Bock Water heaters ezFIT Installation And Operation Instruction Manual page 5

VENTING
The water heater shall be located as close to the chimney as practical. Long lateral runs will
result in intermittent combustion problems and unsafe operating conditions. Total vent
height should be a minimum of 6 feet. Shorter vent heights could result in unstable draft and
nuisance lock outs.
The venting system should be sized according to National Fuel Gas Code: NFPA 54/ANSI
Z223.1 (most recent edition) using the "Natural" column. If you do not have a copy of this
code one can be obtained at www.NFPA.org for a nominal fee. Copies of the NFPA venting ta-
bles are also reprinted in the Bock Engineering Manual available from your Bock Representa-
tive or download from www.bockwaterheaters.com. Note: Do not reduce vent size more than
one size smaller than the vent connector supplied with the heater. If vent size must be reduced
one size, use full size vent connectors on the vent hood and reduce vent size as far from the
water heater as practical. B vent, L vent or multi-fuel venting may be used. Vent tables sup-
plied by the vent manufacturer may also be used in sizing the vent system.
Venting system must be capable of producing –0.02" WC (inches of water column) draft mini-
mum. If draft of –0.02" WC cannot be produced with an existing vent system, a draft inducer
may be required. Installations common vented with large vent hood equipped appliances such
as heating boilers may require vent dampers on the heating boiler connectors for proper vent
operation during no-heating season.
Check the building for items that can cause severe negative pressure problems such as large
exhaust fans. If these devices are installed in the same building check for their effect on draft
and combustion. All fuel burning appliances must be isolated from the effects of these devices
to operate properly. Failure to address this issue will result in unsafe operation and shorten
appliance life spans.
Your Bock water heater may also be operated with a power venter. The power venter must be
properly sized and adjusted to provide proper draft. Power venter wiring must turn on the
power venter on a call for heat and must prove venter operation before allowing the burner to
start. Refer to the power venter instructions for proper wiring and adjustment procedures.
Power vent terminal clearances must comply with local codes or the latest edition of NFPA
54/ANSI Z223.1 or CSA B149. See Figure 3 and Table 2 for required clearances.
Power Vent Terminal Clearances
Figure 3:
Atmospheric Gas Page 5