Free flow vs Kunkle vs Spring loaded relief valve

I am in the middle of switching my El Diablo into a newer van (2010 express 2500 extended). I have acquired a MYTEE tr80 waste tank at a great deal locally (GO FIGURE!) My El D SS tank is leaking, as did the one it replace, the achilles heal of the El D truckmount. I saw a video on another carpet cleaner forum about installing a free flow system and closing off the kunkle all together. A free flow is nothing more than a hose spigot attached to the tank lid opened up until the vac reaches 14-15 hg. Thoughts?

Aren't the free flow systems just a full-time vac leak so you don't over-pressure? Never liked that concept, or is this something else?

That kunkle valve is a good design, it is also the reason the tanks start to leak due to the higher pressures.

Location is important for the vac release, it isn't always wise to place it anywhere there is space. Is the lid strong enough that it will not flex and cause seal failure?

Another question is the vac recovery. When it releases pressure, how fast does it recover....how responsive? The kunkle on my old El D. would vent off and then VERY slowly close back off leaving me with low vac at times.

Yes, it is a concept of a small constant air leak. On my EZ, the pipe between the blower and waste tank had 3, 1/4" holes. Didn't seem to affect suction when the wand was down; It sucked!
No opinion on the knuckle.

I guess I already have free flow system then.....not by choice though.

It would make things simple, I just don't know about the value.

Let me first say, do a search about this topic on this forum, because I know this has been discussed a couple times before........I remember starting one myself.

I did it for you. lol

Not sure it has the info you want, but there is some good stuff here, where you even posted El D ..,,....

I think the only person I've ever seen push that free flow/hose bib lol, is Rob Allen........And I don't like the idea of having a constant vac leak, especially when you're not even close to max Hg.

That I think is where the Bayco and K valves have the advantage you  would want?,....or that is at least what I want that is, they don't pop off until your max Hg is hit, which is the only time you need the relief, I believe? The hose bib is leaking air all the time and decreasing vac all the time too, where the spring loaded valves aren't leaking all the time but they're starting to open and leaking way before you hit max Hg, unlike the B and K valves that just pop off at max.

I think you're biggest enemy is that poorly engineered or fabricated, maybe both? tank on the El D.
Personally, I'd stick with what you have, and ignore that kunkle-head Rob.

https://thecleanerslounge.forumotion.com/t661-bayco-kunkle-relief-valves?highlight=Kunkle

https://thecleanerslounge.forumotion.com/t1273-kunkle-valve?highlight=Kunkle

As already said this has been talked about before. I'm no engineer but it seems like we're worried about a little air leakage from a vac relief like its a big deal but if it is that big of a deal buy a bigger unit with a bigger blower. I know I don't clean carpet like you guys do, but I've talked to lots of cleaners and most never run more than 150 ft for residential occasionally 200 ft for commercial. I know air flow is key to dry times. Vacuum pressure only helps with lift right. Well I just watched a episode of Mythbusters they lifted a car with a shop vac pulling 8 in of lift with no air flow. (NO AIR FLOW ) So as for the relief valve its your preference.

^ I'm probably more concerned about a little leak here and there more than most guys because I have a small 36 blower, and do sometimes have 250-300' hose runs.

Every little bit helps, as I've discovered firsthand myself.

Well yeah I get that, a little here and there adds up to a lot. I was talking about the unit. As I said I don't do the cleaning side so I didn't think about the hose issue. That being said address the hose leaks don't try to make the blower /vac relief make up for the hose problem. Even with a perfect system with long runs like 250-300 ft you are going to have to slow down and even take a extra dry strokes. Over the years I've worked on the different types of units the biggest thing is the blower size. Size = cfm's and cfm's =lift and how fast you get the lift. Next time you are on a short run say 100 ft when you set the wand down to the carpet watch the vac hose, see how it draws up and how fast it draws up when it stops that is when the unit has a full load on the vacuum. Now do the same thing with 200 ft you will find it takes longer to get the same vac load. Long run of hose is more restrictions for air flow plus in a since makes the waste tank bigger so it takes longer to get to the 14 hg of lift. Hope I'm getting my point across with out making anyone mad at me. But look at the different in the waste tanks on units with a 33-36 blower then look at the tank on a #4 and up blower big difference you would never us a 100 gal waste tank on 33 blower. It's about how fast you can get the vac load up to the 14 hg to get max lift. Hope this makes sense.

Thank You everybody, I think I ill try the free flow method 1st. If it doesn't work out I will install the kunkle valve. If free flow is not for me I will simply tighten up the hose bib and be done with it. Check out the waste I am replacing the leaking EL D tank with. Paid $450+ tax.
http://www.mytee.com/products/t-80r-the-tank-recovery/#.Vs2yj_IrLIU

I have seen pictures of these but never worked on a unit with one. So let us know how it does when you get it installed and working.

Nice new waste tank. El D. And great price; like half price?
250-300' with a 36 blower? Holy crap batman. You must get every ounce of performance out of it!?
Ace, good explanation on vac relief.

Matt; My carpet cleaner wrote:..........................
250-300' with a 36 blower? Holy crap batman. You must get every ounce of performance out of it!?
Ace, good explanation on vac relief.

I have to, and learned how to get the max out of it over time with a lot of little improvements in the system over a few years..........lot of little things have added up to a pretty big improvement.
And the really good thing is, I have plunty of suction for quick dry times with my normal hose runs of 75-125'.

You're doing great Ace, and as always a wealth of knowledge, so Thank You!!

The spring loaded valve seems to be the best overall. The kunkle type provides great vac, but places a sudden stress on the vacuum tank, thus the metal fatigue cracks. Free flow is just that, a constant leak. The spring provides for a variable vacuum release and can be adjusted to provide both high lift and enough relief not to damage tank.