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P/N 42-9472 Copyright 2008 Mestek, Inc.
Cast iron condensing boiler
Cast iron condensing boiler
— Control manual
Menu item
Under . . .
Explanation
MOD MAX-LAST
ADVANCED SETUP
MODULAR BOILER
This sets the maximum fi ring percentage for boilers during times that some boilers are not fi ring.
It limits input of the boilers to keep them as effi
cient as possible. Once all boilers are started
(during high heat demand periods), this limit is remove, and all boilers can fi re up to maximum
input. Once any boiler is dropped offl
ine, the limit is applied again.
STOP BAND OFSET
ADVANCED SETUP
MODULAR BOILER
This setting helps reduce short-cycling when water temperature is within the heat band. If the
water temperature rises to the top of the heat band less the STOP BAND OFFSET before a boiler
just added has completed its modulation delay time, the boiler will shut down. Example, if the
top of the heat band is 190°F and stop band off set is 15°F, a newly-added boiler will shut down if
the temperature reaches 175°F (190 - 15) before its modulation delay time has ended.
BLR START TIME
ADVANCED SETUP
MODULAR BOILER
DO NOT CHANGE — This is the time from receiving a call for heat to when a boiler begins its
modulation operation (running at minimum fi re).
(P)ROPOR =
ADVANCED SETUP
MODULATION PID
This parameter should generally be left at factory default.
(I)NTEGRAL =
ADVANCED SETUP
MODULATION PID
This parameter should generally be left at factory default.
(D)ERIVAT =
ADVANCED SETUP
MODULATION PID
This parameter should generally be left at factory default.
BAND
ADVANCED SETUP
MODULATION PID
This parameter should generally be left at factory default.
ROTATION
ADVANCED SETUP
FIRING MODE
Select the rotation method. True rotation attempts to fi re all boilers an equal amount of time.
First on/fi rst off jogs between boilers to balance usage. Last on/fi rst off maintains the same
rotation sequence at all times.
MASTER 1ST
ADVANCED SETUP
FIRING MODE
Set this to “ON” to always start the master boiler fi rst, regardless of the rotation scheme selected.
SENSOR#
ADVANCED SETUP
SENSORS
There are up to three sensors: OUTSIDE, HEADER and RETURN.
TYPE
ADVANCED SETUP
SENSORS
Type Z is for a thermistors sensor (as supplied by Mestek).
“None” means do not use this sensor.
ON/OFF looks for an external dry contact closure.
CALIBRATE ?
ADVANCED SETUP
SENSORS
Use this function only if the response to a sensor indicates the control calibration may be off .
Calibrate the control by attaching a 10k precision resistor across the sensor terminals.
Select “YES” after “CALIBRATE ?.”
The control will measure the resistance and establish a trim value (in ohms) for the sensor input.
The control display will show the trim value setting.
The trim value must not /- 200 ohms. If it does, verify that the resistor is correctly
connected. If so, the sensor input is bad. Contact Mestek for recommended action.
If the trim setting is acceptable, press the SELECT key to accept.
The display will show, “TRIM VALUE SET!”
After a slight delay, the display will return to the sensors menu.
CHANGE PASSWORD
ADVANCED SETUP
PASSWORD
Use to set/change a password.
Table 8
Setup menus — parameter explanations (continued)
Control menus and adjustments
(continued)
4
