Overview of Primary Product

page 8
AIR FLOW ADJUSTMENTS
In order to obtain proper system draft, the power venter has an air ow adjustment
damper built in. When used in a system with a barometric draft control, this damper
should be used to make coarse draft adjustments, while the barometric should be used
for  ner adjustments. Loosen the locking screw on the air  ow adjustment damper
on the outer pipe of the power venter. (See Figure 11) Adjust the damper to the full
open position. Follow appliance manufacturer’s procedures for starting the heating
appliance. Then adjust the thermostat to call for “Heat”. After the system has operated
for several minutes to stabilize  ue gas temperatures, check for negative draft or up-
draft at the heating appliance outlet or air  ow into the draft hood. Use a draft gauge,
velocity meter or match test procedure. Adjust the adjustment damper closed to obtain
the minimum air  ow required to maintain draft. Then increase air  ow slightly (10%
over minimum air  ow rate) to ensure proper venting. For oil- red or gas- red power
burners, adjust draft to proper over- red draft.
If proper draft has been established, tighten the adjustment locking screw. For gas- red systems, shut o
thermostat and check for residual heat spilling from draft hood. If this occurs, a post purge timer may be
required. If so, use a Field Controls PPC-5 Electronic Post Purge or a Control Kit which includes one. Before
installing, refer to the General Installation Inspection to check for negative pressure problems in the building.
If su cient combustion air for the burner is not provided, a  ow reversal during the o cycle could occur
within the venting system. This may cause combustion problems as well as condensation that could block the
air pressure sensing tube. It may also contribute to premature motor failure. Combustion, and/or make-up air,
should be supplied from outside the structure and the air inlet should be on the same wall as the power venter
discharge. For example, tightly constructed homes and homes retro tted from electric heated systems are
more likely to experience combustion and/or make-up air problems. For further information consult “The Field
Report–E ects of insu cient combustion air on draft and heating systems”. Refer to the appropriate control
kit installation instructions for pressure switch adjustment procedure and system checkout procedures before
operating continuously.
NOTE: After proper venting has been established, it is recommended that a combustion test on gas and oil
units, a check for CO levels on gas units, and a smoke test on oil systems be performed to ensure maximum
burner e ciency. Oil burner air adjustments should be set at a zero to a trace smoke at the highest or
recommended CO
2
% setting set by heating equipment manufacturer.
GENERAL INSTALLATION INSPECTION
Recommended procedures for safety inspection of an appliance in accordance with the National Fuel Gas
Code ANSI Z223.1. The following procedure will help evaluate the venting system. It is intended as a guide
to aid in determining that the venting system is properly installed and is in a safe condition for continuous
use. This procedure should be recognized as a generalized procedure which cannot anticipate all situations.
Accordingly, in some cases, deviation from this procedure may be necessary to determine safe operation of
the equipment. If it is determined that a condition exists which could result in unsafe operation, the appliance
should be shut o and the owner advised of the unsafe condition. Corrections must be made before the
appliance is put into continuous operation. The following steps should be followed in making a safety
inspection.
1. Visually inspect the venting system for proper size and determine that there is no  ue gas spillage,
blockage, restriction, leakage, corrosion or other de ciency which could cause an unsafe operation.
2. Insofar as practical, close all building doors,  replace dampers, windows and all doors in area in which
the appliance is located. Turn on clothes dryers, any exhaust fans, such as range hoods and bathroom
exhausters so they operate at maximum speed. Do not operate a summer exhaust fan. If, after completing
Steps 3 through 7 it is believed su cient combustion air is not available, refer to the National Fuel Gas
Code ANSI Z223.1, or any applicable local codes for guidance.
3. Place in operation the appliance being inspected. Follow the lighting instructions and adjust thermostat so
appliance will operate continuously.
4. Determine that the pilot or burner is operating properly and that the main burner ignition operates
satisfactorily, by interrupting and re-establishing the electrical power of the appliance in any convenient
manner. Test the pilot or burner safety device to determine if it is operating properly by extinguishing the
pilot or disconnecting the  ame safety circuit and pressure switch sensing tube from the pressure switch.
Figure 11