NTI FTG 600 - Page 60

Installation & Operation Manual │ FTG
60
Table 16-2 Troubleshooting Chart
PROBLEM
POSSIBLE CAUSE
CORRECTIVE ACTION
Bloc’d Filter Switch
Blocked Air Filter Switch has opened – clean or
replace the air filter and clear the lockout.
WARNING: DO NOT OPERATE THE
BOILER WITHOUT THE AIR FILTER,
CONTAMINANTS WILL ENTER THE
BURNER RESULTING IN INPROPER
OPERATION LEADING TO PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
Lo Gas Pres. Switch
Low Gas Pressure Switch has opened – the
incoming gas line pressure has dropped below 3.5
in. w.c., causing the low gas pressure switch
(mounted to the side of the gas valve) to open.
Correct gas line pressure problem then clear the
lockout.
Hi Gas Pres. Switch
High Gas Pressure Switch has opened – the gas
valve manifold pressure exceed 3 in. w.c., causing
the high gas pressure switch (installed down-stream
of the gas valve) to open. CONTACT NTI FOR
ASSISTANCE
Ext. Limit Switch
An External Limit Device (field installed and wired
to the “Ext. Limit” contact of the boiler) has
opened. Not a problem with boiler, check the
external limit device.
Aux. Proof Switch
Auxilary Proof Switch (field installed and wired to
the “Aux. Proof” contact of the boiler) has opened.
Not a problem with the boiler, check the auxiliary
proof switch.
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
Appliance making banging or
hissing sounds
Insufficient water flow
 Check appliance pump.
 Ensure plumbing is correct. Refer to Section
10.0 System Piping. Check that water pressure is
at least 15PSI.
 Boiler 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 Section
15.0 Annual Maintenance and Inspection and
Section 10.0 Boiler and Heating 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 sensor and compare to
thermistor resistance chart, see Table 16-2.
Lockout or Hold 85 –
Inlet/Outlet Inversion Limit
Pump flowing in the wrong direction
Ensure water circulation through the boiler is in the
correct direction, see Figure 10-1.
Incorrect factory sensor wiring
Disconnect flue sensor cable; screen should display
“Hold 95 – Stack sensor fault”; if not contact NTI.