Peerless PFC-850 Purefire Commercial PB Heat Instruction Manual
- June 14, 2024
- Peerless
Table of Contents
Peerless® PureFire®
PFC-850/1000/1500 MODBUS Application Supplement
NOTICE
These instructions are intended as a supplement to the Peerless® PureFire® Installation, Operation and Maintenance Manual and are intended for use by a qualified technician.
A. Scope
PFC-850, PFC-1000 and PFC-1500 boilers are factory equipped with a 852IF interface adapter which allows external communication and control via the Modbus serial communication protocol. This document provides information about the data registers and values associated with the Modbus protocol.
- With the addition of a gateway device (stock code 54486), the control allows communication to BACnet™ MS/TP or BACnet™/IP protocols.
- Another gateway device (stock code 54487) is required to communicate with the LonWorks® protocol. Instructions for these devices are available separately.
B. Specification
Table 1: 852IF Analog Interface Specifications
| Communications Protocol | Modbus RTU |
|---|---|
| Default Dependent Address | 0x01 |
| Baud Rate | 9600 bps |
| Data Length | 8 |
| Parity | None |
| Stop Bits | 1 |
| Physical Layer | RS485 (2-wire) |
| Modbus 1A Connection | J7-1 |
| Modbus 1B Connection | J7-3 |
C. Wiring 852IF
Figure 1 shows the wiring of the 852IF interface board on the PFC-850,
PFC-1000 and PFC-1500 boiler.
The Modbus harness (PF7030) is used to connect from the J7 connector to Modbus
or an approved Modbus Gateway device.
Figure 1: Wiring Schematic
COLOR
ABBREVIATION KEY
BK BLACK
BL BLUE
BR BROWN
GN GREEN
GY GREY| OR ORANGE
PK PINK
PR PURPLE
RD RED
WH WHITE
YE YELLOW
LOW VOLTAGE SIZE 16/18 AWG TYPE TW, TEEN OR TEW/AWM WIRE
120 VAC VOLTAGE SIZE 16/18 AWG TYPE TW, TFFN OR TEW/AWM WIRE
PF-850/1000/1500 WIRING TERMINALS
- BRNR #1 POWER
- 120V CONTROL SUPPLY
- ALARM DRY CONTACTS
- CASCADE LINK DEPENDENT BOILER
- CASCADE LINK MASTER BOILER
- MODBUS INPUT
- 0-10V ANALOG INPUT
- SYSTEM SENSOR
D. Modbus Address
In order to communicate with several boilers, each boiler must be given a discrete Modbus Address.
- By default, this Modbus address is 1.
- To change the Modbus address use the menu selection in the Installer menu under “Burner Settings” for “Modbus Address” right after “Cascade Address”.
- The Modbus Address may be set to any value between 0 and 254.
E. Modbus Operation
1. Holding Registers: Table 2 below shows the Modbus holding registers for the 852IF. Further tables detail potential values for some of these registers.
