Walterick V7 update to generic, SI8/16, rearrange setpoints, new setpoints
8/28/00 Brian Walterick Revisions to make manuals for both heatpumps and chillers-
Labeled the manual Revision 2.0
02/02/01 Brian Walterick Updated manual for Modulating Hot Water Valve Heating Control
02/02/01 Brian Walterick Updated manual for Modulating Economizer Valve Control
07/15/02 R C Toney Updated manual reflects the new set points required for control
zone control. Cutin/cutout no longer supported. Software FHP
07.00-S and greater support changes. Manual labeled as Revision
2.2
7/28/03 SAK Updating Manual
09/10/04 RCT Communicating thermostat and all of its functions are now
supported in HPMP 7.00-U and greater software. The reheat
function has been separated from the heat function. PC-Config 32
bit version 1.69 or greater is required to support these new
functions.
09/24/04 RCT Added a modulating reheat function. PC-Config 32 bit version
1.70or greater is required to support these new functions.
2

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
2 Table of Contents
1 Revision Page.......................................................................................................................................2
2 Table of Contents .................................................................................................................................3
3 Introduction to the MCS-8 Heatpump / Chiller Controller..................................................................6
3.1 The MCS-8 Micro Controller:.....................................................................................................6
3.2 The MCS-8 will control the following items:.............................................................................7
3.3 Control will be based upon the following:..................................................................................7
4 Introduction to Control Modes and States............................................................................................8
4.1 CONTROL MODES...................................................................................................................8
4.1.1 FAN/PUMP ONLY MODE..................................................................................................................................8
4.1.2 COOLING MODE...............................................................................................................................................8
4.1.3 HEATING MODE................................................................................................................................................9
4.1.4 DEHUMIDIFICATION MODE............................................................................................................................9
4.2 CONTROL STATES ..................................................................................................................9
4.3 CONTROL STATUS DISPLAY (from the MCS-8 keypad) ...................................................10
4.4 CONTROL STATUS DISPLAY (from the PC-Conn Program)..............................................10
5 MCS-STAT Support...........................................................................................................................12
5.1.1 Wiring from the MCS-8.....................................................................................................................................12
5.1.2 Temperature sensor.........................................................................................................................................12
5.1.3 Humidity sensor................................................................................................................................................12
5.1.4 LCD Display......................................................................................................................................................12
5.1.5 LCD Alarms.......................................................................................................................................................12
5.1.6 Fan switch.........................................................................................................................................................14
5.1.7 Off/AUTO/SCHEDULED switch ......................................................................................................................14
5.1.8 Override button.................................................................................................................................................14
6 Heatpump / Chiller Control States:....................................................................................................15
5.1 BASE STATES.........................................................................................................................15
6.1.1 ‘HEATPUMP OFF’ state-.................................................................................................................................15
6.1.2 ‘FAN/PUMP ONLY’ state- (FAN/PUMP ONLY Control Mode)......................................................................15
6.2 COOLING’ states – (COOLING Control Mode) .....................................................................15
6.2.1 ECONO COOLING ..........................................................................................................................................16
6.2.2 COOL: 1 COMP................................................................................................................................................16
6.2.3 COOL: 2 COMPS.............................................................................................................................................16
6.2.4 COOL: 3 COMPS.............................................................................................................................................16
3

