NR-1 Single Stage Control – Service Manual.
Introduction 3
Connecting the NR-1 3
NC-4 Thermostat 3
External 24VAC Thermostat 4
User Interface 5
Resetting the NR-1 5
Power-Up Sequence 5
Normal Display Mode 6
Start delay 6
Speed Up 7
Dirty filter 7
External System Disable 8
External After-Hours Override 8
Indoor Fan 9
Automatic 9
Continuous Fan 9
Indoor Fan During Defrost 9
Loss of FAN(G) input 9
Cooling Operation 10
Heating Operation 10
Defrost 11
The Outdoor Fan 12
Reversing Valve 13
LP Bypass 13
Heating 13
Defrost 13
Installer And Service Parameters 13
Acessing Installer Parameters 14
Accessing Service Parameters 14
Setting Parameters 14
Restoring Parameters To Default 15
Status Menu 16
Viewing Temperature Sensors 16
Manually Controlling The Outdoor Fan 16
Fault Handling 17
Accessing The Error Log 17
Clearing The Error Log 19
Resetting Faults 19
Common Fault Output 19
Defrost and ambient temperature sensors 20
HP / LP open circuit and LP-Bypass failure 20
Compressor and outdoor fan overload option 21
Indoor fan overload option 22
Phase failure option 22
24Vac failure 22
NR-1 Internal Error 23
Error List 24
Parameter List 25
Installer Parameters 25
Service Parameters 26
Introduction
The NR-1 is an intelligent electronic control for single stage, reverse cycle air-conditioning systems. It has the following features:
§ Support for multiple NC-4 thermostats
§ Support for standard 24VAC thermostats
§ Two speed outdoor fan for reduced noise during low load conditions
§ Ambient and defrost (outdoor coil) temperature sensors
§ HP / LP fault detection with automatic retry
§ Dual 7-segment display for the status and fault indication
§ 3 push buttons for configuring the control
§ 24Vac input for disabling the system from an external source such as a time clock or building management system.
§ Voltage free fault output to notify external systems of a problem.
§ 24Vac momentary input for external after-hours run-on. (Only available when used in conjunction with NC-4)
§ Up to eight fault conditions can be stored in memory for later retrieval by qualified service personal
§ The following additional OPTIONS may added to the NR-1
o Detection of up to four additional fault conditions which include indoor fan overload, outdoor fan overload, compressor overload and phase failure.
o Auxiliary heat output which can be configured to operate during defrost and high-demand situations. The 516 Add-on board is required for this feature (CURRENTLY NOT AVAILABLE)
o Heat output terminal. The 516 Add-on board is required for this feature (CURRENTLY NOT AVAILABLE)
Connecting the NR-1
NC-4 Thermostat
An NC-4 Thermostat may be used in conjunction with the NR-1 to provide a number of additional features which include:
§ Multiple NC-4 Thermostats on one system
§ Auxiliary heating. The 516 Add-on board is required for this feature (CURRENTLY NOT AVAILABLE)
§ Display of NR-1 fault conditions via the NC-4 display
§ Easy configuration of the NR-1 via the NC-4
§ After-hours run-on timer for commercial applications
The connection between the NR-1 and NC-4 is known as the Two Wire Bus (TWB). The TWB only requires 2-core unshielded cable to communicate and provide power to the NC-4.
WARNING: Under no circumstances should any device, other than the NC-4 be connected to the TWB.
Below is an example of how a single NC-4 is connected to the NR-1
It is possible to add a second NC-4, enabling control of the system from two locations. A typical application would be a two-story building with one NC-4 upstairs and the other downstairs.
External 24VAC Thermostat
Any standard thermostat or building management system can control the NR-1. This is accomplished by connecting the 24VAC (R) stat terminal to the appropriate input. See below.
User Interface
The NR-1 user interface consists of 3 push buttons and a dual 7-segment display, which provides the following capabilities:
§ Display the normal operating state
§ Display of fault conditions if they exists
§ Provide diagnostic information
§ Enable the user to configure the control by setting various parameters
§ Enable ‘Speed-Up’ and override the ‘Start Delay’ for service personal
§ Reset the control
There are three user push buttons, UP, DOWN and SET, to navigate the system.
