Leaking Adjustable Pressure Switch

[FuzzyGrub]

I went to refill my tanks this AM, and found my SB Max would not get above 1000psi.      I first suspected it was time for a cyl rebuild, but once I shut-off, heard the leak.  Traced it to the adjustable pressure switch. It is leaking between the brass and aluminum fitting.   The switch came from MC and fairly certain that it was used on the F8.  Price is $100 and leary to buy another  when this one failed with relatively light use.   Looking at a picture of the F10, it looks like the switch has changed.  I found similar looking one at Zoro, but not right pressure range.   Does anyone know of a better replacement? 

PS: I'll contact Tom and Carol and see what info they can provide.

In the meantime, I plugged the hole with a 1/8" NPT 0-6K gauge, alone with a jumper wire, and seem to be back up and running. 

https://www.mcmaster.com/3427K83

[AlanMcD]

Sorry to hear your trouble with this John,

In fact, I am doubly so, as I was thinking of using some of the spare time resulting from working from home to make your upgrade on my Shoebox Max (still just running it with the timer to stop it).

Glad you were able to easily bypass it. If you want a good timer for controlling it to the minute for a calculated shut off time (for safety, in case you miss your shut off time), this is the kind I use: 

I will be interested in what Tom and Carol have to say.

[FuzzyGrub]

Well, I took my back-up hand pump to camp a few weeks ago, and all three of my tanks were below 3K.  Some how I was going to get this running. 

I got a quick and detailed response from them.     Their support has always been top-notch,  If F10's were still available at $500, I'd have ordered one today. 

They provided me with the specific model and mfg of the newer F10 switch.  Now, unlikely they will sell a single unit, but I appreciate the info.  They also indicated they had a few in stock and price is close to the MC one.

The 2nd option, is a repair kit for $5 that they made.  This suggests there have been problems with it.  The caveat is you need a lathe to take it apart.  I can tell you that my long handle wrenches were not getting anywhere.     I have asked for some additional info on that, and might give that a try. 

I originally installed the switch to get away from the clacking, and to be able to fill guns or tanks.  I never ended up filling guns much, so little use for the adjustability.   I already have a 0-1Hr timer, which provides good back-up if I get distracted and walk away.  The 1st stage compressor is a CAT, so quiet enough to be in the same room.   So, not sure I'm going to spend another $100 for a switch just yet.

[FuzzyGrub]

Turned out the lathe was just to use the chuck to hold it.  I feel stupid.      No chuck here big enough, just heavy duty water pump pliers, a vice, and long handled box wrench, and a bit more elbow grease.  There is a small white disk that looks to be a seal, which going ahead and ordering the repair kit.

I also found a surplus pressure switch at a reasonable price, so ordered that as well.

[FuzzyGrub]

I received the kit from SB.  Turns out there is a BN O-ring under the white material, which just sandwiches it.  The kit includes a poly replacement O-ring and a metal backer bushing. 

Again, absolute phenomenal support by the SB team.  I received the kit yesterday morning and sent a question in on the install.  Within an hour had the picture and answer, and it was an east coast AM question with west coast answer. 

Still waiting on the arrival of the Ebay pressure switch and will test both.

[Madd Hatter]

Is this the same pressure switch they use in the F10?

[Taso1000]

Hey John!

Thank you for creating this thread!  This is great information to know in advance for us Shoebox owners.   

Taso

[FuzzyGrub]

Is this the same pressure switch they use in the F10?

No, it uses a Gems PS71-60 variant. 

A similar pressure switch was used in the early F8's, then switched to the Gems.   My guess the change was prompted by the leaking issue, that they developed this kit for.   Taso has the same switch.  I got the MC part# info from its prior owner.   

[FuzzyGrub]

The new/old stock Gems pressure switch came today.   Looks like the same as in spec sheet.  Away for the weekend, but will test both next week.

[FuzzyGrub]

Just to close out this thread. 

I was able to test the Ebay Gems PS71-60.  At first, my heart sunk when trying to adjust to 4500 psi switch opening.  It would not go above 3500 psi.  Turns out there was a grub screw that had to be removed to reach the "real" adjuster.     Like Mrod TP adjustment.    Just cost a little more time and pipe tape.   While shorter than the other switch, the hex head on it is 1 1/8" vs 1 1/16".   I had to adjust some of my plumbing, but that only pertains to the way I ran it.  $20 for a new switch worked out fine.     https://www.ebay.com/itm/Gems-PS71-60-4MNS-B-FLS18-Series-PS71-General-Purpose-Mini-Pressure-Switch/333542706934?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

I then tested the old switch with the new seal kit from SB.  No leaks!     Made a minor adjustment in the shut-off pressure.  Back in auto-shut-off operation.