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# Using vacuum gauges to tune an oil burner

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edited December 2022
Using vacuum gauges to tune an oil burner

Using vacuum gauges to tune an oil burner

• Member Posts: 1
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How do you arrive at .0086 for the fuel line diameter?
• Member Posts: 9,850
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I think the units for the tubing diameter is in feet but i still couldn't convert that to a common tubing size but the order of magnitude was right. This is why carrying units through your algebra and canceling them out is important. It also looks like it has parenthesis and variables used willy nilly which have a very specific algebraic meaning but isn't what is meant here which makes it very hard to interpret what was meant. It is a great concept but some editing by someone who understands what is meant and understands algebra would make it a lot easier to understand.
• Member Posts: 6,505
edited December 2022
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.0086 is the volume of fuel in 3/8” copper tubing, .75 is a multiplier, based on what, I have no idea (probably based on their own testing).
Also .258+3 = 3.258

L =50' length
Q=.60 gph firing rate
H=4' Vertical height

Lift Job
V = (L * .0086 * Q) + (.75 * H)
V= (50 * .0086 * .60) + (.75 * 4)
V= (.258) + (3)
V= 3.258

Gravity (tank above burner)

V = (L * .0086 * Q) - (.75 * H)
V= (50 * .0086 * .60) - (.75 * 4)
V= (.258) - (3)
V= -2.742 (no vacuum, not factored in-filters, valves, etc).

There was an error rendering this rich post.

• Member Posts: 8,157
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I was taught a long time ago that 10 ft of horizontal 3/8" tube = 1" vacuum
every foot of lift above the oil level was about 1" vacuum. So the 50 ft plus the 4 ft would be about 9" vacuum. I think that was for 2 pipe systems. I know that on a single pipe system the fuel flows much slower, so the friction loss in that 3/8" tube is much less.

Edward Young Retired

After you make that expensive repair and you still have the same problem, What will you check next?