I finally upgraded my water heater after reading the posts from Mainsail, Stu, et. al. to a safer system. As you all have no doubt discovered the hard way, the water that comes out of the tap after using the engine to heat it is really HOT. I find this out every time I leave the handle set from when the water was heated using the electric option and then turn it on at the same setting after motoring.
I found my mixing valve on Amazon here:
https://www.amazon.com/gp/product/B00SYC1IV6/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
It was pretty easy to install, although it is all 1/2" NPS (straight threads), so you get the classic thread mismatch we are all familiar with when an improper seacock valve is mated with the through hull. In my first attempt I removed the hot water output line and fittings to be replaced with a short brass nipple and coupling. The junction of the new valve and the coupling leaked even with some pipe dope, so I went with plan B. I found at the local plumbing supply house an adapter that is 1/2" NPT (tapered) for the water heater side and a 1/2" female for the mixing valve ($4.25). Voila, no more leaks. I relocated the hot line to the mix junction and installed a push on Tee with male adapter cut into the existing cold water feed line with a braided supply line to the cold input of the new valve.
The test was to set the valve at 40 C (110 F) and heat the contents with shore power. Sure enough, with the galley faucet set at max hot, I got 110 F water. Then we motored for a couple of hours knowing the water in the tank would be scalding. I turned it on full hot and it was exactly 110 F. Just like it was supposed to be.
This was an easy project if you don't mind some water running down into the bilge while swapping and cutting lines. The pictures show the first attempt with the leaking coupling, then the final installation with the adapter.
And I have cleaned up the rust flakes that occurred from a previously unnoticed leak that ate up the mounting foot.
I found my mixing valve on Amazon here:
https://www.amazon.com/gp/product/B00SYC1IV6/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
It was pretty easy to install, although it is all 1/2" NPS (straight threads), so you get the classic thread mismatch we are all familiar with when an improper seacock valve is mated with the through hull. In my first attempt I removed the hot water output line and fittings to be replaced with a short brass nipple and coupling. The junction of the new valve and the coupling leaked even with some pipe dope, so I went with plan B. I found at the local plumbing supply house an adapter that is 1/2" NPT (tapered) for the water heater side and a 1/2" female for the mixing valve ($4.25). Voila, no more leaks. I relocated the hot line to the mix junction and installed a push on Tee with male adapter cut into the existing cold water feed line with a braided supply line to the cold input of the new valve.
The test was to set the valve at 40 C (110 F) and heat the contents with shore power. Sure enough, with the galley faucet set at max hot, I got 110 F water. Then we motored for a couple of hours knowing the water in the tank would be scalding. I turned it on full hot and it was exactly 110 F. Just like it was supposed to be.
This was an easy project if you don't mind some water running down into the bilge while swapping and cutting lines. The pictures show the first attempt with the leaking coupling, then the final installation with the adapter.
And I have cleaned up the rust flakes that occurred from a previously unnoticed leak that ate up the mounting foot.