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
6.2.5 COOL: 4 COMPS.............................................................................................................................................17
6.3 HEATING’ states - (HEATING Control Mode).......................................................................17
6.3.1 ECON HEATING..............................................................................................................................................17
6.4 HEATING’ states - (type of heat is REVERSING VALVE) ...................................................18
6.4.1 HEAT: 1 COMP (type of heat is REVERSING VALVE).................................................................................18
6.4.2 HEAT: 2 COMPS (type of heat is REVERSING VALVE)..............................................................................18
6.4.3 HEAT: 3 COMPS (type of heat is REVERSING VALVE)..............................................................................18
6.4.4 HEAT: 4 COMPS (type of heat is REVERSING VALVE)..............................................................................19
6.5 HEATING’ states - (type of heat is HOT WATER VALVE) ..................................................19
6.5.1 HEAT-HOLDING (type of heat is HOT WATER VALVE) ..............................................................................19
6.5.2 HEAT-CLOSING (type of heat is HOT WATER VALVE)...............................................................................19
6.5.3 HEAT-OPENING (type of heat is HOT WATER VALVE)..............................................................................19
6.5.4 HEAT-SLOPE CL (type of heat is HOT WATER VALVE).............................................................................19
6.5.5 HEAT-SLOPE OP (type of heat is HOT WATER VALVE).............................................................................19
6.6 HEATING’ states - (type of heat is ELECTRIC HEAT)..........................................................20
6.6.1 ELECTRIC HEAT (type of heat is ELECTRIC HEAT) ...................................................................................20
6.7 DEHUMID states – (DEHUMIDIFICATION Control Mode).................................................20
6.7.1 DEHUM: 1 COMP ............................................................................................................................................20
6.7.2 DEHUM: 2 COMPS..........................................................................................................................................21
6.7.3 DEHUM: 3 COMPS..........................................................................................................................................21
6.7.4 DEHUM: 4 COMPS..........................................................................................................................................21
7 Reheat Options...................................................................................................................................23
7.1 None..........................................................................................................................................23
7.2 Hot Gas Reheat..........................................................................................................................23
7.3 Modulating Reheat only in dehumidification states..................................................................23
7.4 Electric Reheat ..........................................................................................................................23
7.5 Modulating Reheat in all states except HEATPUMP OFF or lock off states...........................23
8 MCS-8 States for Heatpump / Chiller Faults.....................................................................................25
8.1 LOCKOUT FAULT..................................................................................................................25
8.2 SAFETY FAULT......................................................................................................................25
8.3 SENSOR FAULT......................................................................................................................25
9 ECONOMIZER STATES..................................................................................................................26
9.1 BYPASSED-COOL..................................................................................................................26
7.2 BYPASSED-HEAT ..................................................................................................................26
7.3 ECONO OFF.............................................................................................................................26
4

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
9.4 ECONO COOL ON ..................................................................................................................26
9.5 ECONO HEAT ON...................................................................................................................26
9.6 NOT USED...............................................................................................................................26
10 SET POINTS AND DEFINITIONS: .................................................................................................27
11 Return Air Target Reset Logic...........................................................................................................32
12 AUTHORIZATION FUNCTION......................................................................................................33
13 The Micro Control Center Keypad Display Quick Reference ...........................................................34
14 The Micro Control Center Keypad Display Quick Reference-ENTRY KEYS....................................35
15 The Micro Control Center MCS-8 Quick Reference Sheet ...............................................................36
16 Details of MCS-8 Key Items..............................................................................................................37
17 Details of MCS-SI8/16 Key Items .....................................................................................................38
18 The MCS Sensors Quick Reference Sheet – Temperature, Supply Air, Humidity & Pressure
transducers .................................................................................................................................................39
19 The MCS Sensors Quick Reference Sheet - Dry Contact Inputs.......................................................40
20 The MCS Trouble Shooting Quick Reference Sheet .........................................................................41
21 Summary of Control States ................................................................................................................43
5

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
3 Introduction to the MCS-8 Heatpump / Chiller Controller
3.1 The MCS-8 Micro Controller:
The MCS-8 micro controller is designed to be the primary controller for a heatpump / chiller package. The MCS-8
control algorithm provides the ultimate in control strategies by enabling:
• The user to custom the controlling sensors in each of the four different modes,
• Establish targets and control zones that can be modified after a package has been commissioned,
• Eliminate service calls by:
• Take corrective action to prevent an alarm condition from occurring, and
• Automatically restarting a package following an alarm condition and not locking the package off
unless the same alarm has occurred twice with in a settable time period.
• Provide an easy to understand man-machine-interface by:
• Indicating the state of the system in English terms and
• Identifying in English terms all alarms and date/time stamping them.
The system design is modular and allows for one, two, three or four compressors. This is accomplished by coupling an
MCS-8 with either MCS I/O, RO-8 or SI-8 or SI-16 boards that provides the additional inputs that is required.
The system provides for:
• Optional economy stage for heating and or cooling,
• Complete dehumidification control and
• Standard heating and cooling control.
The user may select to have a single low pressure and a single high-pressure alarm input or specify individual low
pressure and individual high-pressure alarms by compressor. The user may also have digital low pressure and high-
pressure inputs or analog inputs. (Analog inputs provide actual suction and discharge pressure.)
The Windows based PC-Config program supports the flexibility of the control algorithm. The following is an example of
a water / air package using return air for the decisions in the fan / pump and dehumidification modes while using the
supply air input for decisions in the cooling and heating modes.
6

