Water Line Connections; Heater Wiring - A.O. Smith BTH 120-250(A) Installation & Operating Instructions Manual

WATER LINE CONNECTIONS

This manual provides detailed installation diagrams (see back section of
this manual) for typical methods of application for the water heaters.
The water heater may be installed by itself, or with a separate storage
tank.
CLOSED SYSTEM
A closed system will exist if a check valve (without bypass),
pressure reducing valve (without bypass), or a water meter
(without bypass) is installed in the cold water line between the
water heater and street main (or well).
Excessive pressure may develop causing premature tank failure or
intermittent relief valve operation. This type of failure is not covered by the
limited warranty. An expansion tank or a similar device may be required in
the inlet supply line between the appliance and the meter or valve to
compensate for the thermal expansion of water under supply pressure.
If a water heater is installed in a closed water system, check local codes
or contact the water supplier or local plumbing inspector on how to control
this situation.
WATER (POTABLE) HEATING AND SPACE HEATING
1. All piping components connected to this unit for space heating
applications shall be suitable for use with potable water.
2. Toxic chemicals, such as those used for boiler treatment, shall
NEVER be introduced into this system.
3. This unit may never be connected to any existing heating system or
component(s) previously used with non-potable water heating
appliance.
WHC1202 INTEGRATED WATER HEATER CONTROL CONNECTION DIAGRAM
CAUTION
4. When the system requires water for space heating at temperatures
higher than required for domestic water purposes, a tempering valve
must be installed. Please refer to installation diagrams on pages 23
through 28 in back of manual for suggested piping arrangements.
IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE APPLIANCE
MUST BE REPLACED, IT MUST BE REPLACED WITH 105°C OR ITS
EQUIVALENT, EXCEPT IN THE BURNER HOUSING. IN THIS CASE USE
200°C WIRE.
THE COMPUTER CONTROL REQUIRES A SOURCE OF STABLE CLEAN
ELECTRICITY FOR PROPER OPERATION. INSTALLING THE HEATER ON
A BRANCH CIRCUIT THAT HAS ELECTRONIC NOISE, IS SUBJECT TO
FLUCTUATIONS IN VOLTAGE LEVEL OR HAS AN APPLIANCE WHICH
GENERATES EMF OF RFI INTERFERENCE CAN CAUSE THE
CONTROLLER TO MALFUNCTION. A HIGH QUALITY POWER
CONDITIONER MUST BE INSTALLED IF THE ABOVE CONDITIONS EXIST.
MALFUNCTIONS CAUSED BY A POOR ELECTRICAL SUPPLY ARE NOT
COVERED UNDER YOUR WARRANTY.
The controller is wired to the heater as shown in figures 16 & 17. The
model and rating plate provides the electrical information needed to
size the complete heater branch supply.
All electrical work must be installed in accordance with the National
Electrical Code and local requirements.
When installed, the appliance must be electrically grounded in
accordance with local codes or, in the absence of local codes,
with the National Electrical Code , ANSI/NFPA 70 and/or the
CSA C22.1 Electrical Code.
DO NOT ENERGIZE THE BRANCH CIRCUIT BEFORE THE HEATER TANK
IS FILLED WITH WATER.
NOTE: This controller is Polarity Sensitive. If the Hot and Neutral
Supply Voltage is reversed, the controller will not sense flame.
Verify polarity before connecting the unit.
FIGURE 16
14

HEATER WIRING