1
Service
(continued)
17
Maximum Cascade Set Point
This parameter determines the set point used by the individual
water heaters in a Cascade. When a water heater is commanded
to fire by the Leader water heater, it will attempt to achieve
this temperature at its outlet. The Leader water heater will
limit the modulation of the water heaters in order to hold the
temperature at the tank sensor to the user set point. If any of the
water heater outlet temperatures reach the maximum cascade
set point, the water heater will then modulate down on its own
in order to keep its outlet temperature within the maximum
cascade set point. Therefore, this parameter can be used to limit
the outlet temperatures of all the water heaters in a Cascade.
This parameter is adjustable by the installer by accessing the
Maximum Cascade Set Point
parameter
.
The temperature range
of this parameter is 32° (0°C) to 190°F (88°C).
The default
maximum cascade set point is 185°F (85°C).
Minimum On/Off Time
In order to prevent units in a Cascade from short cycling,
this parameter defines the minimum ON and OFF time for
each unit. The installer can adjust this time by accessing the
Minimum On/Off Time
parameter. The minimum setting is 0
seconds and the maximum setting is 10 minutes. The default
is 30 seconds.
Minimum Next On Time
In order to reduce the risk of temperature overshoot with a
Cascade, this parameter defines the minimum time delay from
starting one unit until the next unit may be started. The installer
can adjust this time delay by accessing the
Minimum Next On
Time
parameter. The minimum setting is 0 minutes and the
maximum setting is 10 minutes. The default is 60 seconds.
Boiler Size
When water heaters of different sizes are connected together in
a Cascade, the Leader boiler has to know the size of each boiler
in that Cascade. The
Boiler Size
parameters allow the installer
to program the sizes based on the Cascade address. This screen
shows the Cascade address and the size of the boiler with that
address (in BTU/hr):
1. When the Water Heater Size screen is first accessed, Cascade
Address 0 (Leader) is shown.
2. Press the NAVIGATION dial to access the first digit of the
boiler size. Rotate the NAVIGATION dial to adjust the
first digit. To access the next digit, press the NAVIGATION
dial again. Continue this process until the correct boiler
size (to the nearest 1000 BTU/hr) is shown. Press the
RIGHT SELECT [SAVE] key.
3. Rotate the NAVIGATION dial to select the address of the
next boiler in the Cascade. Repeat Step 2.
4. Once the size of the last boiler in the Cascade has been
entered and saved, press the LEFT SELECT [EXIT] key to
return to the Control Modes menu.
5. If no other parameters are to be adjusted, press the RIGHT
SELECT [HOME] key to save the new settings and return
to the Status screens.
The SMART SYSTEM control automatically uses the Efficiency
Optimization Cascade type when controlling boilers of different
sizes.
Circulation pumps
DHW Pump Delay
The DHW pump delay parameter sets the length of time the
DHW pump (if connected) will run after a DHW demand has
been satisfied. This parameter is adjustable by the installer by
accessing the
DHW Pump Delay
parameter. The time range
for this parameter is 10 seconds to 40 minutes. The default
time is 1 minute.
DHW Pump Anti-Seize Delay
If the water heater pump does not run for 24 hours, it will
be turned on briefly to prevent it from seizing. The length
of time it runs is determined by the
DHW Pump Anti-Seize
Delay
parameter. The range of this setting is 0 seconds to 50
minutes. The default setting is 20 seconds.
BMS
BMS Type
When programmed for BMS control through the 0 - 10V
BMS input or through ModBus, the 0 - 10V signal can be
interpreted as either a modulation command or a set point.
When the
BMS Type
parameter is set to POWER, the 0 - 10V
signal will control the modulation. When set to SETPOINT,
the 0 - 10V signal will control the tank set point. The default
setting is SETPOINT.
Volts at Minimum
When programmed for BMS control through the 0 - 10V
BMS input or through ModBus, the
Volts at Minimum
parameter should be set to the minimum voltage signal sent
to the SMART SYSTEM control. The range of this parameter
is 0.0V to the
Volts at Maximum
value. The default setting
is 2.0V.
Volts at Maximum
When programmed for BMS control through the 0 - 10V
BMS input or through ModBus, the
Volts at Maximum
parameter should be set to the maximum voltage signal sent
to the SMART SYSTEM control. The range of this parameter
is the
Volts at Minimum
value to 10.0V. The default value is
10.0V.
Rate at Minimum Volts
When programmed for BMS control through the 0 - 10V
BMS input or through ModBus and the BMS Type is
programmed as POWER, the modulation percentage
represented by the
Volts at Minimum
parameter is set by the
Rate at Minimum Volts
parameter. The minimum value is
0% and the maximum is the Rate at Maximum Volts setting.
The default value is 20%.
Outdoor Armor Water Heater Service Manual
Содержание Knight 151
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