![background image](http://html1.mh-extra.com/html/gardner-denver/vst225/vst225_installation-operating-and-service-manual_3899650049.webp)
13-17-609 Page 48
5-3
OIL SIGHT GLASS
- This device indicates oil level within the air/oil reservoir
– See Figure 5-1 for details.
Figure 5-1 – OIL LEVEL SIGHT GLASS
To ensure best performance from the oil separation system, adhere to the following guidelines:
·
Before starting the unit, make sure that oil level is visible in the sight gauge. An oil level of at
least ½ the sight gauge height will ensure there is enough oil to safely operate the compressor.
·
During unit operation, and after a steady compressor discharge temperature is reached, check
the oil level:
o
Add oil only when the level is below the LOW mark on sight glass. This will make the refill
intervals less frequent. Note that each inch of oil level represents 2.0 gal. of oil.
o
Drain oil only when the level is above the HIGH mark on sight glass. Be aware that a
stopped unit, when filled to its maximum oil capacity (approximately 32 gallons), may show
a full sight glass
– this is normal and does not require oil drainage.
o
The oil level in the sight glass will fluctuate as the compressor load changes, as a function
of the air/oil volume ratio within the compressor pipe works. Refer to Figure 5-1 for typical
operational oil levels attained at various compressor load levels and with a full charge of oil:
Controller Display
Load Level - %
Oil Sight Glass
level with full oil
charge - inches
Oil Sight Glass
lowest acceptable
level - in
100
4.0
2.0
80
3.5
1.5
60
3.0
1.0
40
2.5
.5
20
2.0
.0
Figure 5-2 – LOAD vs SIGHT GLASS OIL LEVEL CHANGE