When checking the vacuum on an oil burner pump, have you ever thought about exactly what are you looking for. Are you looking for a high vacuum (indication of a plugged oil line) or very little vacuum (possible air leak or bad pump)? To actually check for these

problems, you must know the calculated operating vacuum.

To calculate what the normal operating vacuum should be, use the following procedure:

When using the standard 3/8” or 1/2” O.D. copper tubing, the following
calculated vacuums will apply:
1. Every 10 FT. of horizontal run equals 1” vacuum
2. Every one vertical ft. equals 1”vacuum.
3. Each fire-0-matic or fusible valve equals 1” vacuum
4. Clean filter equals 1” vacuum.
5. OSV valves equal 3”vacuum.

Referring to the above information and the example of a typical installation below, we can determine what the total calculated vacuum should be for the example.