Krueger | 1401 N Plano Rd | Richardson, TX 75081 | 972.680.9136 | [email protected] | www.krueger-hvac.com
KAH Operation & Maintenance Guide
Page: 60 of 88
SECTION 4 - SERVICE & REPAIR
SERVICE INFORMATION
All necessary tags and decals to aid in service or to indicate
caution areas are provided. Electrical wiring diagrams are
attached to the control panel access door. Installation,
operation, and maintenance manuals are supplied with
each AHU.
This AHU offers unlimited unit access with completely
removable panels. All of the AHU panels, including the top
panels, can be completely removed. Removing the top
panels allows the use of overhead cranes and gantries
to remove and service the components. Fan and filter
segments come equipped with doors.
TROUBLESHOOTING
An HVAC air system includes the AHU and the entire air
circuitry through which airflows. Included are the following
parts/assemblies:
•
Ductwork, Fittings, and Branch Ducts
•
Dampers
•
Heat Exchangers
•
Air Filters and Sound Traps
•
Coils
•
Elbows and Diffusers
•
Grilles, VAVs, and MITs
•
Other items through which airflows or which offer
obstruction to airflow.
While differences in temperature and humidity may cause
air movement, it may be considered very slight compared
to the positive circulation required in an air conditioning
system. To accomplish this air movement, a fan performs
two functions:
•
Produce sufficient pressure or head to accelerate the
mass of air from a state of rest to the required velocity.
•
Produce sufficient pressure to overcome any
resistances to the flow of air.
Determining these pressures is important when
troubleshooting an air conditioning system. The generally
accepted standard instrument for measuring these unit
pressures is the pitot tube as shown in Figures 69 and 70
(right). The pitot tube is used in conjunction with an inclined
manometer, magnehelic gauge, or a tube manometer.
When the pitot tube is used in conjunction with these
instruments, one is able to read velocity pressure (VP),
static pressure (SP), and total pressure (TP) within the
system.
FIGURE 69 - CONSTRUCTION OF PITOT TUBE
8 in. x D
SOLDER
D
0.02 in. DIAMETER HOLES
DRILLED THROUGH
OUTSIDE TUBE
STATIC TUBE
IMPACT
TUBE
8 in. x D
FIGURE 70 - PITOT TUBE