Table 2 – 852IF Holding Registers
Holding Register
| **Access*| Parameter Name| Conversion| Range
---|---|---|---|---
Dec.| Hex.| Read**|
Write
100
| 0064| X|
X
| Modbus Units| | 0 = °C; 1 = °F
101
| 0065|
X
| | Device Type| | 3 = Standalone PFC-850/1000/1500
102
| 0066|
X
| | State (Managing)| | See Table 3
103
| 0067|
X
| | Status (Managing)| | See Table 4
104
| 0068|
X
| | Error Code (Managing)| | See Table 5 & 6
105
| 0069|
X
| | Warning Code| | See Table 7
106
| 006A| X|
X
| CH Setpoint| Value/100= Temp| Temp is in C or F depending on Modbus Units
107
| 006B| X|
X
| DHW Setpoint| Value/100= Temp| Temp is in C or F depending on Modbus Units
108
| 006C| X|
X
| Not Applicable| | Not Applicable
109
| 006D| X|
X
| Not Applicable| | Not Applicable
110
| 006E| X|
X
| CH Mode| | Table 8
111
| 006F| X|
X
| DHW Mode| | Table 9
112
| 0070|
X
| | Supply Temperature| Value/100= Temp| Temp is in C or F depending on Modbus Units
113
| 0071|
X
| | Return Temperature| Value/100= Temp| Temp is in C or F depending on Modbus Units
114
| 0072|
X
| | DHW Temperature| Value/100= Temp| Temp is in C or F depending on Modbus Units
115
| 0073|
X
| | Flue Gas Temperature| Value/100= Temp| Temp is in C or F depending on Modbus Units
116
| 0074|
X
| | Header Temperature| Value/100= Temp| Temp is in C or F depending on Modbus Units
117
| 0075|
X
| | Firing Rate (Managing)| Auto| 0 to 100%
118
| 0076|
X
| | Not Applicable| |
119
| 0077|
X
| | Flame Current| | µA
120
| 0078|
X
| | Water Pressure| | Not Applicable
121
| 0079|
X
| | Analog In| | 0-10 VDC
122
| 007A|
X
| | Not Applicable| | Not Implemented
123
| 007B|
X
| | Not Applicable| | Not Implemented
124
| 007C|
X
| | CH Pump| | 0-100%
125
| 007D|
X
| | DHW Pump| | 0-100%
126
| 007E|
X
| | Successful Ignitions| | Value shown x 16 = Ignition Count OK
127
| 007F|
X
| | Failed Ignitions| | Value Shown = Ignition Count Failed
128
| 0080|
X
| | Flame Failures| | Value Shown = Flame Count Failed
129
| 0081|
X
| | Burner On (CH)| | Burner High Hours = Burner On Time (Hours)
130
| 0082|
X
| | Burner On (DHW)| | Burner Med Hours = Burner DHW Hours
131
| 0083|
X
| | Not Applicable| | Not Implemented
150
| 0096|
X
| | State (Dependent)| | See Table 3
151
| 0097|
X
| | Status (Dependent)| | See Table 4
152
| 0098|
X
| | Error Code (Dependent)| | See Table 5 & 6
153
| 0099|
X
| | Firing Rate (Dependent)| | 0-100%
2. Temperature Input/Output: Be sure to change the Modbus units to the appropriate value (Fahrenheit or Celsius) before reading or writing these values. When reading the values of register number 106, 107, 112, 113, 114, 115 & 116 the value must be scaled by dividing by 100. When writing the value for register numbers 106 & 107, the desired value must be multiplied by 100 before entering. This scaling is the same for both Fahrenheit and Celsius units.
- In order to write CH set point, boiler must be set to CH Mode 0 or 3.
3. Successful Ignitions: The value read from register 126 (Successful Ignitions) must be multiplied by 16 to get the actual value.
4. State & Status: The registers shown in Tables 3 & 4 give information about the current condition of the control. Note that there are “State” & “Status” values that can be read for both the Managing control and the Dependent control.
Table 3: Control State Descriptions
STATE
| State Name| Description
Dec|
Hex
0
|
0x00
| RESET_0| Initialization
1
|
0x01
| RESET_1| Initialization
2
|
0x02
| STANDBY_0| Standby waiting for heat demand
3
|
0x03
| SAFETY_ON| Ignition Sequence
4
|
0x04
| SAFETY_OFF| Ignition Sequence
5
|
0x05
| PRE_PURGE| Ignition Sequence
6
|
0x06
| PRE_PURGE_1| Ignition Sequence
7
|
0x07
| IGNIT_0| Ignition Sequence
