Belt Tension Adjustment - Central System; Belt Tension Adjustment - Small Hvac System H-Series; Belt Tension - Small Hvac System X-Series - PREVOST H3-41 Maintenance Manual

SECTION 22: HEATING AND AIR CONDITIONING
3.6.2 Belt Tension Adjustment – Central
System
On the mechanical tensioner (Figure 26), slightly
slack lock bolt (A). Adjust tension by turning
adjustment screw (B). Tighten the lock bolt (A)
to preserve adjustment.
TORQUE: 43 lb-ft (58 Nm)
Should the idler bearing need to be serviced,
tighten shoulder bolt (C) at reassembly.
TORQUE: 31.5-38.5 lb-ft (43-52 Nm)
(M12 shoulder bolt)
TORQUE: 59 lb-ft (80 Nm)
(M12 x 1.75 std bolt)
FIGURE 26: TENSIONER ON CENTRAL A/C
For H3 series vehicles equipped with a 3
alternator, (Figure 25) belt tensioning is also
applied through air bellows which is adjusted by
an air pressure regulating valve pressure (Figure
27). The correct pressure of 45 psi is set at the
factory. Periodically verify the pressure at the
regulating valve using a pressure gauge and
correct if required.
24 PA1621 Maintenance Manual All Series | Revised February 2019
FIGURE 27: BELT TENSIONER CONTROL VALVE - H3
SERIES
3.6.3 Belt Tension Adjustment – Small Hvac
System H-Series
Belt tensioning is applied through air bellows
which are adjusted by an air pressure regulating
valve (Figure 27). The correct pressure of 45
psi.is set at the factory. Periodically verify the
pressure at the regulating valve using a
pressure gauge and correct if necessary.
22381
rd
FIGURE 28: BELT LAYOUT WITH SMALL A/C
COMPRESSOR H-SERIES
3.6.4 Belt Tension - Small Hvac System
X-Series
Belt tension is achieved by an automatic belt
tensioner. No adjustment is required.
12219