Control Modes; Bms Thermostat Input; Cascade Address; Cascade Type - Lochinvar ARMOR 151 - 801 Service Manual

When controlling the water heater through the 0 - 10V BMS
input or through ModBus, the water heater can be enabled
one of two ways. With parameter F1 set to ACTIVE, the
water heater will be enabled by closing the Tank Thermostat
input. With parameter F1 set to INACTIVE, the water
heater will be enabled by the voltage level on the 0 - 10V
input (in the case of 0 - 10V BMS control), or the
input value received through ModBus. The default value is
INACTIVE.
The set point or modulation of the water heater may be
controlled through the 0 - 10V BMS input or through
ModBus. When parameter F2 is set to INACTIVE, the 0 -
10V input will be ignored. When set to ACTIVE, the set
point or modulation will be controlled by the voltage on the
0 - 10V input (in the case of 0 - 10V BMS control), or the 0
- 10V input value received through ModBus. The default
value is INACTIVE.
When BMS is set to ACTIVE (see BMS Active / Inactive)
and the water heater is being controlled through ModBus,
set parameter F3 to ACTIVE. Otherwise, set the ModBus
parameter to INACTIVE. Note that the water heater can
still be monitored by ModBus with this parameter set to
INACTIVE. The default value is INACTIVE.
The ModBus T/O is the amount of time the unit controls
will wait to receive a communication string from the BMS
controller before reverting back to its own internal
parameters. This is used to prevent unwanted operation
should ModBus communication be lost. Therefore, the
ModBus commands need to be refreshed within this time
period. This parameter is adjustable by the installer by
accessing parameter F4. The default value is 10 seconds.
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The water heater designated as the Leader needs to be
programmed with address 0. All the Member water heaters
require addresses from 1 to 7, and the addresses must be
different for each Member. The addresses can be in any
order, regardless of the order in which the units are wired
together. This parameter is adjustable by the installer by
accessing parameter F5.
connected to the Leader water heater. The default address
0 - 10V
is 1.
If installing the water heaters in an existing system with
existing Armor water heaters with old style controls, the
new water heaters should be programmed as the Leader
and/or the higher number addresses.
There are two (2) options for the way a Cascade divides the
load between its heaters. The first is Lead/Lag, designated
at L/L in the menu. This method will modulate the last two
(2) water heaters only. When the last water heater reaches
100% and the calculated load is still increasing, it will start
the next water heater at 20% and reduce the previous water
heater to 80%. When the calculated load is decreasing and
the last water heater gets down to 20% fire, it will hold it
there and start lowering the firing rate on the next-to-last
water heater. When the next-to-last water heater reaches
20%, it will turn the last water heater off and raise the rate
of the next-to-last water heater to 40%, thus eliminating
the sudden drop in total output of the Cascade.
The other Cascade divider method is Efficiency
Optimization, designated as EFF in the menu. This method
is used, as the name implies, when it is desired to have the
most efficient system. When the first water heater reaches
a certain rate (default = 90%), it lowers its rate to 45% and
turns on the next water heater at 45%. The two (2) water
heaters then modulate at the same rate.
As the calculated load increases further and both water
heaters ramp up to 90%, it lowers the rate of the first two
(2) water heaters to 60% and brings the next water heater
on at 60%. The three (3) water heaters then modulate
together. As the calculated load decreases, the water heaters
will reach a lower threshold (default = 30%), at which time
the last water heater (the third in our example) will turn off
and the Cascade will increase the rates of the remaining
water heaters to provide the equivalent total output as
before ((3 x 30%) / 2 = 45% in our example).
Service Manual
The tank sensor must be