HTP EL-399NVWH - Manual (Page 65)

65
LP- 346 REV. 3.20.14
Fault Code FLU
HIGH FLUE PRESS FLU
PUMP ON
This display indicates that there is excessive
flue pressure. This code resets automatically
after the high pressure condition is resolved.
The second line indicates the status of the
pump. 1. Assure that the flue is not blocked.
2. Check the switch wiring by applying a jumper in place of the
switch. If the code clears with the jumper in place, REPLACE the
flue switch and connect the wires to the new switch BEFORE
running heater.
WARNING: Do not use jumper to remedy an FLU error. Faulty switch MUST be replaced. Failure to do so could result in serious injury or death.
Fault Code LOU
24 VOLT LOW LOU
PUMP ON
This display indicates that the 24 volt power
supply on the control is damaged or over-
loaded. This code resets automatically if it is
the result of an overload and that overload con-
dition is removed. The second line indicates the
status of the pump. Note that while 24 volt
power is low, the pump output will be on.
1. Check line voltage. It must be between 100 and 128 volts.
2. If available, connect PC, and using HTP service software check
the 24v supply display in the lower left corner of the screen. The
number displayed here must be greater than 128 and should be no
greater than 250. Use this as a troubleshooting guide as you follow
the steps below.
3. Remove the 10 pin Molex connector from customer connection
board. If the message clears, then the problem is with the external
sensor wiring. Examine the external sensor wiring for shorts to the
ground, repairing as necessary. If the message is still present and
the heater is so equipped, disconnect the UL 353 low water cut-off
to see if the message clears. Replace the faulty part. Check the low
voltage wire harness in heater for shorts to ground.
4. If a message only occurs when the burner tries to light, check the
gas valve for excessive current draw.
5. If a message is present with the low voltage harness
disconnected from the 926 control board, replace the 926 control
board.
Fault Code F00
WATER HIGH TEMP F00
PUMP ON
This display indicates if the water in the heater
has overheated. This code indicates a serious
safety issue and the heater will not restart until
it cools sufficiently and a technician repairs the
cause of overheating and pushes the RESET
button on the display. This is a serious situation
and is indicated by the red light on the display
illuminating and the word LOCKOUT flashing
on the display. During this lockout fault, the
pump will be on as indicated on the second line
in an effort to cool the heater down. 1. Check circulator pump operation
2. If the circulator pump is running, be sure that there is water in the
system and that the water is moving through the system as
intended. Be sure that all correct ball valves and or zone valves are
open or closed as intended.
3. Observe the temperature/pressure gauge. If the water is not too
hot and this message is displayed, check the wiring to the water
ECO sensor and repair if necessary. If the wiring is ok and this code
is still present and the water is not excessively hot, replace the ECO
sensor.
Fault Code F01
FLUE TEMP/WAT LV F01
PUMP ON
This code indicates that one of the safety
interlock switches present in the unit has
tripped. There are several interlock switches
that could possibly trip and cause this error.
The following switches are installed standard
equipment in all boilers.
1. Flue ECO – Trips if the flue temperature is
excessive. This switch has to be manually
reset.
2. Blocked vent pressure switch (BVPS) –
This switch trips if there is excessive
pressure in the flue and automatically
resets.
3. (EL-299 / 301 / 399 VWH models ONLY)
Boiler module front temperature switch -
Trips if there is excessive heat on the front
of the heat exchanger.
The UL 353 Low Water Cutoff (LWCO) is
optional and may be installed on the boiler.
This device trips if the water level in the boiler
is low. This switch must be manually reset.
1. Check to see if the boiler with the F01 code displayed has an
optional UL 353 LWCO installed.
2. If so, check to see if the indicator light on shows that the LWCO
has tripped.
3. If the LWCO has tripped, restore the proper water level. Then
manually reset the switch and boiler.
4. If there are no optional switches or none of the indicator lights
is illuminated on the optional switches then use an ohmmeter to
test each of the standard switches one at a time. Turn the
power off to the boiler and disconnect the switch to be tested
from the boiler to determine which one has tripped.
When you find the tripped switch investigate the cause of the
fault based on the purpose of the switch. NOTE: The common
reasons for the temperature switches to trip are a) low water
flow through the boiler, or b) poor heat transfer from the water
to the load.
5. If no switches are tripped, push RESET on the boiler. If the
boiler tries to ignite or ignites and only runs for a short time and
the F01 code returns, investigate the flue for blockage.
Fault Code F02
SUPPLY SENSOR F02
PUMP ON
This display indicates that the supply tempera-
ture sensor of the heater has failed. This code
indicates a serious safety issue and the heater
will not restart until the sensor is replaced by a
technician and he pushes the RESET button on
the display. This situation is indicated by the
red light on the display and the flashing word
LOCKOUT. During this lockout fault, the pump
will be on as indicated on the second line of the
display. 1. Check the electrical connection to the thermistor on the outlet
manifold. Verify 5 VDC by checking in Molex connector. If there is
no 5 VDC, check the harness. If harness is OK, replace control.
NOTE: The heater will reset automatically. Verify thermistor values
by referencing chart in this manual.
2. Replace thermistor if necessary.