General Requirements; Required Ability; Location; Replacing Existing Common Vented Boiler - A.O. Smith HW 300 Instruction Manual

REQUIRED ABILITY

Installation or service of this boiler requires ability equivalent
to that of a qualified service technician in the field involved.
Plumbing, air supply, venting, gas supply, and electrical work are
re quired.

LOCATION

When installing the boiler, consideration must be given to proper
location. The location selected should provide ade quate air
supply and be as centralized with the piping system as possible.
This location should also be such that the gas ignition system
components are protected from water dripping, spraying,
etc.) during boiler operation and service (circulating pump
replacement, control replacement, etc.).
Some local codes permit operation of gas appliances if installed 18
inches or more above the floor. This may reduce the risk if location in
such an area cannot be avoided.
A hot water boiler installed above radiation level or as required by
the authority having jurisdiction, must be provided with a low water
cutoff device at the time of boiler installation.

GENERAL REQUIREMENTS

15

REPLACING ExISTING COMMON VENTED BOILER

When an existing boiler is removed from a common venting
system, the common venting system is likely to be too large
for proper venting of the appliances remaining connected to it.
At the time of removal of an existing boiler, the following steps
shall be followed with each appliance remaining connected to
the common venting system placed in operation, while the other
appliances remaining connected to the common venting system
are not in operation.
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion and other deficiencies which
could cause an unsafe condition.
3. Insofar as is practical, close all building doors and windows
and all doors between the space in which the appliances
remaining connected to the common venting system are
located and other spaces of the building. Turn on clothes
dryers and any appliance not connected to the common
venting system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they will operate at
maximum speed. Do not operate a summer exhaust fan.
Close fireplace dampers.
4. Place in operation the appliance being inspected. Follow
the lighting instructions. Adjust thermostat so appliance will
operate continuously.
5. Test for spillage at the draft hood relief opening after 5
minutes of main burner operation. Use the flame of a match
or candle, or smoke from a cigarette, cigar or pipe.
6. After it has been determined that each appliance remaining
connected to the common venting system properly vents
when tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas-burning
appliance to their previous condition of use.
7. Any improper operation of the common venting system should
be corrected so the installation conforms with the National
Fuel Gas Code, ANSI Z223.1/NFPA 54 and/or CSA B149.1,
Installation Codes. When resizing any portion of the common
venting system, the common venting system should be
resized to approach the minimum size as determined using
the appropriate tables in the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 and/or CSA B149 .1, Installation Codes.