Fuel Pressure loss on Loop upline

[I-TERA]

I tried to figure out how to verify the temperature-vapor lock hypothesis.
One simple way to exclude exhaust impact is to cover from outside the small area of the filter with thin aluminum foil taped to the belly.
I never had problems switching tanks ( every 20 minutes). I always fly with aux pump off.
If vapour bubbles are generated in the filter , running the aux pump with a clear outlet tube to a canister the bubbles will be visible and also bubbles if air is coming in upstream the pump.
I discovered at my expenses that it is necessary to change compressed o-rings if dismantled and reinstalled.
Claudio

[SMO]

Originally Posted by I-TERA

I do not have your automatic low pressure control ( may I know how it function? )

I have the Vertical Power VP-200 electrical unit, and this is one of the many features. The VP-200 was discontinued a number of years ago.

[I-TERA]

Thank you, I think it's a very useful feature.
After the pump trips do you have to switch it off? or the pump runs for a wile and go off automatically if the pressure remain stable?
Claudio

[SMO]

I have to switch it off manually, it will not go off by itself. I also really like the feature, along with many others in this unit. See this post:
http://www.vansairforce.com/communit...9&postcount=20

[I-TERA]

Tanks Mark,
very rich device. Your successfull application of the FP function suggest me to develop a small circuit only for the automatic aux fuel pump function, may be with a delayed auto off and cyclic pressure test. The alarms are actually managed by the efis.
Claudio