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Table 26. K-factor for relief fans
Fan Model
K3G500
K3G560
Use this equation to determine flow for relief fans:
Where K is determined based on the fan model number, ρ
is standard air density of 0.075 lb/ft
density, and ΔP is the pressure differential measured by
the pressure transducer. The equation gives flow for one
fan. Airflow must be multiplied by the number of fans
installed in the unit.
Traq™ Sensor Airflow Measurement
(Optional with all units equipped with an economizer)
1. Use to program the following system components for
Economizer operation by scrolling through the displays;
•
Supply Fan (On)
•
Outside air dampers (Selected % Open)
•
Variable Frequency Drive (100% Output, if
applicable)
•
Outside Air CFM Setpoint
•
Outside Air Pre-Heater Operation (if applicable)
2. Navigate to Supply Fan Manual Overrides. The supply
fan speed will be adjusted through the user interface.
With the unit in Stop, touch the Manual Override button
for the Supply Fan. Set the Fan Speed to 100%.
3. With the unit operating in the "Manual Override", the
amount of outside air flowing through the Traq™ sensor
can be viewed.
4. Navigate to the "ECONOMIZER POSITION" and read
the corresponding damper opening percentage (%).
Gas Furnace Startup
Staged, Modulating, and Ultra
Modulating
It is important to establish and maintain the appropriate air/
fuel mixture to assure that the gas furnace operates safely
and efficiently.
The volume of air supplied by the combustion blower
determines the amount of oxygen available for combustion,
while the manifold gas pressure establishes fuel input. By
measuring the percentage of carbon dioxide produced as a
by-product of combustion, the operator can estimate the
amount of oxygen used and modify the air volume or the
gas pressure to obtain the proper air/fuel ratio.
Confirming the correct air/fuel mixture for a furnace results
in rated burner output, limited production of carbon
monoxide, and a steady flame that minimizes nuisance
shutdowns.
RT-SVX063G-EN
K-factor
281
348
s
3
, ρ
is ambient air
a
High-Fire Adjustment
WARNING
Hazardous Gases and Flammable
Vapors!
Failure to observe the following instructions could
result in exposure to hazardous gases, fuel
substances, or substances from incomplete
combustion, which could result in death or serious
injury. The state of California has determined that
these substances may cause cancer, birth defects, or
other reproductive harm.
Improper installation, adjustment, alteration, service
or use of this product could cause flammable
mixtures or lead to excessive carbon monoxide. To
avoid hazardous gases and flammable vapors follow
proper installation and setup of this product and all
warnings as provided in this manual.
WARNING
Explosion Hazard!
Failure to properly regulate pressure could result in a
violent explosion, which could result in death, serious
injury, or equipment or property-only-damage.
When using dry nitrogen cylinders for pressurizing
units for leak testing, always provide a pressure
regulator on the cylinder to prevent excessively high
unit pressures. Never pressurize unit above the
maximum recommended unit test pressure as
specified in applicable unit literature.
1. Program the following system components for
operation by scrolling through the User Interface
displays:
Gas Heat
a. Open the manual gas valve, located in the gas heat
section.
b. Navigate to the Gas Heat Manual override screen
and set the modulating percentage to 100% or
enable the 1st stage. Touch the Auto button.
c. Turn the Supply Fan on by navigating to the Manual
Override Screen. Set the Fan speed to 100%.
2. Once the system has started, check the appearance of
each burner's flame. Color should be blue for natural
gas with a small amount of visible orange.
3. Check the manifold gas pressure of each gas valve by
using the pressure port on the manifold section
downstream of the valve. The manifold pressure for
each valve at High Fire should be set to 3.5" w.c. (10.0"
w.c. for propane).
Note: On modulating gas units the one-stage valve just
upstream of the modulating valve setting will be
approximately 4.5"w.c. to achieve a manifold
pressure of 3.5" downstream of the modulating
valve on high fire.
Startup the Unit
59
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