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
The following is an example of a package using zone air for all decisions. The zone temperature and humidity input can
be provided by MCS-STAT, communicating thermostat.
For additional flexibility the MCS-STAT is now supported with this software. This enables communication via the MCS-
STAT to be provided in the zone area.
3.2 The MCS-8 will control the following items:
• Blower motor(s) or pumps, (on/off plus speed control)
• Ball valve that directs flow through the economizer coil,
• Heatpump / chiller reversing valve(s),
• Compressors (up to 4),
• Hot gas reheat,
• Electric heating,
• Modulating reheat,
• Hot water heating and
• Alarm indicator.
3.3 Control will be based upon the following:
• Internal time clock that is battery backed up;
• Internal set points that can be adjusted with the proper authorization in a commissioned unit;
• Condenser water in & condenser water out;
• Return, Supply, Zone or Ambient air temperature;
• Return, Supply, Zone or Ambient air humidity;
• Run enable switch (digital input from the building management system), Network Run enable, or Run
enable from a MCS-STAT, communicating thermostat;
• System schedule override from the MCS-STAT, this is based upon the time in setpoint #20 when the
override button on the MCS-STAT is pushed and the system is not in an alarm mode.
• A series of safety indicators (some will require manual intervention while others will result in an automatic
restart when the condition is corrected).
7

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
4 Introduction to Control Modes and States
4.1 CONTROL MODES
The Control Mode dictates the general status of the unit and which Control States can be entered. There are four
modes and each mode has a unique control sensor and set points that are associated with that mode.
4.1.1 FAN/PUMP ONLY MODE
The FAN/PUMP ONLY STATE indicates this mode. It is in this mode that the system determines if any of the
other three modes should be entered. The other three modes; cooling, heating or dehumidification; will be
entered based upon set points 1 through 3: COOL ENABLE, HEAT ENABLE AND DEHD ENABLE.
Once the system is in one of the other three modes, its requirements must be satisfied and control returned to
the fan/pump only mode before any of the other modes can be entered.
In the example shown, the Return Air Sensor is the controlling sensor in this mode. If the Return Air is greater
than the cooling set point, the system will enter the Cooling Mode.
4.1.2 COOLING MODE
Once in this mode the system will develop a control-cooling zone based upon set points 4, 5 & 6. The system
will move through the cooling states to maintain the temperature within this control zone. Once the cooling
target has been satisfied, the system will return to the FAN/PUMP ONLY MODE.
In the example shown, the Supply Air Sensor is the controlling sensor in this mode. The system will step up
and down through all of the cooling states based upon the supply air temperature. Once the supply air cool
temperature target has been satisfied, the system will return to the FAN/PUMP ONLY MODE.
•Control
Control Zone +
Target
Control Zone-
8

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
4.1.3 HEATING MODE
Once in this mode the system will develop a control-heating zone based upon set points 10, 11 & 12. The
system will move through the heating states to maintain the temperature within this control zone. Once the
heating target has been satisfied, the system will return to the FAN/PUMP ONLY MODE.
The system will support three different types of heating:
1. Reversing Valve. The reversing valve will be turned on when in the heating mode and the
compressors will be staged on/off to maintain the temperature within the control-heating zone.
2. Hot Water Valve. The hot water valve will be modulated when in the heating mode to maintain the
temperature within the control-heating zone. Set points 46 through 54 will control the modulation of the valve.
3. Electric Heat. The relay output for the electric heat will be turned on when the control temperature is
below the control-heating zone. There can be only one stage of electric heat.
In the example shown, the Supply Air Sensor is the controlling sensor in this mode. The system will step up
and down through all of the heating states based upon the supply air temperature. Once the supply air heat
temperature target has been satisfied, the system will return to the FAN/PUMP ONLY MODE.
4.1.4 DEHUMIDIFICATION MODE
Once in this mode the system will develop a control dehumidification zone based upon set points 16, 17 & 18.
The control air will be cooled and reheated to dry out the air. The system will move through the
dehumidification states to maintain the humidity within this control zone. Once the humidity target has been
satisfied, the system will turn off the reheat and either return to the FAN/PUMP ONLY MODE if the control
temperature does not require cooling or to the first stage of cooling.
The reheat function is now specified independently from the heat options, refer to the section on reheat.
The Heat Type is Electric Heat, its associated RO is EL HEAT and the Reheat Type is Hot Gas its
associated RO is HGreheat.
In this mode the system is also checking to ensure that air temperature remains in the range created by the
values contained in set points #40,ALLOW DEHUMD, and #41, DISALW DHDIFF. If the temperature is not
with in this range, the system will immediately return to the FAN/PUMP ONLY MODE for further action. Note
the temperature sensor that is being checked is specified as the controlling sensor in the FAN/PUMP ONLY
MODE.
The set points values that are associated with each mode must be set based upon the control sensor that is used with
each mode.
4.2 CONTROL STATES
The MCS-8 controller is a state computer, that is, decisions are made based upon set points, timers and sensor inputs,
the controller moves from one state to another. The controller will change states to ensure the proper functioning of the
heatpump / chiller package.
Control States perform the following:
9

