The plumbing in our house was one of the worst things we had to deal with. So bad that the city building inspector called in the state plumbing inspector, who told us it one of the worst cases he’d ever seen. In addition to the tangle of incorrectly routed drains and vents, we had burst pipes and fixtures all over the place.
The cold took its toll on the two hot water heaters we inherited with the house, too. They were completely shot, so we opted to replace them with a single high-efficiency tankless water heater. Whatever our plumber’s other faults, he isn’t afraid to buy quality stuff. He installed a Rinnai (model R75LS), which seems to be the most well-respected brand out there. We’ve been using it for almost two months now, and no complaints. It runs beautifully, and I expect to see some solid energy savings this winter.
Install didn’t take him very long, but later that day we noticed that the water wasn’t very hot. I checked the panel, and it was set to 104 degrees. I tried adjusting it up, but couldn’t get it past 120. That’s been reasonably hot, but we’ve got some more heavy-duty cleaning ahead of us – and temps above 130 are a little more useful for scrubbing and disinfecting.
I asked our plumber about it, and he explained that 120 degrees was the default maximum. “They don’t let us set ’em any higher than that,” he said. “If we adjust it up, I can get in trouble with my license. But you can set it as high as you like. Just read the manual.”
The instruction manual wasn’t super helpful, actually – no nicely-illustrated how-to headings. It told me that I’d need to change a dip switch in order to up the maximum to 140 degrees, but it didn’t tell me where the dip switches were. Nothing obvious on the outside of the heater, and nothing useful on the interwebs, so I figured I’d have to take the cover off and poke around. No problem. It was time for another DIY project anyway – even if it was a light one.
First thing was to turn the heater off and remove the cover. It wasn’t obvious, but simple enough: there are four plastic tabs in each corner.
Each tab pops up pretty easily, exposing the screw underneath.
Get those out of there, and the cover comes right off, exposing all the glorious water heater guts.
See any dip switches in there? I didn’t, either. Fortunately, there was a wiring diagram on the back side of the cover, which at least gave me a good idea of where to look. The tiny little buggers were hiding underneath a loose plastic cover in the lower right corner of the cabinet.
The manual said I’d need to flip switch #6 to up the maximum water temperature. My clumsy fat fingers somehow got the job done.
Then I spotted a note in the manual about elevation: for any altitude higher than 2,000 feet (Deadwood definitely qualifies), at least one dip switch should be adjusted. I checked, and… they were set to the default. My arch-nemesis the plumber strikes again. So I fixed that one, too. Viola.
I popped the cover back on, turned on the power and tried adjusting the temperature. Success! It went above 120.
I kept it up until it wouldn’t go any higher – 140 degrees. Perfect.
Next step was to run upstairs to the kitchen and do a real-world test. It takes a while to get the hot water into the pipes, but pretty soon it was coming out of the tap a little steamier than usual.
All told, a 15-minute affair. Easy stuff. Should make cleaning a lot easier… and the baths a bit hotter. Now, if we can just get our clawfoot tubs cleaned up…