Tee in a diesel return line??

[FatDaddyG]

Are tees in the return line ok? I’ve got a 6K generator and the ol’ Perkins sharing 2 tanks. There is a simple tee the the feed line from the Raycor but they ran the genset return straight to the aux tank. Is there a reason for that or did the installer just run out of tees?

[Cheechako]

Hard to say why, but for a return line, the main issue is making sure it wont overfill a tank over time. Other than that , doesn't matter which tank it goes to. Return fuel flow is pretty minimal usually.
On a boat I had with two tanks I just had the return line and feed line each on a 3 way valve. I always turned them to the same tank and returned the fuel to whichever tank it came from.

[Bill O]

Originally Posted by Cheechako

On a boat I had with two tanks I just had the return line and feed line each on a 3 way valve. I always turned them to the same tank and returned the fuel to whichever tank it came from.

We have 2 tanks and a 3 way valve to divert the return to either tank. Similarly, we generally return the fuel to the tank we are using, but can be switched over to the other tank to help balance the fuel amount if that tank is low.

[rdempsey]

I used a tee in the return line for my fuel polishing setup.
7 years later and no problems.

[sv_pelagia]

We have a tee (actually, a 2-way valve) on our return line so that we can switch to fill up our diesel heater(s) header tank. We watch carefully so we don't overfill. Works great.

[capt jgw]

The fuel return can be tee'd into the fuel supply line upstream of the lift pump. A lot of engines are plumbed that way, saves a lot of pipe or hose. A lot easier if you have multiple tanks with a feed selector, you don't have to do anything with the return. Only downside I know of is it takes a little longer to bleed air out, any air in the return will go through the system again. My boat has twin Perkins mains and an Onan genset, all are plumbed this way.
I'm not sure this would work with a common rail engine, they return a lot of fuel. In mechanical diesels it's just a dribble.

[Engine man]

Originally Posted by FatDaddyG

Are tees in the return line ok? I’ve got a 6K generator and the ol’ Perkins sharing 2 tanks. There is a simple tee the the feed line from the Raycor but they ran the genset return straight to the aux tank. Is there a reason for that or did the installer just run out of tees?

You MAY be introducing air into your fuel system when installing a Tee, this is why every engine should have it's own return fuel hose. Joe