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110328-02 - 6/22
ALTA
Installation, Operating & Service Instructions
18
Troubleshooting
(continued)
Table 18-5: Active Fault Code and Corrective Actions (continued)
Detailed Fault Code found on "
b
" and "
c
" menus in brackets, e.g. [
1
.
0
].
Code
Name
Possible Cause
Corrective Action
H25
E25
Hardware Fault Control damaged.
Check control, cycle power, replace if necessary.
H26
E26
Calibration
Fault
Too long running without
running at minimum capacity.
Adaptation has not been
possible.
Cycle power to initiate calibration. After
H24
boiler runs at forced
raised minimum modulation.
Too long running without
running at calibration
capacity (approx. 50%).
Calibration has not been
possible.
Refer to Supply High Limit (Code
H04
/
E04
) for corrective actions.
Cycle power to initiate a calibration.
H27
120 VAC
Supply Fault
120 VAC supply voltage less
than 73 VAC.
Check 120 VAC supply, correct issues as required.
H28
24 VAC Supply
Fault
Control 24 VAC wrong
frequency or high electrical
noise.
Check control, replace if necessary.
E29
Excessive
Reset
Selection
Control
!
reset
button has
been selected too often.
To clear, cycle power to control and press
!
reset
button above
local display.
H30
Sequencer
Fault
[
30
.
0
] Duplicate Slave Boiler
Addresses.
Ensure each peer-to-peer boiler has a unique slave address between
1 and 8.
[
30
.
1
] Sequencer slave has
lost communication with
Sequencer Master, master
header sensor failure.
Check boiler to boiler connection wiring.
Check master is powered and configured.
Check header sensor wiring or configuration.
[
30
.
2
] Multiple sequencer
masters detected.
Check each boiler Lead Lag Master Enable, parameter
L01
, setup.
Only one boiler may be set as Sequencer Master Enabled.
[
30
.
3
] Modbus setpoint
signal.
(Feature not available with local user display.) Check wiring to Energy
Management System.
[
30
.
4
] Modbus modulation
signal.
H31
Variable Speed
Pump Fault
Variable Speed Pump
feedback fault.
Check wiring to Variable Speed Pump. Defective pump electronics or
control, replace pump or control if necessary.
H32
Zone Panel
Fault
[
32
.
0
to
32
.
3
] Zone Panel
Communication Lost.
Check wiring between panels and boiler. Check Zone Panel Dip
Switch Settings:
- Set Master/Slave Dip Switch on zone panel to "master" all
others set to "slave".
- Set ZC Dip Switch Zone Panel 1 "ZC1" to "ON".
Zone Panel 2 "ZC2" to "ON", etc.
Cycle Power.
[
32
.
4
] Zone Panel Electronics
Failure.
Check following:
- Wiring Zone Panel main and daughter board.
- Power up one panel at a time to isolate problem.
- Replace panel if problem persists.
[
32
.
5
] Duplicate Zone Panel.
Check the following:
- Each ZC Dip Switch set to a unique setting: ZC1, ZC2, ZC3, ZC4
- When multiple switches are set to "ON" the zone is reported as
panel 1.
