Figure 5-3 - Combination Oil Filter And Thermostatic Mixing Valve - Gardner Denver VST110 Operating And Service Manual

6. Press the oil filter assembly into the housing, and using the 1" socket, tighten down until the o-rings
seat within the housing. Do not over tighten.
7. After the compressor is started and pressurized, inspect housing-to-element joint for leaks.
OIL MIXING VALVE – This device, located at the inlet side of the oil cooler, mixes cooled and hot oil prior
to delivery to the oil filter and oil injection manifold. It helps to maintain a minimum oil temperature of
approximately 140°F at low load level or low ambient temperature conditions. The oil mixing valve shares
a common housing with the oil filter – see Figure 5-1 for details.
Figure 5-3 – COMBINATION OIL FILTER AND THERMOSTATIC MIXING VALVE
The thermostatic element of this device expands with heat. When the hot oil coming from the separator
reservoir is below 140°F, the valve bypasses oil flow around the oil cooler. Within the range of nearly 8°F
above 140°F, the valve gradually mixes the hot oil with cool oil coming from the oil cooler. Above this
range, the valve reaches its maximum expansion and all the oil is sent to the oil cooler.
OIL FLOW CONTROL VALVES - These devices feed a regulated amount of oil into various areas of the
1st stage compressor and inter-stage manifold. Each of three (3) normally open solenoid valves is paired
with one or more in-line orifices to deliver distinct oil flows. When used in combination with a permanently
open injection line, the system provides five (5) distinct oil flow regimes - a summary of the logical steps
controlling the opening and closing of these valves is shown on the footnotes of Figure 4-3, page 33.
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308VST810-A
(Ref. Drawing)