8
|
0x08
| IGNIT_1| Ignition Sequence
9
|
0x09
| BURN_0| Following Boiler Demand
10
|
0x0A
| POST_PURGE_0| Purging Combustion Chamber
11
|
0x0B
| POST_PURGE_1| Purging Combustion Chamber
12
|
0x0C
| PUMP_CH_0| Following CH Demand w/o Heat Input
13
|
0x0D
| PUMP_CH_1| Post purge Pumping after CH Demand
14
|
0x0E
| PUMP_HW_0| Following DHW Demand w/o Heat Input
15
|
0x0F
| PUMP_HW_1| Post Purge Pumping after DHW Demand
16
|
0x10
| ALARM_1| Error Handling
17
|
0x11
| ERROR_CHECK| Error Handling
18
|
0x12
| BURNER_BOOT| Controller (re)start
19
|
0x13
| CLEAR_E2PROM_ERROR| Error Handling
20
|
0x14
| STORE_BLOCK_ERROR| Error Handling
21
|
0x15
| WAIT_A_SECOND| Error Handling
Table 4: Control State Descriptions
STATE
| State Name| Description
Dec|
Hex
0
|
0x00
| STANDBY| Standby waiting for Heat Demand
14
|
0x0E
| BLOCK| Error Handling
10
|
0x0A
| ALARM| Error Handling
15
|
0x0F
| FROST_PROTECT| Freeze Protection Demand
16
|
0x10
| CH| Central Heating Demand
17
|
0x11
| RESET_STATE| Initializing
18
|
0x12
| STORAGE| DHW Demand
19
|
0x13
| Not Applicable| Not Applicable
20
|
0x14
| Not Applicable| Not Applicable
21
|
0x15
| STORE_WARM_HOLD| DHW Demand (Store Warm Hold)
5. Error Codes: There are two types of error codes: Blocking and Lockout. Blocking errors will prevent the control from firing the burner until the condition causing the error is corrected. Lockout errors require a manual reset at the control to resume normal boiler operation. Table 5 (below) lists Lockout error codes and their descriptions. Table 6 lists Blocking error codes and their descriptions.
Table 5: ERROR_NUMBER (Lockout Errors)
Error Number
| Error Description| Display Code
Dec|
Hex
1
|
0x01
| Fan Speed Error – Incorrect fan speed for more than 60 seconds|
A33
2
|
0x02
| Ignition Error – 3 consecutive failed ignition attempts|
A01
5
|
0x05
| Internal Control Error – Gas Valve Relay Error|
A04
6
|
0x06
| Internal Control Error – Safety Relay Error|
A06
9
|
0x09
| Internal Control Error – RAM Error|
A09
10
|
0x0A
| Internal Control Error – E2PROM Out of Date|
A12
11
|
0x0B
| Boiler Return Temperature Higher than Supply|
A50
12
|
0x0C
| Internal Control Error – Communication Error E2PROM|
A10
13
|
0x0D
| Internal Control Error – State Error|
A13
14
|
0x0E
| Internal Control Error – ROM Error|
A14
15
|
0x0F
| Internal Control Error – Air Switch Not Open|
A21
16
|
0x10
| Internal Control Error – 15MS XRL Error|
A15
17
|
0x11
| Internal Control Error – Air Switch Not Closed|
A22
18
|
0x12
| High Temperature Limit Open|
A03
19
|
0x13
| Internal Control Error – Stack Error|
A18
20
|
0x14
| Flame Detected After Shutdown|
A19
21
|
0x15
| Flame Detected Before Ignition|
A20
22
|
0x16
| Internal Control Error – 20MS XRL Error|
A16
23
|
0x17
| Internal Control Error – 41MS Error|
A32
24
|
0x18
| Flame Failure – 3 failures during one heat call|
A02
25
|
0x19
| Flow Switch Open / Circulator Off|
A23
26
|
0x1A
| Flow Switch Closed / Circulator On|
A24
27
|
0x1B
| Internal Control Error – Flag Byte Integrity Error|
A09
28
|
0x1C
| Internal Control Error – AD HI CPL Error|
A09
29
|
0x1D
| Internal Control Error – AD LO CPL Error|
A09
30
|
0x1E
| Internal Control Error – Register Error|
A09
Table 6: ERROR_NUMBER (Blocking Errors)
Error Number
| Error Description| Display Code
Dec|
Hex
31
|
0x1F
| Internal Control Error – REFHI Too Low Error|
E45
32|
0x20
| Internal Control Error – REFHI Too High Error|
E46
33|
0x21
| Internal Control Error – REFLO Too Low Error|
E47
34|
0x22
| Internal Control Error – REFLO Too High Error|
E48
35|
0x23
| Unexpected Flame Detected|
E20
36|
0x24
| Interlocks Open – Gas Press, LWCO or External|
E31
39|
0x27
