Boost pump on, all the time?

Pilottonny · #1 09-23-2007, 03:46 AM

Hello guys,

I am currently installing the boost pump (Vans kit) for my fuel injected engine. In the manual it says that the pump is made for continues operation. I searched the forums but everybody seems to switch the boost pump on and off, for take-off, landing, changing tanks, etc. I could not find a reason why the pump can?t be on all the time though.
I was thinking of wiring it to the ?on?-position of my ignition switch to have it running all the time when the engine is running.

For instrument set-up, programming the GPS, etc., I would have an ?accessories? position on the ignition switch, like in a car, at which position the pump would not be running. Switching the pump off in an emergency (fire) can be done with the circuit breaker.

Comments, anybody?

Regards, PilotTonny

Captain_John · #2 09-23-2007, 03:55 AM

Tonny,

In the electrical industry, continuous duty is defined as operation for 3 hours or more.

The pump is designed to take that kind of usage. That isn't meant to say that that is how you are actually supposed to use it.

Shut it off when you reach cruising altitude.

Hope this helps!

CJ

AltonD · #3 09-23-2007, 04:12 AM

Look at your procedure for normal and hot starts of a fuel injected engine. you need to be able to turn it off.

RV8N · #4 09-23-2007, 05:41 AM

If it is always on, you will have no indication that the engine driven pump has failed.

I would turn it off when you get to a safe altitude and use it only for take-offs and landings. The electric pump is meant as a back-up not as a primary pump.

Karl

Mel · #5 09-23-2007, 06:47 AM

Quote:

Originally Posted by Pilottonny

Hello guys,

I could not find a reason why the pump can?t be on all the time though.

Extra current draw, Extra wear on the pump, "masking" of a failed mechanical pump.
Wire it with it's own switch!

Harold Lanfear · #6 09-27-2007, 02:23 AM

I fly a Certified aircraft with a "always-on" electric fuel pump, except for starting, checking the mechanical pump during run-up, etc. Guess what fails? - that's it; the $1400+ electric fuel pump. Save your pump for backup when you need it on T/O and landing.

By the way, I've never lost a mechanical pump - bless them!

Harold

steve_adams · #7 09-28-2007, 02:04 PM

I know the rotax is a lot different, but... In reading the Kitplanes article about the RV12, Vans has designed the plane to have the electric pump always on for simplicity. Just food for thought.