12
ADJUSTING DRAFT
Reference the heater manufacturer's instructions for its specified draft range and for where the draft should be sampled. In gen-
eral, most heaters will operate efficiently with a draft of -0.02 to -0.05" w.c. measured in the vent riser between the flue outlet and
barometric draft control (if present). The MPCI has a default draft set point of -0.10" w.c. This vent manifold pressure may need to
be adjusted up or down to meet the draft requirements of the interlocked heating equipment.
Do not
reduce set point to less than
0.07” w.c. to avoid issues with the PSA-1 operating range.
BALANCING DRAFT OF HEATERS
1. Turn ON the service switch to all of the heaters.
2. Momentarily cycle each heater to verify that the Amber Burner Status Call LED on the UC1 or MAC-Series interlock
control illuminates for each heater. If not, verify that wiring conforms to appropriate heater interlock wiring diagram.
3. Verify that all balancing baffles or blast gates are in the closed position. Adjust barometric controls (if present) to the most
closed position.
4. Fire each heater individually, starting with the heater farthest from the Exhaust / Supply Air Fan. Slowly open balancing baffle or
blast gate until the specified draft is achieved. Barometric draft controls should be closed when the heater is operating within its
specified draft range. Adjust weight on barometric draft control so that it does not open until the manufacturer’s recommended
maximum draft is reached. If additional draft is needed increase the set point on the MPCI.
5. After adjusting draft levels on all connected heaters, fire heaters in random order and simultaneously to verify draft levels remain
within the manufacturer’s specified range prior to ignition and during operation.
CHANGING MPCI PRESSURE CONTROL PROGRAM DEFAULTS
THE FACTORY PRESET PROGRAM SETTINGS ARE AS FOLLOWS:
PROGRAM OPTION
FACTORY PRESETS
ADJUSTMENT RANGE
Pressure Units of Measure
Units InH2O
Units PA
Operating Mode
Control Mode
Do Not Change
Parameter
Diff. Pressure
Do Not Change
Setpoint 1 (Use for Draft)
0.10
0 to 40 (PA 0 to 100)*
Setpoint 2 (Use for Supply/Comb Air)
0
0 to 40 (PA 0 to 100)*
*
NOTE:
A negative value can not be set on the Pressure Control, however, the Pressure Control can display a negative
pressure reading. Pressure Control will read either negative or positive pressures depending on what sensing port is used
and type of application. See “Sample and Reference Pressure Connections”, Page 2.
Output Voltage
V=10.0 V
Do Not Change
P-Parameter
50
1-999 (Acceleration Rate)
I-Parameter
3.15
Do Not Change
Controlling Mode
Positive/Heating
Do Not Change
Alarm Delay Time
10s
1 Second to 15 Minutes
The MPCI Pressure Control must be powered to enter the program mode.
WARNING:
Disrupt supply power to MPCI when remov-
ing and reconnecting wire from UC1 MTR terminal. With supply power OFF, remove wire from MTR on the bottom of the integral
UC1 Interlock Control and connect to the XL terminal of UC1. Reestablish power to MPCI and push the Pressure Control left but-
ton (T1), make any necessary program changes and cycle through the remaining programs by pushing the T2 button until the dis-
play reads MENU. Remove supply power to MPCI and remove lead from XL on UC1 and reconnect to MTR. Reestablish supply
power to MPCI.
To enable the SET POINT 2 for supply/combustion air a jumper wire must be installed between the last two terminals 8 & 9 on the
right hand side or the Pressure Control. See “Supply Make-Up / Combustion Air Pressure Set Point”, Page 5.