Navien NCB-24LSWE, Service Manual

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NCB Service Manual 49 Version 1.0
Item Description Display
(I) Anti-fast
cycling time
The anti-fast cycling time is the duration that the boiler stops space
heating when the supply or return temperatures reach the set
temperatures. The boiler will not resume heating until the duration
elapses even if the space heating supply or return temperatures return to
within the set range.
Range Default
0 to 20 minutes 3 minutes
Eg.) Anti-fast cycling set
at 3 minutes
(J) CH Pump
overrun
time
The pump overrun time is the duration that the circulation pump will
continue to run when the space heating supply or return temperatures
reach the set values. The boiler stops operating, the burner turns off, and
the circulation pump runs. If the space heating supply or return
temperature is outside the boiler’s operating temperature range after
the set time, the circulation pump stops for 10 minutes, runs again for 5
minutes, and then repeats the cycle.
Range Default
3 to 40 minutes 40 minutes
Eg.) CH pump overrun
set at 40 minutes
(K) Maximum
DHW
capacity
This menu configures the desired DHW capacity. When the boiler
operates in <Normal operation mode>, the maximum DHW capacity is
limited to the set value (%).
Range Default
(DHW minimum temperature set point + 20%)
to 100%
100 %
If maximum DHW
capacity is 100%.
(L) Minimum
DHW
capacity
This menu configures the desired DHW capacity. When the boiler
operates in <Normal operation mode>, the minimum DHW capacity is
limited to the set value (%).
Range Default
DHW minimum heat capacity to (DHW
maximum heat capacity - 20%]
DHW
minimum
capacity (%)
If minimum DHW
capacity is 25%.
(M) DHW wait
time
The DHW wait time is the duration that the boiler continues to operate in
DHW supply mode after DHW demand has been supplied. When DHW
wait time is enabled, a faster DHW time may be available if there is
subsequent demand for DHW. The boiler adjusts the 3-way valve for to
space heating mode when the set time elapses.
Range Default
0 to 20 minutes 5 minutes
If DHW wait time is set at
5 minutes.