| High Exhaust Vent Temperature (>194°F; >90°C)|
E30
40|
0x28
| High Return Temperature|
E32
41|
0x29
| Blocked Condensate Drain|
E26
43|
0x2B
| Poor Ground Connection|
E24
44|
0x2C
| Hot & Neutral Legs Reversed|
E21
45|
0x2D
| Frequency Error|
E23
46|
0x2E
| Poor Ground Connection|
E24
47|
0x2F
| Internal Control Error – WD Comm Error|
E42
51|
0X33
| Supply Sensor Not Connected|
E01
52|
0X34
| Return Sensor Not Connected|
E02
55|
0X37
| DHW Sensor Not Connected|
E04
57|
0X39
| Flue Sensor Not Connected|
E05
59|
0X3B
| Supply Sensor Shorted|
E11
60|
0X3C
| Return Sensor Shorted|
E12
63|
0X3F
| DHW Sensor Shorted|
E14
65|
0X41
| Flue Sensor Shorted|
E13
66|
0X42
| Reset Button Error (Activated 7 times in 1 minute)|
E51
67|
0X43
| Flap Not Closed|
E52
68|
0X44
| Flap Not Open|
E53
6. Warning Errors: Table 7 shows values for warning codes. Warnings are associated with temperature sensors that are either shorted or open. At the boiler these errors are indicated by a flashing burner control displays (in the electrical enclosure on the boiler).
Table 7: WARNING_NUMBER
Warning Number
| Error Description| Display Code
Dec|
Hex
1
|
0x01
| Outdoor Sensor Shorted|
W01
2|
0x02
| DHW Sensor Not Connected|
W02
3|
0x03
| DHW Sensor Shorted|
W03
4|
0x04
| Flue Sensor Not Connected|
W04
255|
0xFF
| All Sensors Operating Correctly|
7. CH & DHW Mode: Table 8 shows register values for central heating (CH) modes. These values are typically set upon commissioning based on the piping configuration. Table 9 shows the values for domestic hot water (DHW) modes. Again, these values are dependent on the piping and wiring configuration.
Table 8: CH Mode
CH Mode Number
| CH Mode Description| Description
Dec|
Hex
0
|
0x00
| Indoor Thermostat| Boiler maintains a fixed, user-defined, temperature
setpoint
Boiler responds to thermostat demand targeting temperature setpoint
1
|
0x01
| Thermostat and Outdoor Reset| Boiler temperature is calculated based on
outdoor temperature
Boiler responds to thermostat demand targeting the calculated temperature
2
|
0x02
| Full Outdoor Reset| Boiler temperature is calculated based on outdoor
temperature
Boiler maintains targeted temperature calculated by the control with no
thermostat input
Closure of terminals #1 & #2 causes a temperature setback of 18°F
3
|
0x03
| Permanent Demand| Boiler maintains a fixed, user-defined, temperature
setpoint
Boiler maintains the fixed temperature setpoint with no thermostat input
Closure of terminals #1 & #2 causes a temperature setback of 18°F
4
|
0x04
| 0-10 V Input to modulate setpoint| Boiler starts if analog voltage is above
1.5 VDC
Boiler temperature corresponds to an external analog input between 2 VDC (68°
F) and 10 VDC (195° F)
5
|
0x05
| Not Applicable|
6
|
0x06
| Hydro-Air Unit| Boiler maintains a fixed, user-defined, temperature setpoint
Boiler responds to thermostat demand targeting temperature setpoint
Table 9: DHW Mode
DHW Mode Number
| DHW Mode Description| Description
Dec|
Hex
0
|
0x00
| No DHW| No indirect hot water tank is connected
Boiler will not respond to any input on terminals #5 & #6
1
|
0x01
| DHW store with sensor| Indirect hot water tank is piped in the system and a
tank sensor is used
Boiler monitors indirect tank temperature using sensor input on terminals #5 &
6
2
|
0x02
| DHW store with thermostat| Indirect hot water tank is piped in the system
and a thermostat is used to monitor the tank temperature
Boiler responds to DHW call for heat when the circuit is made between
terminals #5 & #6
PB HEAT, LLC
131 S. CHURCH STREET • BALLY, PA 19503
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PF8215 R1 (05/23)
Printed in U.S.A