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Konus Burners, Primary, and Vat Pumps

back into the burner. In this mode, the No. 2WV valve is in the closed
position. Therefore, the oil in the burner is directed to the vat pump
suction either directly or through the primary pump, if running. This
oil is forced through the ponds heat exchanger. This heat is
dissipated to the ponds. This prevents the oil in the burners from
reaching a dangerously high temperature level.

When the temperature sensor in the ponds indicates that the
temperature is too high, the AV1 and AV2 air pilot valves energize. A
short timer (1 – 2 seconds) will then start. The valve stem will then
move up, which will restrict the flow from the heat exchanger to the
Konus burner. This restriction causes a higher pressure at the inlet of
the No. 2WV valve. More oil will flow through the orifice plate in valve
No. 2WV then back into the vat pump suction. The primary pump will
deliver the additional oil required by the vat pump. Once the timer
elapses, the AV2 valve is de-energized. Air pressure is then locked in
between the air valves and pilot chamber.

If the probe indicates that the temperature is too low, the AV1 valve
will energize and the same timer will start. The spring inside the pilot
head will then move the valve stem downward, creating a greater
flow path from the heat exchanger through the valve and to the
heaters. The pressure at the inlet port of the No. 2WV valve will then
be reduced. Less flow will be ported through the No. 2WV valve with
a lower pressure drop between the inlet and outlet ports. This means
that more oil will have to be supplied from the primary pumps to
supply what the vat pump is calling for. Once the timer elapses, the
AV1 pilot valve will de-energize, permitting the No. 3WV valve to
maintain its position. No. 3WV is a normally open, infinite positioning,
three way, air piloted, spring return, directional valve.

Troubleshooting Thermal Oil Systems Page 17