Install Instructions

dHW SETPoInT ValuE addITIon
To achieve a boiler operating temperature during a domes-
tic request for heat the MCBA Control uses Parameter 1
and a second parameter, Parameter 21 DHW Setpoint
Value Addition. Parameter 1 plus Parameter 21 will estab-
lish the boiler operating temperature.
dHW on dIffEREnTIal
The MCBA Control Module has 2 differential settings for
the burner operation when using the IDWH Sensor kit.
The first differential setting the installer has the option of
adjusting is Parameter 38 “DHW ON Differential”. This
parameter sets the DHW storage temperature low limit.
The burner operation will respond when the DHW stor-
If Parameter 1 is set below 134 º F it is recommended that
Parameter 21 be reset to a higher setting. The request
for domestic heat is based on the temperature reading of
age temperature drops below
Parameter 38 setting.
Parameter 1 minus
the DHW sensor and its relationship to Parameter 1.
The boiler temperature setpoint is based on Parameter
1 plus Parameter 21 with a maximum operating temper-
ature of 194ºF.
A minimum “DHW ON Differential” parameter setting will
create a quicker burner operation response to any
domestic water draws from the domestic storage tank.
In contrast, a maximum “DHW ON Differential” setting
will result in a delayed response to domestic draws.
To revise the parameter setting within the Prestige
Control Module for the DHW Setpoint Value Addition, the
installer must enter the access code for the control mod-
ule as previously described in the Program Access of the
MCBA section.
1. Enter the access code.
2. Once the access code has been entered and
accepted, press MODE until the display shows
PARA .
3. Press STEP until the display shows P_21 . This
parameter setting is the DHW Setpoint Value
Addition parameter. After releasing the STEP button
the display will show the current setting.
4. Press the + or - button until the desired “DHW
Setpoint Value” setting is achieved. Press STORE
to save the setting. The display will flash when the
revised setting is accepted.
5. Once the desired parameter setting have been
revised and stored within the Prestige Control mod-
ule, press RESET to exit the CODE mode.
16
DANGER
The “dHW on differential” setting of Parameter 38
greatly affects the production of domestic hot water.
a minimum setting of Parameter 38 could result in a
rapid response to a dHW request for heat resulting in
a potential scald hazard. It is strongly recommended
that the installer utilize a anti-scald thermostatic mix-
ing valve on the hot water outlet of the dHW storage
tank. failure to comply could result in severe per-
sonal injury, death or substantial property damage.
To revise the parameter setting within the Prestige
Control Module for “DHW ON Differential” control, the
installer must enter the access code for the control mod-
ule as previously described in the Program Access of the
MCBA section.
1. Enter the access code.
2. Once the access code has been entered and
accepted, press MODE until the display shows
PARA .
3. Press STEP until the display shows P_38 . This
parameter setting is the “DHW ON Differential”.
After releasing the STEP button the display will
show the current setting.