Plumbing fitting leak on 1988 CalSpa

[Cusser]

My plumbing fitting leak on my 1988 CalSpa is at a large plastic nut on the curved part of the now-discontinued stainless steel heater manifold where it attaches to my Hayward pump #1152UN2.  This plastic nut connects long-discontinued heater manifold HEA14100230 to the pump, and has cracked, and leaks.

 

 

 

 

 

 

 

 

I ordered some split nuts to try but none were the right size, not sure there is a correct-sized one available.  So I am trying the original nut which I epoxied with JB Weld.  I gave that 2 days to set, and found two rubber 2.75" rubber washers to replace the two that had been under the nut.  I used spa lube on all the fittings and washers.  Anyway, I filled with some water, started the pump (about 8psi) and it didn't leak, so I added more water and turned on the heater.  As the water temperature rose, I did see a leak there twice, so I tightened the big repaired nut a tad more.  The water temperature is now 100F, and I am hoping but not 100% sure that the leak has sealed.  I'm fearful of tightening more as that could cause the repaired nut to crack, if it hasn't already.

Anyway, if this doesn't fix the leak, because the manifold is discontinued, I feel my only other option would be to cut the stainless steel manifold, slide on a brand new replacement Hayward nut (these are still available) and use a short piece of 40mm i.d. automotive coolant hose to reconnect the manifold.  So I'm willing to listen to all comments, thanks in advance.

 

[Spa Board Doctor]

I think that would work but I'm not sure about the silicone hose handling the pressure on high speed. 
Maybe a traditional no hub coupling would be better?
Alternatively, if you remove the heater manifold, a muffler shop or welding outfit could weld the pipe back together.

[Cusser]

We hardly ever use the jets, which runs the pump at higher speed and pressure, but still under 15psi.  Normal running pressure on mine is 8psi with the filter in place.

Basically this is an issue of leak between two flat surfaces, sealed with two flat rubber washers. The plastic nut theoretically squeezes/sandwiches the washers enough to seal. For the first 10 years - before my 9-year-old daughter figured out I should cut a recess hole for the element - I had to remove this manifold to change the heating element (same element as in a home water heater), and I've always had issues with that connection sealing. Since then I haven't touched that fitting. I seem to remember using automotive RTV there once to seal, so that may be a good choice to try before doing any cutting if I haven't broken the plastic nut by overtightening. The funny thing: the nut has stamped on it: "hand tighten only" but even in the 1980s this had no chance of sealing. Maybe 3 washers would be better than two, or just using RTV to glue the washers together; just that the manufacturer of the spa used two flat washers for sealing this does bother me in a way...

I also thought about having that manifold re-welded if I cut it, don't know if welding stainless steel is common...

Automotive coolant hoses can handle 15psi with no issues, and 200F temperatures.

This spa - manufactured by the largest spa company in the world then - actually was quite poor at making watertight seals, but claimed everything could be disassembled without using tools !  They also had a terrible design for its filter housing and I always would have leaks there, a giant O-ring but no room to get the housing out once it was apart, a real Catch-22. My daughter and I later got a new filter housing and moved that all out of the spa cabinet, which was a great idea. The spa company and equipment manufacturer actually were quite poor at making watertight seals, but claimed everything could be disassembled without using tools !

I really don't want to buy a new spa pump/motor and use a different end on my manifold...

This is a diagram of the Hayward pump 1152UN2 I have; my #6 looks like that, flat with threads not commonly used anymore, so I can't find a split nut.  In the upper right of the diagram I don't have that #12, the manifold end flange mates to that with the two rubber washers and the #11 nut there is held captive on the manifold by the flange of the manifold.  I don't know what the outer diameter of #12 is anyway...

 

[Cusser]

My Google research shows that Hayward calls #11 SPX1500G  a "1-1/2" FBT Pump union nut" and  see a split nut available for that size (the sizes are VERY confusing), so I'm ordering that too (from Amazon because of free/easy returns) - will try anything before cutting the manifold: Magic Plastics 0121109015 1.5 FBT Small Flange Pool & Spa Pump Union Split Nut

FBT is apparently something like female buttress thread...have no idea where the 1-1/2" comes from...

Just learned that this stuff is "sized" by the inner diameter, has nothing to do with the thread size.  So 1.5" female buttress thread just might do the trick.  I went to spadepot.com and they listed two split nuts of that size, so I called and talked to their help guys, and he thinks part #BX9659 might fit, but he wants to check; so I E-mailed pictures to him.  So there might be a real fix without cutting !!!

 

[Spa Board Doctor]

I'm afraid the industry standard 1-1/2" split nuts won't fit the Hayward union - it's different.
Hayward does have a pump union with a 1-1/2"MBT molded into the end - p/n: SP1500UNPAK2
You could use this fitting on the pump then possibly one of the split nuts on the heater flange however this would raise the heater up off the pump by the height of the new Hayward union and I'm not sure that the 1-1/2" split nuts will fit around the heater flange.

