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BMC and BMC-6X Installation and Operation Manual
SELECTING THE MODULATING MODE
Normal, Parallel
Button: MENU/<System Startup>/..../Modulating Mode
•
Some modulating boilers perform better as their modulation increases. For these
units, it is advantageous to run one unit at high modulation than several units at lower
modulation. If the units used are of this type, select Normal. This is the recommended
setting for typical steel and cast iron boilers or boilers with low turndown ratios.
•
There are many condensing boilers that run more efficiently at lower modulation. If it is more energy efficient to run several
units at lower modulation than one at high, select Parallel. This is typically used on water-tube boilers, low mass boilers, or
burners with high turndown ratios.
PROVE/DOMESTIC HOT WATER (DHW)
Prove, DHW Without Priority, DHW With Priority
Button: MENU/<System Startup>/..../Prove-DHW Sharing
•
Input Terminals 29 and 30 can be used with either of the above features.
•
When Prove is selected, the BMC will not start any boiler stage unless Prove terminals
are connected.
•
Using those terminals to connect to an aquastat for a Domestic Hot Water call and selecting either of the DHW options will
raise the calculated water temperature to the lower of 200°F or Max Water Temperature.
•
Domestic Hot Water Without Priority allows the SYS relay, mostly controlling a primary system pump, to remain energized
during a domestic hot water call (aquastat call on terminals 29 and 30). In Summer, Shutdown, No Tstat call for heat, or when
outdoor temperature is above Outdoor Cutoff, a DHW call will energize the SYS relay. After the DHW call termination, the
SYS relay will continue to run for the System Run-On period before turning off.
•
However, Domestic Hot Water With Priority de-energizes the SYS relay during a domestic hot water call (aquastat call on
terminals 29 and 30) for a period of one hour. If after the hour period the DHW call still exist, the SYS relay will energize and
the BMC will continue in the higher temperature setting until the domestic hot water call has terminated.
SHUTDOWN/TSTAT/SETBACK MODE
Shutdown Input, Tstate Input, Setback Input
Button: MENU/<System Startup>/..../Setback\Shutdown
•
The BMC has two levels of heat, a Normal/Day and a Setback/Night. The Normal is
good for when buildings are occupied and people are active. The Setback/Night holds a
lower system temperature and is for when buildings are unoccupied or inactive.
•
When Shutdown or Tstat are selected, the Day/Night Schedules (see page 21) will be available in the operating menu.
Terminals 31 and 32 will function as a Shutdown (Turn off boilers when shorted) or Tstat (Turn off boilers when opened) of the
heat functions. However, a call for DHW will bring the boilers on.
•
When Setback is selected, the External Signal option will switch the BMC to Setback mode when shorted on terminals 31 and
32. This allows the BMC to be managed by an external device or control to provide setback. No scheduling or boost menu
options will be available with Setback.
BOOST MODE (NOT AVAILABLE WITH SETBACK)
30 Minutes, Disabled
Button: MENU/<System Startup>/..../Boost Mode
•
If you do not want a Boost simply select Disabled from the Boost Menu.
•
Boost is only available if Shutdown or Tstat is selected as a previous option.
•
The morning Boost is designed to return the building to comfortable ambient temperatures after the cooler Night (Setback)
period. The BMC will accomplish this by running elevated water temperatures (will add Setback setting to calculated water
temperature) for 30 minutes before the start of the Day schedule setting. That is, if the normal day set point at a specific outdoor
was 145˚F and the Setback setting was 20˚F, the boost will raise the system calculated temperature to 165˚F for 30 minutes
before the start of the Day Schedule setting.
Default: Normal
Default: Prove
Default: Shutdown Input
Default: 30 Minutes
------ MODULATION MODE ------
Normal
Parallel
BACK
----- PROVE/DHW SHARING ----
Prove
DHW Without Priority
DHW With Priority
BACK
----- SETBACK/SHUTDOWN -----
Shutdown Input
Tstat Input
Setback Input
BACK
---------- BOOST MODE ---------
30 Minutes
Disabled
BACK
SAVE
SAVE
SAVE
SAVE
15
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