MACH
®
Gas Fired Boiler
10
Bumping hazard from overhead ducts! Install all components with adequate
vertical clearances.
3.4
E
LECTRICAL
C
ONNECTIONS
The boiler is wired for 120 volts, single phase, 60
hertz. The total operating amperage is indicated on
the rating nameplate. MACH
®
boiler units
C750/C900/C1050 require less than 8 amps. Before
starting the boiler, check to ensure that the proper
electrical service is connected to the boiler.
An external electrical disconnect (not supplied with
the boiler) with 15 amp overload protection is
required. The boiler must be grounded in
accordance with local codes or in the absence of
such requirements, in the U.S. with National
Electrical Codes, ANSI/NFPA No. 70 latest edition
and in Canada to the current Canadian Electrical
Code, Part I, CSA C22.1.
NOTICE! A dedicated earth ground (green
wire) is required to avoid nuisance
shutdowns.
Do not ground through the conduit. It is also
important that proper polarity be maintained.
The electrical boxes are located on the top rear of
the boiler. For wiring details, refer to Terminal Block
Assignments in section 6.1
3.4.1 High Voltage (TB2) Terminal Block
The boiler power circuit requires 120 VAC, 60 hertz,
with a dedicated neutral and ground as labeled.
Electrical service must be rated for 8 amps
minimum. Before starting the boiler, check to ensure
that the proper voltage and amperage are connected to the boiler and that the boiler is connected to a suitable fused
disconnect switch or circuit breaker. There must be less than 1.0V from Neutral (TB2-3) to Ground (TB2-8)
120VAC Switched Output
- This contact closes when the boiler is switched on. This provides 120VAC 5Amp service
to TB2-10. The neutral for this circuit is provided on TB2-3. When the boiler is switched off, this terminal is switched
off as well.
3 Way Valve-
This output is normally energized, keeping the three way valve providing heat to the building. The
Domestic Hot Water (DHW) call for heat de-energizes this circuit, causing the 3 way valve to self close, thereby
providing heat to the DHW loop. This output provides 120VAC 0.5Amp service to TB2-11. The neutral for this circuit
is provided on TB2-4.
DHW Pump Relay w/Delay Off
- This output is enabled when there is a call for DHW. When the call for heat is
removed, the output remains enabled for a period of time. This output provides 120VAC 0.5Amp service to TB2-12.
The neutral for this circuit is provided on TB2-5.
TB 1 LV (24 VAC)
TB 2 HV (120VAC)