Patterson-Kelley STORM ST-2500 Installation & Owner's Manual page 33

For correct installation of a
vent system, read all of these
instructions and refer to the
vent manufacturer's
instructions.
Failure to use a proper vent
system (types and materials)
as described in this manual
will void the appliance
warranty and may result in
rapid deterioration of the
venting system, creating a
health or life safety hazard.
Faulty vent installation can
allow toxic fumes to be
released into living areas.
This may cause property
damage, injury, or death
motorized damper is fully-open, its end limit switch completes the Air Damper Interlock circuit (120VAC)
which allows the appliance to proceed to ignition.
External power supplies are required for Relay A, Relay B, Relay
C, and Relay D. Because power is provided from an external
source, the power is still present when the appliance is turned off.
Check all voltage sources have been disconnected prior to
servicing. Failure to do so could result in electrocution, injury, or
N !
OTICE
Relay A, Relay B, Relay
C, and Relay D are
rated for a maximum
voltage of 120VAC and
a maximum current
capacity of 1/2 Amp.
Customer must supply
fusing for all current
connected to the relays.
Connecting a motorized
damper which exceeds
the voltage or current
capacity of the relay
could cause permanent
damage to the relay.
Revised: June 26, 2020
Released: June 26, 2020
NOTE: The power source to drive the damper actuator motor must
be provided externally. The appliance DOES NOT provide a
power source for this purpose.
NOTE: Combustion air dampers other than those listed in the table
above may require voltages other than 120VAC. This is
acceptable, provided the required voltage does not
120VAC.
NOTE: The Air Damper Interlock circuit for the end limit switch is
always 120VAC which is sourced from the appliance itself. All end
limit switches must be rated for 120VAC.
Motorized combustion air dampers must be powered from an
external power supply other than the appliance. The figure below
shows a sample installation in which Relay C is user-selected to
operate a 120VAC motorized air damper. Relay C is normally-
open, so when the appliance is in standby, the combustion air
damper remains closed. Once a call for heat is received, Relay C
closes the 120VAC circuit (external power supply) which provides
power to the damper motor, opening the damper.
death.
© Patterson-Kelley 2020
All Rights Reserved.
P-K Storm
Technical Service 1.877.728.5351
Note: The NURO
the user to allocate Relay A, B, or
C for use with a motorized
combustion air damper. The
figure above shows Relay C in
use for the motorized combustion
air damper. Depending on the
user-configuration, Relay a, Relay
FUSED
B, or Relay C can be selected to
operate the combustion air
damper.
2691000273 P-K Storm ST2500-ST4000
Installation and Owners Manual Rev A.docx
TM
Gas Fired Boiler
exceed
Once the
®
control allows
Page 24