24
ELECTRICAL
CONNECTIONS
This boiler is normally wired for 120 Volts. The voltage
is indicated on the tie-in leads. Consult the wiring dia-
gram shipped with the boiler in the instruction packet.
The "TH" leads are for the remote tank control connec-
tion. 24 Volts are supplied to this connection through
the boiler transformer.
DO NOT attach line voltage to the "TH" leads on mod-
els 133-1826. Before starting boiler check to ensure
proper voltage to boiler and pump.
The boiler must be electrically grounded in accordance
with National Electrical Code ANSI/NFPA No 70.
NOTES:
1. Field install ground to inside of junction box.
2. If any of the original wire as supplied with the boil-
er must be replaced, it must be replaced with
105°C wire or its equivalent.
CAUTION:
Label all wires prior to disconnection
when servicing controls. Wiring errors can cause
improper and dangerous operation. Verify proper
operation after servicing.
DANGER - SHOCK HAZARD:
Make sure
electrical power to the heater is disconnected to
avoid potential serious injury or damage to
components.
Low Water Cut-Off (Optional)
The probe-type low water cut-off automatically shuts
down burner whenever water level drops below the
probe for more than 2 seconds. A 30-second time
delay prevents premature lockout due to temporary
conditions such as power failure or air pockets.
Fig. 35: Low Water Cut-Off
High and Low Gas Pressure
Switches (Optional)
These switches sense either high or low gas pres-
sures and automatically shut down burners if abnormal
pressures exist.
Fig. 36: Gas Pressure Switch
NOTE:
The High Gas Pressure Switch is standard
on Models 3001-4001
