Resetting The Heater Control; Tco Resettable Lockout; Lockouts; Soft Lockout - Lochinvar POWER VENTED GAS HEATERS Installation And Operating Manual

PROBLEM
BLOWER RUNS
CONTINUOUSLY
HOT SURFACE IGNITER
NOT GLOWING
FOLLOWING WARM-UP
PERIOD
VENT PIPE TOO HOT

RESETTING THE HEATER CONTROL

•
Soft lockouts as diagnosed by the system error codes
require the gas control to be reset.
•
To reset the control, slide the "ON/OFF" switch to the
"OFF" position. Wait for 10 seconds and move the
switch back to the "ON" position.
•
If the problem that caused the control to lock out has
not been corrected, the control will remain or again go
back into lockout.

TCO RESETTABLE LOCKOUT

Reseting a High Limit (Thermal Cutout) trip requires
manual intervention and cannot be reset by just cycling
power to the control.
To reset the control, fi rst slide the "ON/OFF" switch to the
"OFF" position. Wait for 10 seconds and move the switch
back to the "ON" position.
A manual reset also requires turning the temperature
setting dial to the lowest (coldest) position for a minimum
of 10 seconds and then returning it to the desired setpoint.
A manual reset is allowed after each of the fi rst two TCO
trips. After a third TCO trip, the control enters a hard lockout
state and must be replaced.
Note: A high limit cutout indicates an overheating situation
or very high water temperatures. Contact your local service
provider to determine the cause of the overheating or
another reason for the malfunction.
54
POSSIBLE CAUSE(S)
1. Air pressure switch not closing due to
insuffi cient draft – check for:
a. Vent piping blocked
b. Piping length too long
c. Clogged/dirty blower
2. Disconnected, torn or blocked pressure
switch hose from air pressure switch to
blower housing
3. Defective pressure switch
4. High limit switch open due to excessive
vent temperature or defective switch
1. 120VAC polarity reversed at 120VAC
outlet receptacle
2. Defective hot surface igniter
3. Defective gas control valve/thermostat
1. Blower high limit switch fails to open -
switch defective
2. Not enough dilution air to mix with fl ue
gases
3. Air in room too hot for mixing with fl ue
gases
4. Wrong burner orifi ce
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CORRECTIVE ACTION
1. Determine cause of insuffi cient
draft. Check draft with manometer at
pressure switch
a. Remove blockage
b. Reduce vent length/increase vent
size
c. Clean blower wheel
2. Reconnect or replace pressure switch
hose
3. Replace defective pressure switch
4. Determine cause of overheating check
for: overfi ring, insuffi cient air supply,
high ambient air temperature
1. Reverse polarity at 120VAC outlet
receptacle
2. Replace igniter
3. Replace gas control valve/thermostat
1. Replace blower high limit switch Replace
blower high limit switch
2. Proper air circulation must be provided for
combustion and dilution of fl ue temp
3. Increase ventilation to lower room
temperature
4. Install correct orifi ce.

LOCKOUTS

Soft Lockout

•
occurs when a system safety device trips to break the
sequence of operation. The control will retry the system
in a timed basis but will not reinstate operation until the
failure is corrected.

Hard Lockout

•
occurs when the main contrioller fails and must be
replaced.