Krueger | 1401 N Plano Rd | Richardson, TX 75081 | 972.680.9136 | kruegerinfo@krueger-hvac.com | www.krueger-hvac.com
KAH Operation & Maintenance Guide
Page: 34 of 88
SECTION 2 - START-UP & OPERATION (CONTINUED)
FIGURE 32 - PRESSURE PROBE DIRECTION
BLOWER
HEATER
AIR FLOW
BLOWER
HEATER
AIR FLOW
PICK UP TUBE TOWARDS BLOWER ATTACHED
TO HIGH PORT OF AIR FLOW SWITCH
PICK UP TUBE TOWARDS BLOWER ATTACHED
TO LOW PORT OF AIR FLOW SWITCH
TOP VIEW OF UNIT
POSITIVE PRESSURE / AIR BLOWN THROUGH HEATER
NEGATIVE PRESSURE / AIR BLOWN THROUGH HEATER
BLOWER
HEATER
AIR FLOW
BLOWER
HEATER
AIR FLOW
PICK UP TUBE TOWARDS BLOWER ATTACHED
TO HIGH PORT OF AIR FLOW SWITCH
PICK UP TUBE TOWARDS BLOWER ATTACHED
TO LOW PORT OF AIR FLOW SWITCH
TOP VIEW OF UNIT
POSITIVE PRESSURE / AIR BLOWN THROUGH HEATER
NEGATIVE PRESSURE / AIR BLOWN THROUGH HEATER
FIGURE 31 - AIRFLOW SWITCH CONNECTIONS
C
NO
NC
LOW PORT
HIGH PORT
MOUNTING
BRACKET
OPERATION
WARNING -
DO NOT penetrate wireways in any
manner. These sheet metal channels, which run
along the top panel, contain electrical wires and
connections. Electrical shock and/or damage to
the AHU may result.
WARNING -
Rotating parts and electrical shock
hazards exist. Follow the latest lockout/tag out
procedures to lockout/tagout the fan motor(s) and
heat power disconnects before servicing. Failure
to follow proper safety precautions may result in
serious injury or death. Refer to general safety
guidelines and safety symbols located at the front
of this manual.
WARNING -
Always replace RED metal tab on
access doors that provide access to moving parts.
This mechanical protection from moving parts is
required by UL-1995.
Always replace RED metal tab on access doors
that provide access to pressurized areas. This
mechanical protection is to prevent accidental
release of access doors under positive pressure.
WARNING -
Do not weld or use torches on the
exterior or interior of the AHU housing. The housing
contains polyurethane insulation, which, when
under combustion, will produce harmful, toxic
gases resulting in personal injury or death.
Verify conformance with the total outdoor airflow and
space supply airflow requirements of ASHRAE Standard
111, SMACNA’s HVAC Systems - Testing, Adjusting and
Balancing, 2nd edition, or equivalent.
NOTE -
Never use silicone caulk/sealant or caulk/
sealant containing silicone in or on air handling
equipment.
Test and Balance
Air Balance
•
System air balance should be performed as soon as
possible after AHU start-up.
•
Failure to perform air balance may result in damage
to AHU, generate noise vibration and condensation
carryover.
•
Qualified air balance technician should perform air
balance.
Dynamic Balance
•
Dynamic balance has been performed at the factory
on the fan assemblies. If any changes were made
to the fan assembly (fan, motor, sheaves, belts,
isolators, support structure) a vibration analysis must
be performed and the fan assembly trim balanced if
needed.
•
Dynamic balance is affected by operation of the VFD.
If a VFD is provided, refer to the caution warnings in
the VFD start-up instructions in the VFD operator’s
manual. Make sure the skip frequencies (jump
frequencies) are installed prior to operation of the
motors for more than 30 minutes.
