Trinity Lx
│
Installation and Operation Instructions
Lx – WH Series
84
PROBLEM
POSSIBLE CAUSE
CORRECTIVE ACTION
Lockout or Hold 67 – ILK
OFF
Insufficient water pressure (Lx150-
400 only)
Ensure at least 15PSI at water heater outlet. Refer
to Supplementary Documentation section 2.0
System Piping.
External Limit Tripped
Indication that an external limit (wired to “LIM”)
is open. Not a problem with water heater, check
external limit.
Insufficient flow for Flow Switch
(Lx500-800 only)
Check plumbing, ensure circulator is operating.
Tripped Thermal Fuse (Lx500-800
only)
Check Thermal Fuse on the back of the heat
exchanger (accessed from the rear of the cabinet).
If tripped contact NTI.
Tripped High Vent Pressure Switch
(Lx500-800 only)
The high vent pressure switch will trip when the
combustion chamber is blocked or venting is too
restrictive. Check venting and clean combustion
chamber.
Lockout or Hold 79 – Outlet
High Limit
CH or DHW settings
Check if CH and/or DHW setpoint temperature
plus off hysteresis exceed “High limit” setpoint –
factory setting = 210°F (99°C).
CH or DHW pump problem
See
"
Inoperative CH or DHW pump
"
below.
Incorrect “Outlet high limit” setting
Increase “Outlet high limit” setting; maximum
setting = 210°F (99°C).
Lockout or Hold 81 – Delta T
limit
OR
Water heater making banging
or hissing sounds
Insufficient water flow
Check Fuse
"
A
"
Check water heater pump.
Ensure plumbing is correct.
Refer to
Supplementary Documentation section 2.0
System Piping. Check that water pressure is at
least 15PSI.
Water heaters Only
- Water heater heat
transfer surfaces may be fouled with scale or
magnetite. Clean with Fernox DS-40 Descaler
and Cleanser. See Table 10-1.
Lockout 82 – Stack limit
Dirty heat exchanger
Inspect and if required clean the combustion
chamber and/or heat exchanger. Refer to 14.0
Annual
Maintenance
and
Inspection
and
Supplementary Documentation section 2.0 System
Piping.
Incorrect “Stack limit setpoint”
Unless installed in Canada with PVC exhaust
venting, set “Stack limit setpoint” to maximum
setting of 220ºF (104ºC). In Canada PVC exhaust
venting is limited to 149ºF (65ºC).
Faulty sensor
Check resistance of stack sensor and compare to
thermistor resistance chart, see Table 17-2.
Lockout or Hold 85 –
Inlet/Outlet Inversion Limit
Pump flowing in the wrong
direction
Ensure water circulation is flowing into the water
heater at the fitting closest to the wall.
Incorrect factory sensor wiring
Disconnect flue sensor cable; screen should
display “Hold 95 – Stack sensor fault”; if not
contact NTI.
Lockout or Hold 88 – Outlet
T Rise limit
Insufficient water flow
See Lockout or Hold 81.
Hold 91– Inlet sensor fault
Sensor disconnected
Verify that 2-position Molex connector on
wiring harness is securely attached to mating
connector on inlet sensor.
Inspect sensor wiring.