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
• Provides an easy to understand status of the system. For example, HEATPUMP OFF state indicates that
the system is off or the COOL: 1 COMP states indicates that the system is in the cooling mode and that
compressor 1 is on and providing cooling.
• Dictates, which relays (RO’S) will be on in a given state.
• Indicates how long the system has been in the current state.
• The system moves from one state to another in a fixed sequence with fixed rules.
This strategy is based upon providing target set points for heating, cooling and dehumidification. The system then
controls the heatpump / chiller capacity to maintain the target temperature. Set points that contain differential values are
used to calculate a control zone and the system will determine if more or less cooling, heating or dehumidification
capacity is needed to remain in this control zone.
The control states are divided into the following two groups:
• HEAT PUMP / CHILLER CONTROL STATES, these states deal with the status of the heat pump / chiller
system. They will indicate if the system is running and what action is being taken.
• ECONOMIZER CONTROL STATES, these states deal with the status of the economizer valve.
Control states, on the MCS-8, are displayed on the 2x16 LCD by depressing the SERVICE DIAGNOSTICS entry key
and then selecting the option CONTROL STATUS. (Depress the enter key.) The up and down arrow may then used to
scroll between the information screens. The control states can also be accessed via the PC-Conn program by selecting
‘STATUS’ from the button bar on the ‘SYS INF’ screen.
4.3 CONTROL STATUS DISPLAY (from the MCS-8 keypad)
The following will be displayed:
The FIRST SCREEN will display the HEAT PUMP / CHILLER CONTROL STATE and the time in that state.
Line 1)
Line 2) (time HH:MM:SS)
COOL: 2 COMPS
TIMER 1:26:06
The SECOND SCREEN will display by selecting with either the INCREASE or DECREASE key. This screen will
display the ECONOMIZER CONTROL STATE and the time in that state.
Line 1)
Line 2) (time HH:MM:SS)
ECON COOLING
TIMER 1:28:06
4.4 CONTROL STATUS DISPLAY (from the PC-Conn Program)
The status of both the HEAT PUMP / CHILLER STATES and ECONOMIZER STATES can also be viewed from the
PC-Conn program by accessing the STATUS button; in the lower right section of the status screen. The following will
be displayed:
1
0

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
11

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
5 MCS-STAT Support
One MCS-STAT is support in this software. It must be associated with the zone options.
5.1.1 Wiring from the MCS-8.
Communications between the MCS-8 and the communicating thermostat is provided via a four wire shielded
cable. This will provide the power and the RS485 communications. Two wires provide communications by
connecting the MCS I/O connector to the MCS-STAT. Make sure that the + terminal on the MCS-8 is
connected to the + on the MCS-STAT. The MCS-STAT requires 12 volts, this can be provided by connecting
the other two wires to the +12 volt and ground terminals on the MCS-8 and the MCS-STAT.
5.1.2 Temperature sensor.
• This is a temperature sensor with accuracy of ±0.1°F between 32°F and 99°F; it will provide the zone
temperature.
• This sensor display type must be STAT1F in the SI Info screen for the PC-Config.
• If used this must be in selected in the HT Pmp Info screen as the zone temperature.
5.1.3 Humidity sensor
• This is a humidity sensor with accuracy of ±0.2% between 0% and 100%; it will provide the zone humidity.
• This sensor display type must be STAT1% in the SI Info screen for the PC-Config.
• If used this must be in selected in the HT Pmp Info screen as the zone humidity.
5.1.4 LCD Display
• If the indicator is pointing to:
Actual: either the temperature which will be followed by an °F, e.g. 73.4°F, or the humidity, e.g. 45.7, will
be displayed. Either the up or down arrows will toggle between these two values.
Cool: The value of setpoint #4, COOL TARGET, will be displayed. This value can be changed with the up
and down arrows within the minimum and maximum range that is set for this setpoint. When the SET
button is pressed the new value will be transmitted to the MCS-8.
Heat: The value of setpoint #10, HEAT TARGET, will be displayed. This value can be changed with the up
and down arrows within the minimum and maximum range that is set for this setpoint. When the SET
button is pressed the new value will be transmitted to the MCS-8.
• If a alarm is active, an alarm number will be displayed on the MCS-STAT to indicate the alarm reason.
5.1.5 LCD Alarms
ALARM NAME DESCRIPTION # Displayed
INVALID CFG The configuration of the MCS-8 is
invalid or wrong type. The system
will not run.
1
INVALID CLOCK The hardware clock on the MCS-
8 has failed. Processing will
continue using the software
clock.
2
LOST MCS I/O An MCS I/O board is not
communicating. 3
MCS I/O OFF LINE An MCS I/O board has gone off
line. 4
EVAP OVRFLW1 An overflow on evaporator #1
has occurred. Refer to setpoint
#30.
5
1
2

