LP-743 Rev. 000 Rel. 000 Date 8.25.20
19
Part 5 - Troubleshooting
115
System Sensor Open Short
Circuit
1. Connect System Sensor to Master boiler SYS terminal - see Wiring a Cascade System.
2. Check cable between System Sensor and Master boiler.
3. Ensure that the System Sensor is a 10k Ohm NTC.
4. Replace System Sensor. If problem persists replace the main control.
Warning
(Auto
Reset)
150
System Sensor Overheat
Press the Reset button to clear the Error Code.
If Error happens again:
1. Check for the correct functioning and positioning of the supply and return temperature probes of
each boiler.
2. Ensure that the System Sensor is a 10k Ohm NTC.
3. Check for the correct functioning and positioning of the System Sensor - check sensor resistance vs
Sensor Temperature Resistance table in boiler Installation Manual. Replace System Sensor.
Warning
(Auto
Reset)
441
Follower Boiler Missing from
BUS Connection
Press Reset to clear the Error Code.
If Error happens again:
Check the BUS wiring. Ensure it is intact and connected. Repair if necessary.
Warning
(Manual
Reset)
CONFL
Configuration Conflict
Each boiler connected to the BUS must have a unique address (parameter 0.4.6). No boiler can be
configured as «b-SIN».
1. Press OK. Choose and correct the boiler address. Press OK again.
2. If above process does not work, access parameter 0.4.6 and set the correct boiler address - see
Cascade Control Set-Up.
Blocking
(Auto
Reset)
NOAVL
Boiler Address Unconfigured
Boiler address is undefined (0.4.6 = UNDEF).
1. Press OK. Choose and correct the boiler address. Press OK again.
2. If above process does not work, access parameter 0.4.6 and set the correct boiler address - see
Cascade Control Set-Up.
Blocking
(Auto
Reset)
EMERG
Emergency Mode
1. The Follower has been disconnected from the BUS or no longer sees the Master on the BUS - check
the BUS connections. See Wiring a Cascade System.
2. The control has sensed a short circuit on the BUS connection. Disconnect the field wiring from the
BUS connection and confirm wiring.
3. Verify that the BUS polarity («B» and «T» connections) is consistent on all devices connected to the
BUS.
4. If problem persists replace the main control.
NOTE:
When in Emergency Mode the boiler operates in CH mode with a target boiler temperature =
Emergency Setpoint (2.10.3 for Master boiler, 34-40.10.3 for Follower boilers).
Warning
Display
Description
Possible Remedies
Error
Type
Table 5 - Boiler Error Codes
Important
Contact a qualified service technician for assistance if a Lockout Error occurs frequently. For safety reasons, the boiler will permit a maximum
of five (5) resets in 15 minutes (five [5] presses of the RESET button). A sixth (6th) attempt within this 15 minute period will lock out the boiler
permanently. The boiler will only operate again after the electrical supply has been disconnected and reconnected.
Repeated Lockout Error conditions could indicate a serious error with the boiler or installation. Failure to contact a qualified service technician
to troubleshoot the error could result in substantial property damage, serious personal injury, or death.
*Error is resettable remotely via HTP Tele-Diagnostic Service, HTP Remote Contractor.
The Cascade Master can display all faults generated by the cascade system, whether the boiler is the Master or a Follower.
