FPHE question. Flat Plate Heat Exchanger (FPHE) - PeachParts Mercedes-Benz Forum

bmor_62 · #1 01-01-2013, 12:51 PM

Can I run a FPHE year round or does it have to be plumbed in with valves to disengage during the hotter months?

bmor_62 · #2 01-01-2013, 05:00 PM

This application is for the aforementioned 83 300SD, running a WVO/Diesel blend of 60% to 80% WVO depending upon the ambient temperature, single tank, no heat added yet.

grease lightnig · #3 01-01-2013, 09:48 PM

You can run it all year long, it does not heat that much it only gets as hot as the coolant.

Jack None · #4 01-04-2013, 02:30 PM

I see two possible concerns.

First, is the fuel lubricating the IP enough? This wouldn't be a problem with veg, but might be a problem with #2.

Second, is the veg in the tank getting hot? If so you increase the rate of oxidative polymerization. If you're looping the veg return this obviously won't be a problem. I'm currently sending the veg back to the tank, and on a hot day the tank can get very warm. I've been getting less than 2k out of my veg filters. My problem is either a) insufficient prefiltering (I filter to 1 micron but I tend to wash out the poly bag filter and reuse it, which I'm going to stop doing); b) beasties growing in the oil; or c) little bits of polymerized veg "fruit leather" from the warm tank detaching and ending up in the filter.

Jack None · #5 01-04-2013, 02:33 PM

In other words, if you're still in the planning stages, get three valves and loop the veg return! (with an option for sending back to tank for purging) If I ever get around to upgrading my system this is on my list.

jltcasper3 · #6 01-06-2013, 09:23 PM

i run fphe year round, no problems. Yes loop your return it is worth the extra cost in saved filters. I do have a shut off valve for all coolent flow to veg system so i could fill up with diesel if i don't have any vo

bmor_62 · #7 01-07-2013, 08:55 PM

Are there still advantages to a looped return on a single tank blending scenario?

jltcasper3 · #8 01-07-2013, 09:35 PM

i would say yeah because, the hot unused fuel won't be returning all the way to tank and then bring in colder fuel again, it will just keep circulating the hot and filtered fuel, and also longer filter life. This is all pending how u plumb it and how it's heated too.

Fattyman · #9 01-27-2013, 08:32 PM

Use a 3 way valve at the return T of a looped system. That way you can switch to a normal return when you change filters to purge the air.
Then switch it back to loop when finished.
Have fun.

Phillytwotank · #10 01-27-2013, 08:55 PM

I would suggest pluming a ball valve in the hot water supply line for the system.

Unnecessary heating of your fuel can lead to unwanted effects.

Inexpensive and easy element of control that can be added to your system.

bmor_62 · #11 02-24-2013, 05:11 PM

I got my FPHE. I am going to pick up some hose barbs; All the ports on the FPHE are 1/2" NPT females, so I need to get 1/2" male to 5/16 for fuel and 1/2" to 1/2 for coolant, correct?
Oh and I need to get a tee for the coolant and a ball valve as well.
Just thinking out loud here fellas, trying to get all I need in one trip.

Simpler=Better · #12 02-26-2013, 09:06 AM

You should be able to find all the brass from Ace or a local plumbing store. Those sizes sound correct

moon161 · #13 02-26-2013, 01:04 PM

Quote:

Originally Posted by bmor_62

trying to get all I need in one trip.

Hope springs eternal

Fattyman · #14 02-27-2013, 08:14 PM

Quote:

Originally Posted by bmor_62

I got my FPHE. I am going to pick up some hose barbs; All the ports on the FPHE are 1/2" NPT females, so I need to get 1/2" male to 5/16 for fuel and 1/2" to 1/2 for coolant, correct?
Oh and I need to get a tee for the coolant and a ball valve as well.
Just thinking out loud here fellas, trying to get all I need in one trip.

1/2 5/16 for the fuel lines is correct. I like the 90 degree ones. But those are hard to find. You'll probably end up with a 1/2 to 3/8 reducer and then a 3/8 to 5/16 fitting.
For the hot water you'll need 1/2 to either 5/8 for the lower heater line at the boost pump and 1/2 to 3/4 for the upper heater line coming out of the head.
Get a cross flow going so the 2 fluids are traveling in opposite directions. You'll get better heat transfer.

bmor_62 · #15 02-28-2013, 06:11 PM

This raises the question, where do you suggest is the best place to tap in and return the hot coolant? I'd guess at the head you'll get the hottest coolant.

Quote:

Originally Posted by Fattyman

1/2 5/16 for the fuel lines is correct. I like the 90 degree ones. But those are hard to find. You'll probably end up with a 1/2 to 3/8 reducer and then a 3/8 to 5/16 fitting.
For the hot water you'll need 1/2 to either 5/8 for the lower heater line at the boost pump and 1/2 to 3/4 for the upper heater line coming out of the head.
Get a cross flow going so the 2 fluids are traveling in opposite directions. You'll get better heat transfer.