Electrical Connections; Access To Connection Block; Main Supply Connection - UTICA BOILERS MAHF-165 Installation, Operation And Maintenance Manual

DANGER
!
Electrocution Hazard! HIGH VOLTAGE - Connections
in terminal block M1 are high voltage (120V / 60Hz).
Before making connections, verify appliance is
disconnected from power supply. Respect the input
polarity on terminal block M1: L (LINE) - N (NEUTRAL).
Failure to follow these instructions WILL result in death
or serious injury.

8.4 Access To Connection Block

1.
Ensure there is no line voltage at boiler.
2.
Lift and remove front cover. Remove screws (2) from
cover on junction box located on boiler's left side. Remove
junction box cover.
3.
Guide controller or thermostat wire through round
grommet(s) located in the junction box on boiler's left
side.
4.
Tilt control box forward by opening holding clip located on
left side of control housing.
5.
Expose M1 and M2 terminal blocks by removing screw
from plastic cover on left. See Figure 8-3.
6.
Remove plastic from channel in plastic cover. Run wires
through new opening.
7.
Connect wires to appropriate terminals on connection
block.
8.
Tilt control box back to original position. Ensure clip on
left side of control box is fully engaged.
9.
Replace front cover and cover to junction box.
10.
Turn power to boiler on.
Dry contact end switches from various manufacturers can be
attached to boiler control PCB.

8.5 Main Supply Connection

Main supply is connected to terminal block M1 which is high
voltage (120V / 60Hz).
Fuses, 3.15 A, are incorporated in the power supply terminal
block. To check or replace fuse pull out black fuse carrier.
TERMINAL BLOCK M1
(L) = Live (brown)
(N) = Neutral (light blue).
= Ground (yellow-green).
(1) (2) = contact for 120V Room Thermostat.
Place jumper back on terminals 1-2 of boiler terminal block
M1 if room thermostat is not used or if Remote Control is
not installed.

8 - ELECTRICAL CONNECTIONS

FIGURE 8-2 Terminal Block Locations
FIGURE 8-3 Terminal Plastic Cover with Knockouts
TERMINAL BLOCK M2
Terminals 1 - 2: Bus connection of Open Therm Gateway
for ECR programmable room unit thermostat (supplied as an
accessory)
Terminal 3 : not used on Combi units
Terminals 3 - 4: indirect storage tank sensor connection
for heat-only boilers
Terminal 4 - 5: outdoor temperature sensor connection
(supplied as an accessory)
Terminals 6 - 7 - 8: 24V room thermostat connection
Terminals 9 - 10: 0 - 10V connection
36
Fuse Holders (2)
Remove
New Opening
240012874 REV A, [01/31/2020]