Greg, my oil comes from just a couple of privately owned restaurants, who'd otherwise be paying to have it disposed of at the Commune's
décheterie. It's mainly fried "fish & chips" oil, with occasional fried chicken, breadcrumbs 'n herbs debris from a pizza joint. No supply problem as yet- just the opposite - I have over a year's supply in stock now but daren't lose my good suppliers...
Larry, the diesel tank's head has no effect on flow rate, which is controlled soley by the gear-pump pressure and the nozzle's GPH rating. The GPH is constant, regulated by a relief valve in the gear-pump, which bypasses surplus fuel back to [in this case] the gear pump inlet. [I have a 'one-pipe' diesel supply, which I omitted to mention in my efforts to keep the blurb to a minimum - see last pic but one, with the existing redundant return line plugged with a spare fire-valve]. The peristaltic pump has a constant flow rate once set, of about 1 liter per hour. It is only a 3.5 watt motor but [tip] it flipping hurts if you stick your finger in the rotor like wot I did!
Gear-pump failure scenario. Good point, thanks and a new note added to the instructions!
No fuel then flows to the burner, which would 'flame out'. The Protek valve shuts at 135 psi, so there is a
minimum oil pressure. The trachoidal gear set is virtually oiltight unless rotating, so VO
would then be pumped toward the diesel tank. But a 'flame out' will be seen by the photo-resistance flame monitor, which will lock-out the LOA Controller, shut down the burner and wait for a manual reset. A lock out also shuts off the peristaltic pump and its solenoid valve. This usually takes a few seconds, but in this case, worst scenario, the photo-cell might 'see' the combustion chamber for half a minute or so while it cools down. Half a minute is only 8cc of VO, [ 2 teaspoons ], but it's enough to warrant a manual flush-out, which would be my normal reaction to a power outage. Flushing out is easy. I have a spare 3-pin Danfoss LE pump plug and can spin up the gearpump independantly to run diesel out of the finger tightened air-bleed nipple at the 'Y' manifold which is just visible under the pressure gauge, [a necessary chore with 'one-pipes', which don't auto-bleed.]
A non-return valve in the diesel line would risk damaging the peristaltic pump gearing &/or its motor windings - or a blown-off VO pipe- [it's only push fit tube] if it has 'nowhere to go', so that option is out.
