ICC Mirius, Installation Instructions Manual

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Modbus / Electric Water Heaters
Central Control Board Major State Definitions
Table 44. ModBus / Electric Water Heaters Central Control Board (CCB) State
Value State
0 Off (Standby)
6 Heating
8 Fault
Energy Management System (EMS) Control
Commercial Electric water heaters with Xi controls use a single bit setting method. Within the EMS Mode-Status point, one bit
command (bit 15) sets it in EMS mode, and other ends EMS mode. Once in EMS mode, another bit command (bit 0) enables heating;
another disables heating.
Once in EMS mode the EMS Mode Refresh command must be periodically issued which clears a third bit (bit 14) to maintain EMS
mode, otherwise the heater will end EMS mode and resume normal operation.
Table 45. ModBus /Electric Water Heaters Energy Management System (EMS) Control
Decimal Hex Value Response
3840 0x0F00 No EMS control 0 / 0x000
3841 0x0F01 Put into EMS Mode^ 49152 / 0xC000
0000 0x0000 EMS Disable heating^ 49152 / 0xC000
0001 0x0001 EMS Enable heating^ 49153 / 0xC001
3584 0x0E00 EMS Mode Refresh^ (must write within 30 seconds or
EMS mode ends.) 15 seconds or less recommended
49152 / 0xC000 or 49153 / 0xC001 depending
on whether or not heating is enabled.
NOTE:
The start of a heating cycle also depends on other factors, like
Tank Temperature dropping below Setpoint – Differential and External
T’stat Call for Heat if that option is enabled.
^Depending on when you poll the register, you may read bit 14 as 1, which is why a “C” (in hexadecimal form) might briefly reply with
“8”. This is due to the control setting this bit and if it not cleared periodically by the Modbus command, heating is disabled.
After disabling EMS mode with write of 3840, read-back might have bits 14 and 1 possibly still set. To make sure these bits are clear,
write a 0000 to clear bit 1 and 3584 to clear bit 14.
Fault Codes and Warnings
Note:
Any Fault not listed is an internal CCB failure fault.
Table 46. BACnet/Electric Water Heaters Fault Codes and Warnings
Index Range
(Decimal)
Index Range
(Hex Code) Value
0 0 0x000 0x000 Okay (No Fault)
1 6 0x001 0x006 Memory
24 0x018 Incorrect Model
51 56 0x033 0x038 Power Monitor
69 72 0x045 0x048 Temperature Probe Open or Short
153 154 0x099 0x09A Communications Fault
165 0x0A5 High temperature ECO (Energy Cut Off)
175 0X0AF Safety Relay Closed fault
176 188 0x0B0 0x0BC CCB internal errors
193 194 0x0C1 0x0C2 Processor Clock
198 201 0x0C6 0x0C9 Non-volatile Memory
205 217 0x0CD 0x0D9 Powered Anode
431 0x1AF Safety Relay Opened fault
1037 1037 0x40D Element Open Warning