Prepare Boiler Location; Installations Must Follow These Codes; High Altitude Installations - Williamson-Thermoflo GWC-070 Manual

GWC -
gas fired water boiler

Prepare boiler location

Installations must follow these codes:

• Local, state, provincial, national codes, laws, regulations and ordinances.
• National Fuel Gas Code, ANSI Z223.1- latest edition.
• Standard for Controls and Safety Devices for Automatically Fired Boil-
ers, ANSI/ASME CSD-1, when required.
• National Electrical Code.
• For Canada only: B149.1 or B149.2 Installation Code and CSA C22.1
Canadian Electrical Code Part 1 and any local codes.
The GWC boiler gas manifold and controls met safe lighting and other
performance criteria when boiler underwent tests specified in ANSI Z21.13
— latest edition.
For the Commonwealth of Massachusetts, read and follow
the special instructions located on page 34 of this manual.
Install the boiler so control system components are
from dripping or spraying water or rain
Allowing these components to become wet could cause a
boiler failure, resulting in severe personal injury, death or
substantial property damage.

High altitude installations

GWC boiler controls automatically reduce input with increasing altitude.
See Figure 1 for estimated input at altitude as a percentage of sea level
input. Multiply the boiler sea level input by this percentage to obtain the
estimated high altitude input. Note that the length of the venting system
will also have a minor impact on input.
No modifications to the boiler should be necessary for installations up to
5,500 feet above sea level. For higher elevations, the air pressure switch
must be changed to a special high altitude switch. Refer to the high altitude
kit instructions, page 10. Note that the gas valve outlet pressure must be
checked (and adjusted if necessary) following instructions on page 60.
DO NOT sidewall vent DIRECT EXHAUST APPLICATIONS
at altitudes above 5,500 feet. Sidewall venting is only allowed
for
DIRECT VENT
altitudes above 5,500 feet.
Vent length also affects boiler input — the boiler automati-
cally derates to compensate for pressure loss through the vent.
See the derate values given in Figure 105, page 99. For high
altitude installations, multiply the % in Figure 1 times the
value shown in Figure 105 to determine input vs sea level.
Service clearances
When possible, install GWC boilers with clearances at least as large as shown
in Figure 2 for best service access.
Flooring
The GWC boiler is approved for installation on combustible flooring, but
must never be installed on carpeting.
Do not install boiler on carpeting even if foundation is used.
Fire can result, causing severe personal injury, death or sub-
stantial property damage.
6
— Boiler Manual
during operation.
applications (ducted combustion air) at
Estimated GWC input at altitude
Figure 1
Altitude
(feet)
1,000
2,000
3,000
4,000
5,000
5,500
6,000
7,000
8,000
9,000
protected
10,000
Service clearances (recommended)
Figure 2
% Sea level input
97
93
90
87
83
82
80
77
74
72
69
Part number 550-142-056/0411