HTP EFT-155 - Lockout Condition; Cascade System Programming

LP-387 Rev. 7.3.15
48
K. Lockout Condition
If any boilers, including the master boiler in the cascade system,
are in a lockout condition, the master control will recognize the
lockout condition and skip over the boiler in the ring sequence.
Each boiler in the cascade system is responsible for its own
safety functions. So, if any individual boiler control senses an
unsafe condition, it will extinguish the burner and, if necessary,
go to a lockout condition. In this way, every boiler in the system
has its individual safety controls intact and operational, even if
the ring of the boiler is under control of the master boiler.
In the event that the system sensor fails, all boilers in the system
will ignite simultaneously when there is a demand, and each
boiler will individually regulate ring rates to maintain the
master set point temperature (supply temperature set point +
dierential) at the individual supply sensors built into the boiler.
If this should happen, the master boiler will display an E03 fault
code, indicating that the supply sensor has failed.
L. Cascade System Programming
1. If the boiler is used alone, skip this section.
2. Programming the Master Boiler:
a. Make sure there is no demand for heat being supplied to
the boiler.
b. Apply power to the boiler.
c. Enter the system setting program navigation following
instructions in Part 10 of this manual.
d. Verify that cascade address function 15 is set to 0. This
makes the master boiler address 0. NOTE: The Master Boiler
MUST be addressed as 0.
e. Change Cascade Mode function 23 to 926 Boilrs. This
makes it the master boiler.
begin a demand sequence as described above. Once the boiler
ignites, the master boiler control will increase the ring rate
command to that boiler until the system sensor temperature is
at the set point temperature plus the dierential, or that boiler is
at high ring rate. If the command from the master boiler control
gets to the high ring rate of the follower boiler, but the system
sensor is below the required temperature, the master boiler
control will then tell the next boiler in the ring sequence to
begin its demand sequence. The master boiler control will then
begin to ramp up the ring rate command of that boiler. This
process will continue while there is a demand until all boilers in
the cascade system are at high re or the desired temperature of
the system sensor is reached. If the system sensor temperature
reaches tank set point and dierential before all boilers are at
high re, the master control will modulate the cascade command
signal to maintain the system sensor at set point and dierential
until the demand is complete. When the system sensor is equal
to the set point temperature, demand is complete, and the
master boiler control will extinguish all boilers that may be lit.
If the demand decreases, the ring rate command and amount
of boilers lit will decrease exactly opposite as described above.
Whenever the master boiler control needs to re a follower
boiler, it sends a ring rate command to that boiler. The follower
boiler will respond to the command until its supply sensor
temperature gets to be 5
o
F above the set point temperature plus
the dierential, at which point the individual boiler will modulate
on its own so as not to overheat. As a result, it is not uncommon
to see the cascade output at maximum but individual boilers
ring at less than their maximum ring rate.
f. Exit the installer menu.
NOTE: The temperature set point of the master must match
the follower boiler set point in order for the system to operate
properly.
3. Programming Follower Boilers:
NOTE: READ THE NOTES BELOW BEFORE
PROGRAMMING FOLLOWER BOILERS
• The boiler addressed as 1 will share its alarm output
with the master boiler.
• If one of the follower boilers has an indirect red water
heater connected to it, the address of this boiler must
be 2 or greater.
• It is recommended but not necessary to address boilers
in the order that they are wired.
• No two boilers can have the same address.
• It is not required to use all consecutive address
numbers. Example: In a 2 boiler system with an indirect
connected to the follower, the follower address would
be 2 (address 1 is not used).
a. Make sure there is no demand for heat being supplied to
the master boiler
b. Apply power to the follower boiler you are working on.
c. Enter system settings following instructions in Part 10
of this manual
d. Set cascade address parameter 15 to 1 for the rst
follower, 2 for the second follower, etc. depending on
which boiler you are programming based on the above
notes.
e. Change “CASCADE MODE” parameter to “926 BOILRS”.
This makes the boiler a follower boiler and enables all
data to be transferred between boilers as needed for the
system to function to full capability.
f. Exit the installer menu.
NOTE: The temperature set point of the follower must match
the master boiler set point in order for the system to operate
properly.