Any Plumbers? Swissflow 800 Thread Question

[LBussy]

I am installing some Swissflow 800 flowmeters and they state they are 3/8” BSP Male (not BSPP and not BSPT) threads. The only fitting I could find is the DMfit Female BSPP Connector Cone Type - 5/16" Push-in x 3/8 BSP(P) which is apparently parallel threads. The DMfit pieces have a gasket in the seat.

I think - I'm pretty sure, no Teflon tape or sealant is required or even recommended. The pieces tighten together fairly easily and feel like they are seating against the gasket. I'm just looking for someone who might have come across this to confirm my suspicions.

 

[LBussy]

Well, I received an unbelievably fast response from Swissflow to the email I sent them at the same time. They confirmed these are BSPP threads, so I answered my own question. Leaving this here in case someone else is searching and needs the information.

No Teflon tape!

 

[Deadalus]

I wonder if in general there is a tendency to just use BSP for BSP(P)? The BSPP type threads are used in many Commonwealth countries for plumbing pipes from what I have read when reading into this topic. Maybe products from there (and even Europe) simply use BSP?

Beer faucet shanks are often BSPP. I used to wonder why that was so because I didn't understand where the taper referred to. I thought it was the individual thread shape itself but the parallel (straight) and taper refer to the progression of the threads along the pipe (or rod). It makes sense now given their usage where the overall length needed can vary and both ends need to be the same size! (Mechanical engineers are probably thinking, oh man this guy...).

I don't know how measurable the taper is, but with a male part, one could measure a threads on opposite ends and see if they differ (digital caliper). This link has some helpful graphics.

 

[day_trippr]

fwiw, I'm back home, Lee. And I used that exact same DMfit part when I retrofitted my 2nd keezer with EVAbarrier tubing. Had to look up the morebeer order to be sure.

As long as the rubber gasket is in place (it can fall out!) it's a trouble-free connection to the SF800 meters - no tape required (or desired - tape would likely screw things up instead of helping)...

Cheers!

 

[duncan.brown]

Are you guys sure that you want BSPP cone fittings? The John Guest connectors on my SF800s are BSPP flat.

With a BSPP flat connector, the mechanical seal is made by friction between the parallel threads and the liquid seal is made by the rubber washer inside the female connector (the JG connectors come with the washers). Since the threads do not get deformed when the mechanical seal is made and the liquid seal is on the rubber, no teflon tape is needed (in fact, it would be bad as @day_trippr said).

 

[LBussy]

Are you guys sure that you want BSPP cone fittings?

Well, I posted in the other thread before I bought these. They had better work because buying fittings over and over again is expensive.

Good to know though, in case I need to figure out leaks. For now, it works.

 

[duncan.brown]

If the interior opening of the SF800 is large enough for the BSPP cone stem to fit inside, I think you'll be fine. With a BSPP connector, if the seal isn't being properly made on the washer, you'll find out pretty quickly!

 

[LBussy]

These are 3/8" thread x 5/16" PTC, so those part numbers don't line up. Freshwater Systems has been REALLY bad about answering emails, so I'll try to call them.

 

[duncan.brown]

I posted the John Guest part numbers. Here's what you're looking at from DMfit, I believe

https://dmfit.it/en/fabg-female-ada...hread-cone-type-5-16-x-3-8-8000000002204.html

 

[duncan.brown]

@LBussy I took the calipers to one of my spare SF800s and they are definitely parallel thread. The minor thread diameter is 14.9mm and the major thread diameter is 16.2mm, which matches BSPP 3/8" to the accuracy of my crappy home calipers. I've also attached pictures of my JG fitting with and without the washer. I use 3/8" OD on the PTC side, as I'm using Bev Seal Ultra 235 not EVA Barrier.

 

[LBussy]

Thank you for checking that.

Yes, I can find 3/8" PTC but that 5/16" is elusive in some form factors.

 

[duncan.brown]

Yes, I can find 3/8" PTC but that 5/16" is elusive in some form factors.

Yes, It looks like John Guest doesn't make a matching part and DMFit only has 5/16" PTC to BSP in the cone end, not the flat.

 

[skidmark]

FYI --

BSPT = British Standard Pipe Tapered = ISO 7/1 Rc

BSPP = British Standard Pipe Parallel = ISO 7/1 Rp

 

[LBussy]

Okay I'm not sure if these are new, but I have found the BSPP flat fittings for this:

DMfit Female adaptor OD Tube - BSP thread (Flat Type) 3/8" x 5/8, SKU: AFAB0608F

Fresh Water Systems has them here.

Not sure how I missed them originally ...

For those who just want to get back to 'murican, @Thorrak found these:

BSPP Adapters - Stainless Steel - 3/8 Inch Male NPT x 3/8 Inch BSPP Female With Sealing Washer, SKU: SS304038MNPTX038FBSPPX/ORINGBONDED038X

Pricey, but it's an option.