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
EVAP OVRFLW2 An overflow on evaporator #2
has occurred. Refer to setpoint
#31.
6
DIG SAFETY A safety error condition has been
indicated. Refer to setpoint #32. 7
NO FLOW A no flow error condition has
been indicated. Refer to setpoint
#33.
8
COND FREEZE A condenser freeze condition has
been indicated. Refer to setpoint
#34.
9
EVAP FREEZE A evaporator freeze condition has
been indicated. Refer to setpoint
#35.
10
NOT USED 11
DIG LOCKOUT A lockout error condition has
been indicated. Refer to setpoint
#37.
12
NO AIR FLOW Air flow has been lost. Refer to
setpoint #38. 13
HI DISC PSI #1 A high pressure on compressor 1
has occurred. Refer to setpoint
#39
14
HI DISC PSI #2 A high pressure on compressor 2
has occurred. Refer to setpoint
#39
15
HI DISC PSI #3 A high pressure on compressor 3
has occurred. Refer to setpoint
#39
16
HI DISC PSI #4 A high pressure on compressor 4
has occurred. Refer to setpoint
#39
17
LOW SUCT PSI #1 A low pressure on compressor 1
has occurred. Refer to setpoint
#36
18
LOW SUCT PSI #2 A low pressure on compressor 2
has occurred. Refer to setpoint
#36
19
LOW SUCT PSI #3 A low pressure on compressor 3
has occurred. Refer to setpoint
#36
20
LOW SUCT PSI #4 A low pressure on compressor 4
has occurred. Refer to setpoint
#36
21
SENSOR FAILURE RTN TEMP The specified return temperature
sensor has failed. 22
SENSOR FAILURE RTN HUMID The specified return humidity
sensor has failed. 23
SENSOR FAILURE WATER OUT The specified water out sensor
has failed. 24
SENSOR FAILURE WATER IN The specified water in sensor has
failed. 25
SENSOR FAILURE COMP1 Either the high or low pressure
sensor for compressor 1 has
failed.
26
1
3

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
SENSOR FAILURE COMP2 Either the high or low pressure
sensor for compressor 2 has
failed.
27
SENSOR FAILURE COMP3 Either the high or low pressure
sensor for compressor 3 has
failed.
28
SENSOR FAILURE COMP4 Either the high or low pressure
sensor for compressor 4 has
failed.
29
NOT USED 30
NOT USED 31
5.1.6 Fan switch
• The fan switch indicates if the fan is to be on continuously, ON position or AUTO the system will control the
fan status.
• If used this sensor display type must be STAT1FN in the SI Info screen for the PC-Config.
5.1.7 Off/AUTO/SCHEDULED switch
• This switch indicates if the unit is in an off, auto or schedule mode.
OFF: will force the system to be off. This is in affect another run/stop switch to the MCS-8.
AUTO: will override the operating schedule making it always true.
SCHD: will allow the system to follow the operating schedule that is setup in the MCS-8.
• This sensor display type must be STAT1SY in the SI Info screen for the PC-Config.
5.1.8 Override button
• The override button performs the following functions:
If an alarm has occurred, the MCS-STAT horn will be on and the alarm light will be flashing.
- The first time that the button is pushed, the horn will be turned off but the alarm light will remain flashing.
- The second time that the button is pushed, the alarm light go off and a lockout reset message will be
transmitted to the MCS-8. This will perform the same action as if the lockout reset button on the MCS-8
was pushed.
If the system has no active alarms and the override button is pushed and the MCS-8 has the system off
due to the schedule being false; the schedule will be overridden for the time specified in setpoint #20. The
system will be enabled to run for this amount of time.
1
4

