Major Corrosion On Almost New Pressure Switch

[overlandsea]

Hello, I am having some trouble with my hot tub (Costco sold Imperial Windsor…made by Jacuzzi is my understanding, probably 10 years old now) and was wondering if I get some feedback from other who are more in the know.

Hot tub started GFCI tripping only when heater turned on. I went to remove the heater (mounted directly behind electrical box) and had to remove the pressure switch first as it is mounted through the electrical box into the heater. When I did this it simply broke off and I found that the part inside the heater had basically crumbled/rusted. Now this part is only a few months old. I replaced the previous one because of flow error messages when there was indeed flow. This one had a decent chunk eaten out of it where the water contacted, but I assumed this was from years of use. This one completely crumbled in only a few months.

This doesn’t seem to be a common problem I can find elsewhere, but here is my hypothesis, please let me know if it is accurate or not: Previous corrosion of pressure switch also affected the threads in the heater. This new one never had a perfect seal because of that, so slight water leakage and contact with the grounded outside of the heater caused the corrosion. More corrosion = bigger leak. This progressed to the point that it caused arcing current that tripped the GFCI. If this is true, then my understanding is simply replacing the heater and pressure switch would solve the problem.

There is very limited corrosion on the outside of the heater. None that I can see at the electrical terminals, though oddly at the mounting studs, though this might make sense because I think that these are also the grounding points for the heater (attach to electrical box), there is no grounding wire or lug with this heater.

There is a very small amount of corrosion on the heater element itself, and much more on the inside wall of the heater sheath/cover right by the pressure switch, and looks perhaps like there is arcing marks there.

Thanks in advance!

[overlandsea]

Corrosion from pressure switch

Inside heater (pressure switch side)

Small amount of corrosion on heating element (other side)

[PreservedSwine]

If the GFCI is tripping, replace the heater. Buy one with a pressure switch already installed, only a slight price increase. It's possible the heater body is corroded badly enough in the threads to still leak, though it's fairly unusual.

The GFCI tripping is likely coincidental, as the element itself has likely developed a ground fault. A small amount of water coming from the Press/sw threads won't trip the GFCI, unless said water is landing on something it inside the control box. It would take water penetrating the rubber diaphram inside the pressure switch, and leaking through the pressure switch terminals to have any chance at tripping the GFCI.

[overlandsea]

If the GFCI is tripping, replace the heater. Buy one with a pressure switch already installed, only a slight price increase. It's possible the heater body is corroded badly enough in the threads to still leak, though it's fairly unusual.

The GFCI tripping is likely coincidental, as the element itself has likely developed a ground fault. A small amount of water coming from the Press/sw threads won't trip the GFCI, unless said water is landing on something it inside the control box. It would take water penetrating the rubber diaphram inside the pressure switch, and leaking through the pressure switch terminals to have any chance at tripping the GFCI.

Ok, that makes sense. Any idea why the pressure switch corroded out so fast?

[PreservedSwine]

Keep a close eye on your water chemistry. Don't over-sanitize, and don't let the PH get too low. When your water is not balanced, the pressure switch and heater are typically the 1st things to corrode, as they are the only components made completely of metal.