8
Parameter Adjustments
The first parameter adjustment for IDWH aquastat con-
trol application is Parameter 35. Follow the steps given
in Program Access Section on page 2 until the display
shows
P_35
. Release the STEP button and thedisplay
should show the factory setting list below. Use the + or
- to adjust to the revised setting and press STORE to
save the setting. The display will flash when the setting
is stored in the MCBA control.
Parameter 35 has multiple parameter settings
available in addition to the settings 12 and 13. DO
NOT set Parameter 35 to any other setting other
than 12 or 13. Failure to comply can result in
erratic or unreliable operation of the Prestige
Boiler.
The next parameter adjustment for this application is
Parameter 1 and Parameter 33. Parameter 1 is acces-
sible during normal operation and does not require entry
into the CODE mode. To exit the CODE mode, press
the RESET button once.
Parameter 1 and Parameter 33 combine to create the
boiler operating temperature limit during a heat request
for DHW. The operation of the burner on/off is con-
trolled by the IDWH aquastat. The modulation of the
burner is based on the current boiler temperature and
its relationship to the temperature limit established by
Parameter 1 plus Parameter 33.
If Parameter 1 is set below 134ºF then it is recom-
mended that Parameter 33 be reset to a higher setting.
The request for heat is based on the DHW aquastat
closing an end switch which is connected directly to the
24V low voltage terminal of the Prestige. The operating
temperature set point of the Prestige boiler is based on
Parameter 1 + Parameter 33 with a maximum operating
temperature of 194ºF. The burner modulation is based
on the relationship of the boiler supply temperature and
the sum of Parameter 1 and Parameter 33.
WARNING
The “Detection OFF” setting of Parameter 27
greatly affects the production of domestic hot
water. A maximum setting of Parameter 27 could
result in excessive domestic storage tempera-
ture resulting in a potential scald hazard. It is
strongly recommended that the installer utilize a
thermostatic mixing valve on the hot water out-
let of the DHW storage tank. Failure to comply
could result in severe personal injury, death or
substantial property damage.
To adjust DHW NTC sensor differential “DETECTION
OFF” value follow the steps given in Program Access
Section on Page 2 until the display shows
P_27
.
Release the STEP button and the display should show
the factory setting. Use the + or - to adjust to the revised
setting and press STORE to save the setting. The dis-
play setting will flash when the setting is stored within the
MCBA control
FROST / FREEZE PROTECTION OF THE
IDWH
This feature is only available when the storage tank tem-
perature is controlled by a NTC sensor. If the NTC sen-
sor senses a domestic storage tank temperature of 38
º
F
then the Prestige will active the DHW burner and circu-
lator function. The burner will operate at minimum input
rate and the circulator will energize until the NTC sensor
senses 50
º
F. At that point the boiler will shut off the
DHW burner function and DHW circulator. This feature
is always active even if the DHW operation is placed into
an OFF mode (See Parameter 2 DHW Burner /
Circulator Function Setup, page 9).
DOMESTIC HOT WATER (SMART OR TR
SERIES) WITH AQUASTAT CONTROL
This application is the standard factory setup of the
MCBA control. In this application the Prestige uses the
aquastat of the SMART or TR Series Indirect Fired
Water Heaters to initiate a request for heat.
DANGER
Parameter
Factory Setting
Revised Setting
P_35
13
13
Parameter
Factory
Default Setting
Minimum
Setting
Maximum
Setting
1
140ºF
68ºF
148ºF
Parameter
Factory
Setting
Minimum
Setting
Maximum
Setting
P_27
18ºF
(-)16ºF
54ºF