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
6 Heatpump / Chiller Control States:
The MCS-8 control algorithm will move from one state to another based upon set points, timers and sensor inputs. The
states and set points are defined in this document. The sophisticated control algorithm allows the controller to decide on
the number of heating, cooling or dehumidification stages based on one sensor while FAN/PUMP ONLY stage can be
controlled based on the same or a different sensor. (For instance: In the fan/pump mode the decision to cool, heat or
dehumidify could be based on return air while in the control of cooling and or heating modes the decision could be
based on supply air.) Refer to the section on CONTROL MODE. The system will develop cooling, heating and
dehumidification control zones and move through the various states to maintain the control air temperature or humidity
within those control zones.
5.1 BASE STATES
At startup the system will be in off state and when temperature and humidity conditions have been satisfied the system
will be in fan/pump only state.
6.1.1 ‘HEATPUMP OFF’ state-
When the system is powered up it will delay going into the normal operating mode based on the ‘STARTUP DLY’ set
point.
This state will also be entered if the RUN/STOP or NETWORK RUN/STOP switch is set to STOP or the MCS-STAT
system switch is set to OFF. Or if the RUN/STOP or NETWORK RUN/STOP switch is set to RUN and the MCS-STAT
system switch is set to SCHD and the operating schedule is false.
Once the startup delay time has expired the system and the system is enabled to run, the next state, FAN/PUMP
ONLY state, will be entered.
6.1.2 ‘FAN/PUMP ONLY’ state- (FAN/PUMP ONLY Control Mode)
When the system exits the HEATPUMP OFF state it will enter the FAN/PUMP ONLY state if either the operating
schedule is true or the RUN/STOP input is in run mode. (The RUN/STOP input is from a user input, usually the building
management system.) From this state the decision is made to go to heating, cooling, dehumidification or stay in the
‘FAN/PUMP ONLY’ state based on its controlling sensor. Examples of the set points for the ‘FAN/PUMP ONLY’ state
are shown below. These are based on using return air as the controlling sensor.
‘FAN/PUMP ONLY’ state –
Set Point # 1 ‘COOL ENABLE’ 75.0F
Set Point # 2 ‘HEAT ENABLE’ 68.0F
Set Point # 3 ‘DEHD ENABLE’ 55.0%
6.2 COOLING’ states – (COOLING Control Mode)
These states are entered from the ‘FAN/PUMP ONLY’ state. Examples of the set points for the COOLING state are
shown below, based on using supply air as the controlling sensor.
Cooling mode –
Set Point # 4 ‘COOL TARGET’ 50.0F
Set Point # 5 ‘COOL ZONE+’ 5.0F
Set Point # 6 ‘COOL ZONE- ’ - 5.0F
A cooling zone will be developed based upon the COOL TARGET and the COOL ZONE+ and the
COOL ZONE- set points. The system will add or remove cooling stages as needed to maintain the
temperature within the control cooling zone.
1
5

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
6.2.1 ECONO COOLING
This state is the economize mode and it will be entered if the controlling air temperature rises above the COOL
TARGET set point and the water temperature is below the COOL’G WATER set point. The valve that directs the water
flow will remain open in all cooling states as long as the water temperature is below the COOL’G WATER set point. The
ECONOMIZER STATES indicate the status of this valve. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the entering water is below the cold-water set point.
This state will be exited and the FAN ONLY state will be entered once the controlling air temperature has been
satisfied. If additional cooling is required, the system will move to the COMPRESSOR 1 COOLING stage. The system
will remain in the ECONO COOLING state for a minimum time as specified in the STEP DELAY set point unless the
water temperature is too warm to provide cooling, the system will immediately move to the COMP1 COOLING state.
6.2.2 COOL: 1 COMP
This state is the first stage of mechanical cooling and it will be entered if the controlling air temperature rises above this
stage’s set point. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is below the cool water set point.
• The reversing valve is on (cool state).
• Compressor one is turned on.
Once the controlling air temperature has been satisfied the ECONO COOLING state will be entered. If additional
cooling is required the system will move to COOL: 2 COMP. The system will remain in the COOL: 1 COMP state for a
minimum time as specified in the STEP DELAY set point.
6.2.3 COOL: 2 COMPS
This state is the second stage of mechanical cooling and it will be entered if an additional stage of cooling is needed to
keep the controlling air temperature within the control cool zone. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is below the cool water set point.
• The reversing valve is on (cool state).
• Compressor one is turned on.
• Compressor two is turned on.
Once the controlling air temperature has been satisfied the COOL: 1 COMP state will be entered. If additional cooling is
required the system will move to COOL: 3 COMP. The system will remain in the COOL: 2 COMP state for a minimum
time as specified in the STEP DELAY set point.
6.2.4 COOL: 3 COMPS
This state is the third stage of mechanical cooling and it will be entered if an additional stage of cooling is needed to
keep the controlling air temperature within the control cool zone. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is below the cool water set point.
• The reversing valve is on (cool state).
• Compressor one is turned on.
• Compressor two is turned on.
• Compressor three is turned on.
1
6