When power is first applied or a reset has been performed, the NR-1 will perform its normal boot-up sequence. This includes initialising hardware and software, checking the integrity of the non-volatile memory and allowing the system to stabilise before performing any functions.
Resetting the NR-1
Pressing UP+DOWN+SET will reset the NR-1. Where possible, this method of resetting the control should be used instead of cycling the power.
Power-Up Sequence
The following sequence is displayed when the NR-1 is first powered.
8.8. / Power upnr-1 / Name of the control
rX / Revision of the firmware. The current revision number replaces the X).
Note. After the above sequence is complete, the system start delay will be shown. See the section on “Speed Up”.
Normal Display Mode
When no menus are being accessed, the display remains in ‘Normal’ mode. In this mode the following can be displayed depending on the status of the system.
oFF / System is OFFFAn / Indoor fan is operating
rE / rd / ‘rE’ indicates the R-valve is energised and ‘rd’ means system is still in heat mode, but valve has been de-energised cause the compressor has been off for more than 120 minutes.
Cool / The system is cooling
HEAt / The system is heating
LP-bi / The LP bypass is active
AuH / Auxiliary heat is operating
Hi / The outdoor fan is operating at high speed
Lo / The outdoor fan is operating at low speed
FiLt / A filter change is required
SPEEd / The system is in speed-up
Er -- / ‘Er’ followed by a number, indicates the current error
DELAy / The 5 minute compressor cycle delay is running
E-oFF / There is an external system OFF (AUX A input)
dEF / The system is in defrost
noFan / No call for indoor FAN(G) input was detected 10 seconds after the COMP(Y) call OR the FAN(G) was cleared before COMP(Y).
Start delay
When the NR-1 is first powered and it completes the start-up sequence, it is subject to a start delay. The default start up delay is 2 minutes, which commences from power-up. The remaining time is displayed after the ‘start-up’ sequence has completed. If the time is greater than 99 seconds, the display will only show the remaining time in minutes. 99 seconds and below, the display will show seconds.
The start up time may be changed from 0 to 255 seconds using the following parameter.
System Start Delay
Type / ID / Default / Min. / Max. / Scaling / UnitsInstaller / 3 / 120 / 0 / 255 / 1 / Seconds
The delay may be overridden by pressing the UP button during the start delay.
Speed Up
To assist installation and service, the NR-1 can be put into Speed Up mode. This is enabled by holding the DOWN button during the start-up sequence. When enabled, the following will be displayed.
The following times are changed when in speed up mode.
Item / Normal / Speed UpCompressor anti-cycle delay / 5 min. / 10 sec.
Maximum defrost time / 10 min. / 20 sec.
Compressor stabilisation time / 5 min. / 5 sec.
LP bypass after defrost time / 8 min. / 2 sec.
LP bypass after normal compressor start / 3 min. / 2 sec.
Maximum defrost time / 10 min. / 20 sec.
Speed Up / 2 min. / 0
Note. If the NR-1 is left in Speed Up mode for longer than 30 minutes, the control will perform a self reset so it returns to normal.
Dirty filter
This feature provides a timer, which operates while the indoor fan is running. When the timer expires, the following occurs:
§ FiLt is displayed on the NR-1
§ The common fault terminal is activated
§ FILTER icon blinks on the NC-4 (This must be enabled by parameter 18 on the NC-4)
To reset the expired filter timer, the following can be done:
§ Manually reset the NR-1 by pressing UP+DOWN+SET
§ Press RESET (softkey#4) on the NC-4 when it appears.
The parameter below enables the filter timer.
Dirty Indoor Fan Filter
Type / ID / Default / Min. / Max. / Scaling / UnitsInstaller / 7 / 0 / 0 / 1 / 1 / ON / OFF
The parameter below is used to adjust the time which the indoor fan operates before the filter is considered dirty.
