Intex Inflatable Spa Plumbing Caps

I’m working up to finally posting about my adventures in DIY hot tub land, but for now I’ll be brief: we have an Intex inflatable spa, and I do a LOT of DIY mods to it that require plumbing access.

Since I don’t want to drain the whole tub every time I mess with the pipes, I present: Intex PureSpa Plumbing Caps.

Blower Inlet Cap

The bubble plumbing has a check valve internally, so it won’t gush water when you unscrew it. And if it eventually leaks, the OEM pump assembly has plumbing like a dishwasher so it can’t leak into the blower motor:

Unfortunately, my OEM pump module is long since kaput and I don’t use it at all anymore, so the blower circuit is just sitting there open and unused. Even before mine started leaking, we have lots of spiders and other critters in the back yard. Maybe they’re even why it’s leaking, who knows. But it needed a cap, so I made one.

Dimensions and Assembly:

CAD model here on thangs: https://than.gs/m/1025505

I drew in CAD this plug with a 2.375″-12 thread extruded 15mm (not critical) then scaled 98.5% X/Y and 118.3% Z to match the as-measured 10.14TPI thread pitch with a decent fit. I couldn’t ever figure out what the thread is ACTUALLY supposed to be but this works. It doesn’t seem to be a standard metric OR imperial, but Intex HQ is in Long Beach CA so I suppose it’s more likely to be in inches.

Fits well, but even with ironing on the interior mating face, it doesn’t seal well enough. I bought this 1/16″ silicone gasket sheet on Amazon and cut a 58mm circle out of it to put in the bottom of my cap, and that seals it up nicely. I printed a little ring to stamp the 58mm into the sheet by stepping on it, so I’d have a template to cut with scissors.

Filter Circuit Cap

When you undo the plumbing for the filter/heater circuit, water DOES immediately start gushing. By installing these caps, you can completely remove the filter/heater/blower assembly for cleaning or whatever else, without any water leaks. You’ll need 3, one for each filter inlet and one for the return. Remove both filters and cap all 3 spots internally.

You may need to print two more for the outside ports to keep things really dry if you’re going to leave the plumbing disconnected for a long time, as the inside ones don’t seal very well (probably – I haven’t actually had a chance to test these yet).

These were drawn as 1.75″-12 thread extruded 20mm (at least, important!) and scaled 104.5% in X/Y, and 93.8% in Z to match the measured 12.79TPI thread pitch. It’s important that the thread is long enough so the TOP surface bottoms out on the inside of the hot tub wall.

Thangs link: https://than.gs/m/1025509

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