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
Once the controlling air temperature has been satisfied the COOL: 2 COMP state will be entered. If additional cooling is
required the system will move to COOL: 4 COMP. The system will remain in the COOL: 3 COMP state for a minimum
time as specified in the STEP DELAY set point.
6.2.5 COOL: 4 COMPS
This state is the fourth stage and final stage of mechanical cooling and it will be entered if an additional stage of cooling
is needed to keep the controlling air temperature within the control cool zone. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is below the cool water set point.
• The reversing valve is on (cool state).
• Compressor one is turned on.
• Compressor two is turned on.
• Compressor three is turned on.
• Compressor four is turned on.
Once the controlling air temperature has been satisfied the COOL: 3 COMP state will be entered. The system will
remain in the COOL: 4 COMP state for a minimum time as specified in the STEP DELAY set point.
6.3 HEATING’ states - (HEATING Control Mode)
These states are entered from the ‘FAN/PUMP ONLY’ state. Examples of the set points for the HEATING state
are shown below based on using supply air as the controlling sensor.
Heating mode –
Set Point # 10 ‘HEAT TARGET’ 70.0F
Set Point # 11 ‘HEAT ZONE+’ 1.0F
Set Point # 12 ‘HEAT ZONE-‘ -1.0F
A heating zone will be developed based upon the HEAT TARGET and the HEAT ZONE+ and
the HEAT ZONE- set points. The system will add or remove heating stages if type of heating is
reversing valve or if hot water the system will modulate the valve as needed to maintain the
temperature within the control heating zone. If the heating type is electric, the system will turn
on the electric heat relay when the temperature is below the control heating zone.
6.3.1 ECON HEATING
This state is the economize heating and it will be entered if the controlling air temperature falls below this stage’s
set point and the water temperature is above the HEAT’G WATER set point. The valve that directs the water
flow will remain open in all heating states as long as the water temperature is above the HEAT’G WATER set
point. The ECONOMIZER STATES indicate the status of this valve. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open, if the entering water is above the heating water set
point.
Economize heating is if available will be utilized by all three types of heating.
This state will be exited and the fan/pump only mode will be entered once the air temperature has been
satisfied. The system will remain in the ECONO HEATING state for a minimum time as specified in the STEP
DELAY set point unless the water temperature is too cool to provide heating and the controlling air temperature
is calling for additional heating.
1
7

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
6.4 HEATING’ states - (type of heat is REVERSING VALVE)
When the type of heat utilizes the reversing valve, the system will stage the compressors to maintain the control
temperature with in the control heat zone.
6.4.1 HEAT: 1 COMP (type of heat is REVERSING VALVE)
This state is the first stage of mechanical heating and it will be entered if the controlling air temperature falls
below this stage’s set point. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is above the heating water set
point.
• The reversing valve is off (heat state).
• Compressor one is turned on.
Once the controlling air temperature has been satisfied the system will move to the ECONO HEATING mode. If
additional heating is required, the system will move to the HEAT: 2 COMPS state. The system will remain in the
HEAT: 1 COMP state for a minimum time as specified in the STEP DELAY set point.
6.4.2 HEAT: 2 COMPS (type of heat is REVERSING VALVE)
This state is the second stage of mechanical heating and it will be entered if an additional stage of heating is
needed to keep the controlling air temperature within the control heat zone. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is above the heating water set
point.
• The reversing valve is off (heat state).
• Compressor one is turned on.
• Compressor two is turned on.
Once the controlling air temperature has been satisfied the system will move to the HEAT: 1 COMP mode. If
additional heating is required, the system will move to the HEAT: 1 COMPS state. The system will remain in the
HEAT: 2 COMPS state for a minimum time as specified in the STEP DELAY set point.
6.4.3 HEAT: 3 COMPS (type of heat is REVERSING VALVE)
This state is the third stage of mechanical heating and it will be entered if an additional stage of heating is
needed to keep the controlling air temperature within the control heat zone. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is above the heating water set
point.
• The reversing valve is off (heat state).
• Compressor one is turned on.
• Compressor two is turned on.
• Compressor three is turned on.
Once the controlling air temperature has been satisfied the system will move to the COMP2 HEATING mode. If
additional heating is required, the system will move to the COMP4 HEATING state. The system will remain in
the COMP3 HEATING state for a minimum time as specified in the STEP DELAY set point.
1
8

