TFTN 085-199 Installation and Operation Manual
85
Table 16-9 Cascade Setup
(…Continued)
Setting
1
Parameter
2
Range/Description
Factory Setting
DHW Mode
(Cascade)*
25.2.2
Applicable to an IWH that is installed downstream (system side) of the
hydraulic separator, which is serviced by the entire cascade. Set as CH
Only if there isn't a downstream IWH serviced by the entire cascade.
CH Only
–
cascade system will not service the DHW request.
Tank Sensor
–
cascade manager is expecting a temperature sensor
reading from a Downstream IWH.
Aquastat
–
cascade manager is expecting an on/off switch input from a
Downstream IWH located
CH Only
DHW Max
Power*
25.0.1
Establishes the maximum power the total cascade will operate at for
DHW demands.
100%
Burner Run
Hours
Harmonization
24.9.4/
26…32.9.4
Sets the burner run hours statistics to equal the average of the other
boilers in the cascade. Perform this function ONLY on the boiler where
the PCB has just been replaced. Settings is not applicable for Single
boilers.
No
Turnover
Logic*
25.0.2
Sets the power division algorithm for the cascade.
Min Off-On Switches
–
when more than one boiler is servicing the
demand, one is subtracted (switched off) when the required power is
less than the sum of the active boilers operating at the Min Turnover
Level. Generally results in a greater number of boilers operating at a
lower power level.
Max Power Division
–
when more than one boiler is servicing the
demand, one is subtracted (switched off) when the required power
could be achieved by one fewer boilers operating at or below the Max
Turnover Level. Generally, results in a fewer number of boilers
operating at a higher power level.
In each scenario a new boiler is added (switched on) when the required
power is greater than the sum of the active boilers operating at the
Max Turnover Level.
Min Off-On
Switches
Turnover
Hysteresis*
25.0.3
Sets the amount the required power level must drop below Min
Turnover Level before a boiler is switched off. See Min Turnover Level.
(Range = 0-20%)
2%
Min Turnover
Level*
25.0.4
Sets the minimum power level for multiple boilers operating together
in a cascade. If the required power is less than the sum of the active
boilers operating at the Min Turnover Level (less the Turnover
Hysteresis) a boiler is switched off. To avoid short cycling, ensure the
Min Turnover Level is set to less than half of the Max Turnover Level
setting. Only applicable when Turnover Logic = Min Off/On Switches.
(Range = 20-MaxTurnoverLevel)
35%
Max Turnover
Level*
25.0.5
Sets the maximum power level for operable boilers when not all boilers
in cascade are switched on. If the required power is greater than the
sum of the active boilers operating at the Max Turnover Level, then the
next boiler is switched on. (Range = MinTurnoverLevel-100%)
60%
Maximum
Boiler
Temperature*
25.0.6
Establishes the maximum permissible operating temperature for the
individual cascade boiler. Higher temperatures will cause the
individual boiler to switch off. (Range = 68-199°F)
199°F
Notes:
1.
Settings marked with an asterisk (*) are only applicable for the Manager boiler.
2.
The parameter number for some Follower boiler settings will begin with 26-32 (instead of 24 or 25); 26 for Follower
Boiler 1, 27 for Follower Boiler 2 and so on. Follo
wer boiler settings are available from the “NTI net” webapp, and
of the Manager boiler by entering the applicable parameter number.
