Vac-Sys SE1 with Excel pump not holding vacuum

[kurtww]

I have been putting a system together like many others. I ordered two SE1 units a while back, and an Excel pump kit from Veneer Supplies. Rather than just the bare pump, I ordered the whole kit which includes a vacuum storage tank. That went together really well, and I was able to connect the Festool hose to it with the quick connect fitting, and everything works great up to the valve. However, once I connect a single vac head to it, the vacuum drops to around 2 (from 22) and the pump runs constantly. This is not enough pressure to hold things securely at all. I can easily pop a piece of baltic birch off the vacuum head. It seems like there is a leak somewhere, but I'm not sure where it could be. If I close off the shut off valve seen in the video, it holds pressure indefinitely. But as soon as I connect either the main vac pad, or the other hose that holds the base to the bench, the vacuum is almost gone. This is without a splitter or release pedal or anything else, just the single quick connect fitting connected directly to the pump.

Here are two videos, not sure if this is the best way to post them:
https://drive.google.com/file/d/1VTSN9jclG9WhK_GYoudKxDxk0mE84ADV/view?usp=sharinghttps://drive.google.com/file/d/1DC2uslTHJaWESyNY-OXVg4Dr01claUB2/view?usp=sharing

Anyone have a clue what could be going on? I don't think it's the SE1 unit as I have two and they both do the same thing.

 

[kurtww]

Just to follow up on my own post. I took the pump kit apart and ran the pump directly into the Vac Sys head, and it works fine. It seems to be a problem with the rest of the assembly. Very strange as it holds a vacuum perfectly if I close off the valve, but as soon as I open it up the pressure drops to the point where I can pull boards off the head easily. Without the extra reservoir, it holds the board as expected. I thought a vacuum reservoir was helpful?

[huh]

 

[afish]

Posted before but vacuum will find the smallest of leaks and since there isnt a large reserve even a small leak can make a big difference. I have a lot of feet of pvc ran for vacuum and had a leak I could not find.  I ended up plugging my compressor (with PSI) tuned way down and used soapy water to find any of the leaks.  As soon as I pressurized the system I could hear one of them.  My guess is one of the caps on the reservoir tanks has a leak.  If you are leaking that much it sounds like you might have multiple. 

 

[Cheese]

I thought a vacuum reservoir was helpful?
[huh]

A reservoir is a very good thing for that power failure emergency, it gives you extra time to unload the Vac Sys before it dumps your project on the floor.

The good news is you now know what you have to look at. I’d start with the QD connectors and then look at every other connection. It’s a slow painful process.  [smile]

Another area to look at is do you have the slide valve on the SE 1 enabled to use the base as a reservoir? If so are you getting a good seal between the base and whatever it’s sitting on. If it’s sitting on MDF that’s a very porous material.

 

[afish]

As cheese pointed out the QD connectors do tend to leak with vacuum (not sure about the festool ones) The one joe sells on his site has worked well for me but Miltons and the china ones from HD I have had bad luck with.

If you're draining your reserve tank almost instantly then you have a significant leak/leaks.  The fact you say when you go straight from the pump to the vac sys and everything is good tells me the leak is in the section you built.  If it was MDF or vac sys to bench seal issue bypassing the DIY section you added would have produced the same result assuming nothing else changed.  If you find that you have a leak on a PVC fitting then you can apply more pvc glue while the system is under vaccum.  I doubt you will draw glue into the pump but use a section of clear tube before the pump and use a PVC glue like the Crissys red hot which is bright blue.  That way you can easily see it in the tubing.  I had a few fittings that leaked instead of cutting them apart and redoing them I just applied glue to the joint under vacuum and have had zero issues with leaks since.   

 

[Cheese]

As cheese pointed out the QD connectors do tend to leak with vacuum (not sure about the festool ones) The one joe sells on his site has worked well for me but Miltons and the china ones from HD I have had bad luck with.

If you're draining your reserve tank almost instantly then you have a significant leak/leaks.  The fact you say when you go straight from the pump to the vac sys and everything is good tells me the leak is in the section you built.  If it was MDF or vac sys to bench seal issue bypassing the DIY section you added would have produced the same result assuming nothing else changed. 

The Festool branded QD connectors (made by Prevost) do not leak.  [smile]

This is from Beswick Engineering, manufacturers of QD couplings for both pressure & vacuum applications.

"Quick Disconnect use with Vacuum
High pressures are not the only pressure related issue with quick disconnects. Vacuum applications can often be challenging to reliably seal, particularly on double shut-off and “dry break” assemblies. Often, the internal side of a double shut off can handle full vacuum while the external side can only handle “light” (a small amount of) vacuum. Don’t take it for granted, be sure the quick disconnect you specify offers the level of sealing your vacuum application requires."

Like afish mentioned above, I'd just use the internal volume in the base of each SE 1 unit for your vacuum reservoir, that's what I do without needing extra fittings & tubing, each connection is a potential leak point.

Six years ago I performed multiple tests using a single SE 1 base as a vacuum reservoir and all Festool QD connectors. When I unplugged the vacuum pump the wood fell off the SE 1 base in an average of 10.2 seconds. When I used the SE 1 base as a reservoir, the wood fell off in an average of 113 seconds...that's an improvement of over 10X. If you use both SE 1 bases as reservoirs, it'd be reasonable to expect a 15X-20X improvement.

[attachimg=1]

 

[jgrout]

From what I see from your video the leak(s) are anywhere after the black quarter turn valve to the vacuum head. This includes the platen the vacuum head is sitting on as it appears to be mdf that is not sealed in any way. If I were looking for leaks in the system I would start by removing the line to the vacuum head on the bench and pull a vacuum on the hose and see if it holds; I would then move further into the system checking each part by completely pulling a vacuum then shutting it off and checking each component for leakage by listening. Your leak is huge and should be easily heard if the vacuum pump is off. Bear in mind the part you put on top of the vacuum hold down will always leak as it is still in a porous state. Generally I use a piece of plastic laminate ( counter top material) as a base platen and for a cover if required to find leaks elsewhere in the system. It can be done with just a little effort.

 

[serge0n]

Judging from the video, it's your quick connects. It seems like you are using regular ones. You need high flow QD coupler and plug, like the ones in this set:https://www.homedepot.com/p/Husky-High-Flow-Aluminum-Coupler-Plug-Set-HDA22500/305303819

I had the same problem with a non-Festool vacuum clamping kit.

I managed to get both SE1 and SE2 heads in the past few months and paired them with a 5 CFM Excel pump. It works like a charm.