DA20-C1 Electric fuel pump

[Steven]

I posted this on the other forum, and I was hoping to get some opinions from those here as well.

I just picked up my DA20-C1 from Phoenix. Nice plane, I really like it. But, I noticed something unfamiliar. When I turn on the electric fuel pump I cannot hear it at all. I am wondering whether or not it is functional.

In other Diamonds I have flown (DA20-A1, DA40, other DA20-C1's) I have always heard the electric fuel pump operate. What is other people's experience?

My understanding is that the fuel pressure generated by the low side is too low to read reliably on the fuel pressure gauge. So how would you ever know whether or not it is working, except by sound?

Note that I am not referring to the high pressure prime pump, I can hear that one loud and clear.

[Gary]

I just picked up my DA20-C1 from Phoenix. Nice plane, I really like it. But, I noticed something unfamiliar. When I turn on the electric fuel pump I cannot hear it at all. I am wondering whether or not it is functional.
In other Diamonds I have flown (DA20-A1, DA40, other DA20-C1's) I have always heard the electric fuel pump operate. What is other people's experience?
My understanding is that the fuel pressure generated by the low side is too low to read reliably on the fuel pressure gauge. So how would you ever know whether or not it is working, except by sound?
Note that I am not referring to the high pressure prime pump, I can hear that one loud and clear.

I am not familiar with the DA20 fuel system but am curious about having a separate electric prime pump and boost pump. In the DA40 there appears to be only one electric fuel pump in addition to the engine driven fuel pump. It is used for priming before to engine start and prior to landing, switching tanks, and high altitude operation whatever that means. There is only one switch for the supplemental electric pump in the DA40. Does the DA20 have an electric pump that runs continuously in addition to an engine driven fuel pump and electric prime fuel pump?
Gary

[Steven]

Gary,

In the DA20 there is one physical Dukes pump, but it has a high side and a low side. The high pressure side (or Prime Pump) is used only for priming before and during engine start. The low pressure side (or Fuel Pump) is used during engine start, takeoff, landing, and low throttle situations (e.g., slow flight). There are two separate switches.

In addition there is the usual engine driven fuel pump for which there is no switch, of course.

I don't know why the DA20-A1 had one switch, the DA20-C1 has two switches, and the DA40 has one switch. Different requirements for different engines I suppose.

[Gary]

Steven,
Thanks for the explanation.
Gary

[gsontheimer]

Have not flown the DA20-C1 for a while. As far as I remember, I could only hear the fuel pump when the boost switch was on. This is why I forgot to switch the fuel pump off after takeoff quite often. And the fuel pressure is very low when idle, even with the electrical pump on. Seems what you describe.

Gerhard

[Steven]

Have not flown the DA20-C1 for a while. As far as I remember, I could only hear the fuel pump when the boost switch was on. This is why I forgot to switch the fuel pump off after takeoff quite often. And the fuel pressure is very low when idle, even with the electrical pump on. Seems what you describe.

Gerhard

You are right, you certainly cannot hear the fuel pump when the engine is running. I guess there is no way to tell if it is working without pulling it out.

[gsontheimer]

Steven, I am pretty sure, that you could not start the engine without the electrical boost pump. So if you can start the engine, the pump is working, I would assume.

)

Gerhard

[Steven]

Steven, I am pretty sure, that you could not start the engine without the electrical boost pump. So if you can start the engine, the pump is working, I would assume.

)

Gerhard

Gerhard,

I'm not sure. I believe the Prime Pump (high) side and the Fuel Pump (low) side operate independently. The Prime Pump side is clearly working, since as you mention, I can start the engine.

[Steven]

Just to add some info to this discussion, a mechanic pulled out the fuel pump and it was definitely not working. He installed a remanufactured one, and I can hear that one when it is operating, just like I remember. So to be clear, there is definitely an audible sound from the low pressure fuel pump in the DA20-C1, and if you can't hear it you should investigate further.

As an aside, I'm quite dissapointed that the previous owner was either unaware of the problem or chose not to disclose it. In addition to the bad fuel pump, it turns out that the replacement trim switch he had installed 2 years ago is wired backwards (so the trim moves the wrong direction when you push the button). And the Heading Indicator is also bad. $3,000 in repairs before the plane even got home. I guess the previous owner really did find a bigger sucker.

It is a great plane though, and I'm sure I will enjoy it for a long time now that it is fixed up.

[Gary]

As an aside, I'm quite dissapointed that the previous owner was either unaware of the problem or chose not to disclose it. In addition to the bad fuel pump, it turns out that the replacement trim switch he had installed 2 years ago is wired backwards (so the trim moves the wrong direction when you push the button). And the Heading Indicator is also bad. $3,000 in repairs before the plane even got home. I guess the previous owner really did find a bigger sucker.

It is a great plane though, and I'm sure I will enjoy it for a long time now that it is fixed up.

I had similar problems with the 2003 DA40 I purchased in August 2007. The Nav radio of the Garmin 430 went bad the day after I took possession. I think it cost around 700 to have it fixed. The same day the I discovered that the passenger headset squealed and it turned out to be a short in the audio panel which cost a couple of hundred dollars to diagnose and repair. The HSI went bad a couple of months after I got it and the repairs cost around $2,500. The rubber donuts were bad. This is all after the pre-purchase inspection and annual at a Diamond service center. The good news is that after the rocky start I have really enjoyed owning this plane for the past 3 years.
Gary