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
6.4.4 HEAT: 4 COMPS (type of heat is REVERSING VALVE)
This state is the fourth and final stage of mechanical heating and it will be entered if an additional stage of
heating is needed to keep the controlling air temperature within the control heat zone. In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is above the heating water set
point.
• The reversing valve is off (heat state).
• Compressor one is turned on.
• Compressor two is turned on.
• Compressor three is turned on.
• Compressor four is turned on.
Once the controlling air temperature has been satisfied the system will move to the HEAT: 3 COMPS mode.
The system will remain in the HEAT: 4 COMPS state for a minimum time as specified in the STEP DELAY set
point.
6.5 HEATING’ states - (type of heat is HOT WATER VALVE)
When the type of heat utilizes hot water, the system will modulate the hot water valve to maintain the control
temperature with in the control heat zone. The system determines if the control temperature is within, above or
below the control zone and the control temperatures rate of change. Based upon this information the system
determines if the hot water valve should be modulated and by what percentage. Refer to set points 46 through
54.
6.5.1 HEAT-HOLDING (type of heat is HOT WATER VALVE)
No change will be made to the hot water valve opening. The control temperature is being maintained.
6.5.2 HEAT-CLOSING (type of heat is HOT WATER VALVE)
The system will reduce the valve’s opening percentage. The control temperature is above the control zone and
the control temperature is not falling faster than allowed, based upon set point 53, HW MAX ROC-. If the valve
is completely closed, the system will move the to the FAN/PUMP ONLY state.
6.5.3 HEAT-OPENING (type of heat is HOT WATER VALVE)
The system will increase the valve’s opening percentage. The control temperature is below the control zone and
the control temperature is not increasing at a fast enough rate. The amount that the valve will be opened by will
be calculated based upon where the temperature is in relationship to the heat target.
6.5.4 HEAT-SLOPE CL (type of heat is HOT WATER VALVE)
The system will reduce the valve’s opening percentage. The control temperature is moving toward the heat
target too fast. If the control temperature is within the control zone, the valve percentage open will be reduced by
the value in set point 48, HW MIN ADJ%. If the temperature is outside of the control zone, the amount that the
valve will be closed by will be calculated based upon where the temperature is in relationship to the heat target.
6.5.5 HEAT-SLOPE OP (type of heat is HOT WATER VALVE)
The system will increase the valve’s opening percentage. The control temperature is moving is not moving
toward the heat target. If the control temperature is within the control zone, the valve percentage open will be
increased by the value in set point 48, HW MIN ADJ%. If the temperature is outside of the control zone, the
amount that the valve will be opened by will be calculated based upon where the temperature is in relationship
to the heat target.
1
9

Heatpump Water-Air/Water-Water Heatpump/Chillers MCS-8 Version 7 Manual Revision 4.0
6.6 HEATING’ states - (type of heat is ELECTRIC HEAT)
If type of heating is electric, this is only one stage of heating. It is either on if heat is required or off.
6.6.1 ELECTRIC HEAT (type of heat is ELECTRIC HEAT)
The system will turn on the electric heat when the control temperature is below the control heat zone. The
electric heat will remain on until the control temperature is above the control heat zone.
6.7 DEHUMID states – (DEHUMIDIFICATION Control Mode)
These states are entered from the ‘FAN/PUMP ONLY’ state. Examples of the set points for the DEHUMID state
are shown below based on using return air as the controlling sensor.
Dehumidification mode –
Set Point # 16 ‘DEHD TARGET’ 55.0%
Set Point # 17 ‘DEHUM ZONE+’ 5.0%
Set Point # 18 ‘DEHUM ZONE- ‘ -5.0%
A dehumidification zone will be developed based upon the DEHD TARGET and the DEHUM
ZONE+ and the DEHUM ZONE- set points. The system will add or remove dehumidification
stages as needed to maintain the humidity within the control dehumidification zone.
REFER TO THE REHEAT OPTIONS SECTION.
Note: The ECONO COOLING is enabled during dehumidification if the water temperature is below the ECON
CL ON set point #28. The valve that directs the water flow will remain open in all dehumidification stages as long
as the water temperature remains below this set point
6.7.1 DEHUM: 1 COMP
This state can only be entered if the system is in the FAN/PUMP ONLY state. This state is entered when the
controlling air humidity (usually return or zone humidity) rises above the control dehumidification zone and the
controlling air temperature is below the allow dehumidification set point. If the controlling air temperature is
above the cooling setpoint the system will enter COOLING. (COOLING has priority since we want to take
out moisture but don’t want the reheat on.) In this state:
• The blower motor(s) is on.
• The valve that directs the water flow is open if the water temperature is below the cool water set
point.
• The reversing valve is on (cool state).
• Compressor one is turned on.
• Enable reheat.
When the controlling air humidity drops below the control dehumidification zone or the controlling air
temperature is above the disallow dehumidification set point calculation, the system will return to the
FAN/PUMP ONLY state. The system will remain in the DEHUM: 1 COMP state for a minimum time as specified
in the STEP DELAY set point unless the controlling air temperature is above the disallow dehumidification set
point calculation.
2
0