HTP EL-399 - Manual (Page 67)

67
LP- 293 REV. 5.20.14
This appliance has wire function labels on all internal wiring. Observe the position of each wire before removing it. Wiring errors may
cause improper and dangerous operation. Verify proper operation after servicing.
If overheating occurs, or the gas supply fails to shut off, do not turn off electrical power to the circulating pump. This may aggravate the
problem and increase the likelihood of boiler damage. Instead, shut off the gas supply to the boiler at the gas service valve.
D. USER INTERFACE DISPLAY
Cascade Control FAULT Codes
SCREEN DESCRIPTION POSSIBLE REMEDY
Fault Code EO3
System Sensor Failure
SYS SUPPLY SENSOR
PUMP OFF E03
This screen shows that there is a problem with the
system sensor circuit. The circuit could be open or
shorted. Possible reasons for this error are:
There is no system sensor connected to the
Master Boiler.
The system sensor is faulty.
There is a short circuit in the system sensor
wiring; possibly from a staple placed through the
wire, or damage to the wire causing both
conductors to touch.
The system sensor wiring is open due to defect or
damage.
Disconnect the system sensor from the wiring and
measure the resistance of it. Compare the
measured resistance to the table in this manual to
see if it corresponds to the temperature of the
sensor. If the resistance does not agree with the
sensor, replace the sensor. If the sensor is OK,
disconnect the sensor wiring from both the boiler
and the sensor and check continuity using an
ohmmeter. Repair or replace as necessary.
If this error is present, all boilers in the cascaded
group will run and ignite simultaneously when there
is a heat demand. Each boiler will modulate to
maintain set point temperature on its own supply
sensor. This code will reset automatically when
repair is complete. This code will not display if
system setting function ERROR SYSTEM SENS is
set to OFF.
Fault Code TT
Temperature Blocking TT Demand
TEMPER BLOCKING
PUMP ON TT
This screen indicates a temporary hold on the burner. There is a demand on the boiler, the pump is
powered on, but the temperature of the water at the supply sensor is too high for the boiler to ignite. This
occurs because the water temperature measured by the supply sensor is higher than the boiler
temperature
– ignition diff setting. This error will clear itself when the water temperature measured by the
supply sensor is less than the boiler temperature – ignition diff setting.
Fault Code DHW
Temperature Blocking DHW Demand
TEMPER BLOCKING
PUMP ON DHW
This display indicates a temporary hold on the burner. There is a demand on the boiler from the DHW
circuit for heat, the pump is powered on, but the boiler supply sensor indicates that the water
temperature is too high to ignite. This is a temporary hold on the burner only and all other functions will
remain functioning properly. This error will clear itself when either the boiler supply temperature drops
below the BOILER SUPPLY minus boiler supply differential (5
o F) or DHW SETPOINT is satisfied and no
longer calls for heat.
Fault Code PRO
LOW WATER PRESS
PUMP OFF PRO
This display indicates that there is low water
pressure in the boiler. This code will reset
automatically after the water pressure is high
enough for the boiler to run safely. The second
line indicates the status of the pump. Note that
while the water pressure is low, the pump will be
off. 1. Assure that the system pressure is above 10
psig.
2. Check for leaks in the system piping.
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 boiler.
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.