Dirty Indoor Fan Filter Time
Type / ID / Default / Min. / Max. / Scaling / UnitsInstaller / 8 / 30 / 0 / 255 / 1 / Days
The parameter below enables service personal to see how long the indoor fan has been running. This starts at zero and stops at the specified dirty filter time above.
Current Dirty Filter Time
Type / ID / Default / Min. / Max. / Scaling / UnitsService / 25 / 0 / 0 / 255 / 1 / Days
External System Disable
The system can externally be disabled by such things as timers and building management systems. To disable the system, 24VAC(R) must be connected to the AUX.A terminal.
Note. If a defrost cycle is being perform while the external disable is activated, it will continue until the cycle has completed.
External After-Hours Override
When used in conjunction with the NC-4, the NR-1 provides an input (AUX.B) for a momentary push button which forces the NC-4 to enter the ‘WAKE’ period for an adjustable length of time. This is ideal for an office situation where staff are working after-hours. The following parameter is used to adjust the duration of the after-hours override.
After-hours Run-On Time
Type / ID / Default / Min. / Max. / Scaling / UnitsInstaller / 4 / 60 / 1 / 255 / 1 / Minutes
Indoor Fan
While the user display is in the ‘Normal’ mode, the following will be displayed when the indoor fan is operating.
There are two modes of operation for the fan, Automatic and Manual.
Automatic
In automatic mode, the indoor fan will cycle ON/OFF with the compressor and always starts 10 seconds after the compressor.
For 24Vac thermostats, the fan is considered automatic if the FAN(G) input is active within 1 second of COMP(Y) input.
Continuous Fan
In this mode, the indoor fan will run continuously and the compressor will have no effect. This is enabled by applying 24Vac to the FAN(G) STAT terminal or pressing the FAN button on the NC-4.
For 24Vac thermostats, the fan is considered continuous if the FAN(G) input is active more than 1 second before the COMP(Y) input. Also, if the FAN(G) input is still active 5 seconds after the COMP(Y) input is cleared
Indoor Fan During Defrost
When the system enters defrost, the indoor fan will stop 15 seconds into the defrost cycle. Once the defrost is completed, the indoor fan will start in 15 seconds later.
In applications were the indoor fan must continue to operate during defrost, the following parameter must be enabled.
Indoor fan operate during defrost
Type / ID / Default / Min. / Max. / Scaling / UnitsInstaller / 5 / 0 / 0 / 1 / 1 / ON / OFF
Loss of FAN(G) input
If the FAN(G) input is not detected within 10 seconds of the COMP(Y) terminal, the system will be stopped. This will also occur if the FAN(G) input is removed while the COMP(Y) input is still active. This is intended to protect the system from operating without the indoor fan. If this situation occurs, the following is displayed on the screen.
Cooling Operation
In normal cooling, the reversing valve remains de-energised and the following sequence is executed.
§ A call for cooling is made by either the COMP (Y) terminal or the NC-4. Note. This must be present for at least two seconds before it is recognised.
§ Once the call for cooling has been recognised, an additional delay of three seconds is provided to give a total of 5 seconds from the call for cooling to the starting of the compressor.
§ Once the compressor has started, there is a further 5 seconds delay before the outdoor fans starts.
§ If the indoor fan is in automatic mode, the fan will start 10 seconds after the compressor starts. If in continuous mode, the indoor fan will operate irrespective of the above sequence. For more detail, see the section “Indoor Fan”
When the user display is in the ‘Normal’ mode, the following will be displayed during cooling.
When the call for cooling is removed the compressor and outdoor fan stop together. If the indoor fan is in Automatic mode, it will stop 5 seconds later.
Heating Operation
In normal heating the reversing valve must be energised. This is done by connecting 24VAC (R) to HEAT (B) terminal or automatically by the NC-4.
§ A call for heating is made by either the COMP (Y) terminal or the NC-4. This must be present for at least two seconds before it is recognised.
§ Once the call for heat has been recognised, an additional delay of three seconds is provided to give a total of 5 seconds from the call for heat to the starting of the compressor.
§ Once the compressor has started, there is a further delay of 5 seconds before the outdoor fan starts.