[Cusser]

UPDATE: Spa Depot says the manufacturers changed stuff all the time, so they want me to unscrew the epoxied nut and take some clear close-up pictures of the pump's threads, so they can tell if they're 1.5 buttress threads; that way I won't be buying an incorrect part. This will wait until Friday morning......

 

[Cusser]

My spa does not have room to raise the manifold up like that.

Anyway, I did send requested photos to SpaDepot and this is their response:

"Thank you for the photos. The threads look like buttress threads. This heater split nut should work for you. https://spadepot.com/products/spa-heater-union-split-nut-1-5-inch-bx9659
 
Here is a link to the gaskets. https://spadepot.com/products/spa-pump-heater-oring-gasket-1-5-inch-2-pack-bx9971 "

So I bought 3 split nuts and 1 pack of gaskets. In the meantime, since I had to disassemble today to get photos for them, I used shims to better-align stuff, and put it back together; just added water, seeing what happens when I heat. I did get smart and painted a yellow spot on the epoxy-repaired nut, and I was able to tighten a full 90 degrees more today without forcing it. So we'll see what happens as it heats; I wouldn't expect the repair parts to arrive until mid-week at earliest. But if it doesn't leak, those will be retained for the future - never trouble trouble until trouble troubles you !!!

[Cusser]

Yipes - now found a leak in my pressure switch.  Removed that, and I see I had epoxied a different crack in that maybe 2 decades ago.  So trying JB Weld again....

[Cusser]

On 10/30/2024 at 4:20 PM, Cusser said:

My plumbing fitting leak on my 1988 CalSpa is at a large plastic nut on the curved part of the now-discontinued stainless steel heater manifold where it attaches to my Hayward pump #1152UN2.  This plastic nut connects long-discontinued heater manifold HEA14100230 to the pump, and has cracked, and leaks.

 

 

 

 

 

 

 

 

I ordered some split nuts to try but none were the right size, not sure there is a correct-sized one available.  So I am trying the original nut which I epoxied with JB Weld.  I gave that 2 days to set, and found two rubber 2.75" rubber washers to replace the two that had been under the nut.  I used spa lube on all the fittings and washers.

 

On 11/2/2024 at 10:07 AM, Cusser said:

Yipes - now found a leak in my pressure switch.  Removed that, and I see I had epoxied a different crack in that maybe 2 decades ago.  So trying JB Weld again....

 

Good news !!! The JB Weld has appeared to have sealed both the large nut and the flow switch, no leaks there.

Bad news - spa is leaking somewhere that's not in the equipment section; one side of the spa is inaccessible due to home's block wall being 8 inches away, and all the plumbing PVE pipes and hoses are encased in expandable foam so horribly tough to even get those panels off or to find source of such leak or leaks, or even fix such leak(s) should I be lucky enough to find it/them.  So my last ditch attempt may be the Marlig Fix-a-Leak, which I've used for about a decade and claims to seal leaks up to 1/8 inch....

 

[Cusser]

On 11/8/2024 at 12:17 PM, Cusser said:

Bad news - spa is leaking somewhere that's not in the equipment section; one side of the spa is inaccessible due to home's block wall being 8 inches away, and all the plumbing PVE pipes and hoses are encased in expandable foam so horribly tough to even get those panels off or to find source of such leak or leaks, or even fix such leak(s) should I be lucky enough to find it/them.  So my last ditch attempt may be the Marlig Fix-a-Leak, which I've used for about a decade and claims to seal leaks up to 1/8 inch....

 

I dug out more old foam, could actually feel water leak, but could not actually isolate exactly where it's leaking, exploring from two sides; apparently the leak is NOT on the side blocked by the house, but in the corner of the spa.  Bad news is that I'd have to cut out a panel to even try to access.  Just above the leak are two nozzles for air jets, might possibly be leaking around the circumference of one of these to the spa shell.

Anyway, I already "rebuilt" the redwood two panels I had removed to explore this, and I've used the Marlig Fix a Leak to stop or slow the leak to a manageable amount that I can live with, with a 36-year-old spa.

Next time water is drained, I might try marine epoxy around the two air jets I suspect.  Anyway, spa is usable and Mrs. Cusser and I enjoyed it last evening, with wine....

 

 

[Cusser]

Update Nov. 25:

Still OK, yay !

I imagine I spent about 20 hours on and off getting this going, had to be patient for the JB Weld to fully set, looked into alternatives to the flow switch, alternative to the discontinued stainless steel heater manifold, waiting for the Fix-A-Leak to do its stuff.

I also figure that even if I found a spa repair professional, he wouldn't take the job and certainly wouldn't guarantee it. So in hindsight I feel my way was best.

 

[Cusser]

Update May 20, 2025:

Still OK, yay !