28
McQuay IM 777-3
Service and Maintenance
Front Load Filter Option
Front loaded filter options require that the filters be removed
and replaced from inside the unit.
To remove filters, rotate the wire clips. This releases both the
prefilter and the final filter. When installing clean filters, check
to verify the filters are fully seated in the frame. See Figure 38.
Figure 38: Frame and Filters with Holding Clips
Filter Gauges
Filter gauges indicate pressure drop for installed filters.
Table 18 shows the typical filter pressure drop for clean filters
at rated air flow. The tables also show a final pressure drop for
front loaded filters.
Where a single filter gauge is used, the prefilters can be
removed to check the pressure drop of the final filters.
Figure 39: Filter Gauge
Table 17: Belt Deflection Force (per Browning
®
specifications)
Cross
section
Sheave diameter (in)
Deflection force (lbs)
Smallest
sheave
diameter range
rpm
range
Cross section A, B, 5V
Cross section AX, BX, 5VX
Used belt
New belt
Used belt
New belt
A, AX
3.0 to 3.6
1000 to 2500
3.7
5.5
4.1
6.1
2501 to 4000
2.8
4.2
3.4
5.0
3.8 to 4.8
100 to 2500
4.5
6.8
5.0
7.4
2501 to 4000
3.8
5.7
4.3
6.4
5.0 to 7.0
1000 to 2500
5.4
8.0
5.7
9.4
2501 to 4000
4.7
7.0
5.1
7.6
B, BX
3.4 to 4.2
850 to 2500
4.9
7.2
2501 to 4000
4.2
6.2
4.4 to 5.6
860 to 2500
5.3
7.9
7.1
10.5
2501 to 4000
4.5
6.7
7.1
9.1
5.8 to 8.6
860 to 2500
6.3
9.4
8.5
12.6
250 to -4000
6.0
8.9
7.3
10.9
5V, 5VX
4.4-6.7
500-1749
10.2
15.2
1750-3000
8.8
13.2
3001-4000
5.6
8.5
7.1-10.9
500-1740
12.7
18.9
14.8
22.1
1741-3000
11.2
16.7
13.7
20.1
11.8-16.0
500-1740
15.5
23.4
17.1
25.5
1741-3000
14.6
21.8
16.8
25.0
F i l t e r
F r a m e
R o t a t e
W i r e C l i p s
P r e f i l t e r
F i n a l
F i l t e r
