42
8.3 Access To Connection Block
1.
Ensure there is no line voltage at boiler.
2.
Unscrew two screws located under front panel. Remove
front cover.
3.
Guide controller or thermostat wire through round
grommet(s) on right side of boiler's bottom plate right.
4.
Tilt control box forward by opening holding clips located
on left side of boiler.
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 is fully engaged.
9.
Replace front cover and screws under front panel.
10.
Turn power to boiler on.
Various thermostats and controllers can be connected to
standard control PCB.
8.4 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.
FIGURE 8-2 Terminal Block Locations
Fuse Holders (2)
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.
!
TERMINAL BLOCK M2
Terminals 1 - 2:
bus connection of programmable room unit
(supplied as accessory)
Terminals 4 - 5:
outdoor temperature sensor connection
(supplied as accessory)
Terminal 3 :
not used.
Terminals 6 - 7 - 8:
see section 8.6.
Terminals 9 - 10:
Indirect storage tank sensor connection
for GMHB227 and GMHB380 models.
FIGURE 8-3 Terminal Plastic Cover with Knockouts
Remove
New Opening
PN 240012369, REV A [08/31/2018]
8 - ELECTRICAL CONNECTIONS
