Weil-McLain BMC Boiler User Manual


 
17
BMC and BMC-6X Installation and Operation Manual
OPERATING SETTINGS
PROGRAM CHANGE SETTINGS
To be able to change the BMC settings the Program/Run Switch must be set to Program. The
switch is located under the Enclosure Wiring Cover for security. The Enclosure Wiring Cover
can be securely closed using a lock.
RUNPROGRAM
BACK SAVE
------------- SEASON --------------
Winter
Summer
ALERT
DO NOT turn power off to the
BMC when heating season is
over. If you do so, the battery
will run down and will have to
be replaced. Instead, switch to
Summer.
SEASON
Winter, Summer Default: Winter
Button: MENU/Season
The BMC will turn all boiler relays off when it is in Summer setting. However, a DHW
call will bring boilers back on if needed. The Message Display Line will display Summer
to show status.
When in Winter, the BMC will activate the Sys relay whenever the Outdoor temperature
(OD) falls to or below the Outdoor Cutoff setting. In addition, it will begin heating
whenever the System temperature (SYS) falls below the Set Point Temperature. The
Message Display Line will not display any season information when in Winter.
When the heating season is over, it is a good practice to switch the BMC to Summer
setting. This will allow DHW calls to operate the boilers when needed.
SET POINT (NOT ADJUSTABLE IN EMS MODE)
Adjustable from 70ºF/ 21ºC to 250ºF/ 121ºC Default: 140ºF/ 60ºC
Button: MENU/Set Point
The Set point is the temperature value the BMC will use to control the system.
It only be available when Set Point is selected as the Sensor Type. See page 14.
The BMC will increase, decrease or hold the modulation of the boilers to maintain the
system temperature around the Set point. The amount of fluctuate around the set point
depends on the Modulation Mode, System Settings, and Stage Settings.
If the EMS Mode was Enabled, the Set Point will be set by the EMS/BMS system and
will be available to be read but not changed on the display.
BACK SAVE
------------ SET POINT ----------
70 F
[]
RESET RATIO
Adjustable 1.00ºOD : 4.00ºSys to 4.00ºOD : 1.00ºSys Default: 1.00ºOD : 1.00ºSys
Button: MENU/Set Point
It's only be available when Reset is selected as the Sensor Type. See page 14.
The Reset Ratio determines how the System water temperature (SYS) will vary with
Outside temperature (OD). With any of the ratios, the colder it becomes outside,
the hotter the temperature of the system water. The ratios are adjustable from 1.00
(OD):4.00 (SYS) to 4.00 (OD):1.00 (SYS). (See Understanding Operation Concept on
page 5)
With a 1.00 (OD):4.00 (SYS) ratio, the System water temperature (SYS) will increase
rapidly as the outside temperature falls, hitting the maximum of 240°F at 24°F outside
temperature. With a 4.00 (OD):1.00 (SYS) ratio, the System water temperature (SYS)
will increase slowly as the outside temperature falls. Even at -30°F, the system water
--------- RESET RATIO ----------
1.00 OD=4.00 Sys
1.00 OD=3.00 Sys
1.00 OD=2.00 Sys
1.00 OD=1.50 Sys
1.00 OD=1.25 Sys
1.00 OD=1.00 Sys
1.25 OD=1.00 Sys
1.50 OD=1.00 Sys
2.00 OD=1.00 Sys
3.00 OD=1.00 Sys
4.00 OD=1.00 Sys
BACK SAVE
will only be 125°F, and at 24°F outside, the system water will be 112°F. Such a low
Reset Ratio might be used with radiant floor heating applications.
With most baseboard heating applications, a 1.00 (OD):1.00 (SYS) setting is a good
place to start. With a 1.00 (OD):1.00 (SYS) ratio, for every degree the outside
temperature falls, the system water temperature is increased one degree.
If required: Adjust the RESET RATIO in cold weather. If the ambient building
temperatures are too cold in cold weather, move the ratio to a higher selection. That is,
if 1.00 (OD):1.00 (SYS) was initially selected, change the selection to 1.00 (OD):1.25
(SYS). If the building temperatures are too warm in cold weather, move the ratio to
a lower selection. That is, if 1.00 (OD):1.00 (SYS) was initially selected, change the
selection to 1.25 (OD):1.00 (SYS).
Outdoor Temperature
Water Temperature
70 405060
130
120
110
100
1:4 1:1
4:1
Colder
Warmer