35
NOTE: Under certain circumstances, a problem with the low
gas pressure switch (and/or high gas pressure switch on
CSD-1 models) may cause an error code of Circulation FAIL or
Inducor FAIL depending on when the failure occurred in the
cycle.
NOTE: Upon lockout, manually push the ENTER/RESET button
on the display board to restart the boiler.
IMPORTANT NOTES
If you experience trouble with your Legend unit, the best advice is
to start at the main power source and work forward. Here are
some hints to help you.
– Make sure the correct electrical connections are made to the
unit. The Legend 2000 requires a 120V, 60 Hz, 30 Amp. circuit
to function properly. The unit must be the only appliance on
this circuit.
– Make sure the gas line is sized properly. Having multiple
appliances on a single gas line can cause gas pressure
fluctuations and gas volume problems that can hinder
performance. See manual for correct sizing.
– Check the five important electrical connections to the unit.
(120V line, 120V neutral line, Ground, (2) Tank Probe or (2)
Thermostat connections.)
– If rough starting is a problem, concentrate on the air/gas
mixture. Make certain there is 3.5” W.C. of gas pressure at the
manifold. Adjust the blower speed on the blower until the
situation improves. If the unit is “howling”, blower speed
adjustment is often the answer.
– If a blower speed adjustment does not improve starting, verify
the gas and air orifice dimensions and/or pull the burner and
check for debris.
– If a system pump is added to the unit and run directly from the
control board, the maximum power rating of the motor should
not exceed 1 hp.
– The board is set to sense ignitor current once the ignitor is
energized. The sensing threshold is between 3.2 and 2.7
amps. If the unit’s ignitor is coming on, but the gas valves are
not opening, check the ohm rating of the ignitor. It must be
between 40 to 70 ohms. Allow the ignitor to cool before you
take the ohm reading.
– If the unit has progressed in the cycle but will not fire, check
the pressure switches. Check the DIA-SCAN II display and
see if any of the RED LED’s are lit to help you identify the
problem. If you notice that the IGNITOR CURRENT LED is
flashing, check the polarity of the transformer wires. Switch
the position of the 24V wires on the terminals.
– The LW units come set-up for the tank probe. If one wishes to
use an alternate 24V method of temperature control
(Honeywell, White Rodgers, etc.), the Red/Green wires must
be used and the J33 control board jumper must be removed.
Either the tank probe connection or the thermostat
connection is to be used, but not both.
See previous pages.
– The display defaults to the outlet water temperature under
normal circumstances. On LW models, however, the display
defaults to the tank probe temperature once the probe supplied
with the unit is connected to the control board.
– Set the unit’s automatic reset limit at least thirty 30°F (17°C)
above the tank temperature setting on hot water supply
applications. However, the temperature setting should not
exceed 210°F (99°C) for such applications.
– The unit has an adjustable Set-Pt Differential. The tank Probe’s
Set-Pt Differential is not adjustable and is fixed at 5°F (3°C).
– The display will only show the tank temperature when the tank
probe supplied with the unit is used. Alternate 24V temperature
controls (Honeywell, White Rodgers, etc.) will have to be set
manually.
– Once the system is set up and a system temperature is
determined, make sure the unit’s automatic reset limit does
not interfere with the tank probe’s function. If the Set-Point
differential of the unit is set too high, it may alter the system’s
intended target temperature.
– Under any failure code, the ENTER/RESET button on the
display must be pushed before the unit will function.
– It is recommended that intermittent post circulate pump modes
be used for maximum efficiency.
– The inlet water temperature must be 140°F (60°C) to prevent
heat exchanger damage (use by-pass kit supplied with this
unit).
– It is imperative that installation specification be adhered to
when working with the Legend 2000. Correct gas pipe sizing,
vent installation, and electrical connections are critical for the
unit to function effectively.
– On LW models, verify that the J33 PC board jumper is in place.
It may fall out during shipping. A replacement jumper is
provided with the unit.
– Do not use the tank probe provided with the unit for loop
temperature regulation if using an LW model in a hydronic
heating application. An alternate 24 volt control must be used.
– In a large system where the system pump exceeds the
maximum 1 hp rating, the pump cannot be powered directly
from the control board. Use the 120 Volt pump connections to
energize the coils of an external relay. Connect the power to
the pump through the contacts of the relay. The power for the
pump and the unit should be on separate breakers.
– Do not use the outlet water temperature control as the system
temperature regulation device on LB models. 24 Volt
connections are provided at the rear of the unit for a thermostat,
aquastat, etc. The outlet temperature control should only be
used as a limit for the system temperature control. The system
temperature control should be located in the return loop of the
hydronic system.
5621 W. 115TH STREET, ALSIP, IL 60803
Phone: 800-433-2545 Fax: 800-433-2515
www.aosmithwaterheaters.com
E-mail: [email protected]
Summary of Contents for LB 1000
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