Installation - On Demand Water Heater . Before going into too much detail, I'll first clarify the two different terms used on this page when refering to pipe threads, those being Straight and Tapered. Straight is also refered to as NPS and tapered as NPT. The confusion is that some plumbing supply stores use NPT as meaning National Pipe Thread (also correct) and just call out either NPT straight or NPT tapered, but some refer to them as just NPS or NPT. The image below should explain the slight difference between the two.
. Any good hardware or plumbing supply store is usually happy to help you with any questions you might have. Your installation will probably differ from mine. So now, here's what worked for me. ______________________ . The hardest part of the job was just removing the old hot water heater. The new unit is very light, so it was easy building a nice mounting for it. Here is the basic frame. I shimmed it out even further, exceeding proper clearance. Though not required, I used metal sheeting (not shown here) for extra insulation. You can see it on the last image.
Just needed the standard washer hook-up supply lines, plus some nipples and adapters to step from the existing 3/4" copper flex to the 1/2" connections on the unit. I got quality brass nipples and adapters. Here's the exact setup I needed.
The brass nipples and adapters are needed to mate from the 1/2" supply lines to the 3/4" copper flex. The only Teflon tape required was to mate the nipple to the adapter on each supply line. On the copper flex lines, it's really important to replace the washers. If buying new copper flex lines, they will be okay, but the washers on the existing copper flex will probably need replacing. And they are not just any washer, like a simple washer for a hose fitting (left). They are instead a very heavy-duty tall-profile washer, about a dollar in price. Here is what they look like (right).
Regular water heaters use standard 3/4" tapered thread connections of brass or galvanized. The 1/2" threaded connections of this new unit are straight, not tapered threads. They require no Teflon tape or pipe dope, just a washer. The flat threaded end on the unit connection seals against the washer when tightening the supply line. Same thing at the other end of the supply line where it joins the nipple. But Teflon tape or pipe dope should be used to join the nipple to the adapter since the threads are tapered. Take care to wrap (or dope) two or three threads up from the end. You don't want any Teflon tape or dope getting in the water line. The next images show why it's a good idea to inspect your old copper flex when breaking the connection for the install. The old washer is usually brittle and disintegrated some. Breaking the connection and then just tightening again without a new washer will probably result in it leaking.
Put a small amount of Vaseline on the rubber before tightening it down. It will make tightening a little smoother, giving it a better seal. With this type connection, there is no guesswork as to when it's tight enough. It will clearly stop when tight, allowing maybe a quarter turn more. That's it. This applies to both ends of the supply line, the other end being where it meets the nipple to join the 1/2" to the 3/4" brass adapter. Again, no Teflon or pipe dope needed. Just remember to use a little Vaseline on the rubber washers before tightening. On the gas connection, be sure to use the yellow Teflon tape since it's heavy-duty and specifically made for gas. Building codes in some areas may require it. Always check for leaks on the gas connection by brushing on thick, soapy, water. Look for bubbles when the gas valve is first opened following the install. Do not apply AC or battery power to the unit until this is checked.
On the venting, I just used my existing vent system to comply with code. I have a friend that's a plumber and he said these units are starting to pick up in popularity. In fact, it's cutting into their business (and profit) since homeowners can install it themselves. Installation Completed
. Most units on eBay are standard units from a factory in China. The units Justin sells aren't these same standard units. He has upgraded some of the internal parts, using parts from Japan to get better quality. The unit he offers now is the only unit on the market where the middle connector (hot-out) is extended about an inch longer, making it much easier to install. It's also nice having the plug in AC option as well. If you decide to get one, Justin is the way to go. I've done a bit of trading on eBay, and he's one of the best persons I've dealt with. __________________________________________________ .Troubleshooting Tips
My setup is probably different than the average, especially since I installed
an additional cut-off valve on the hot water out connection. I also used
galvanized nipples to join two flex lines to get more length. I happened
to have them already, so decided to use what I had. You can buy flex lines
at greater length, which would be recommended. Since installation, 7 months
now, there has not been one single drop.
Should you encounter any problems, the following might help you correct the situation. No Hot Water - If using the battery option, make sure they have a sufficient charge. Replace with new if you're not sure.
I have a light colored linoleum floor which makes it hard to spot any small leak. And since I have the extra cut-off valve and extended my flex lines, that gives me a total of 14 threaded connections that could leak. I could easily miss a very small leak. A drop an hour would evaporate before I could catch it. A good trick is to place a large piece of cardboard directly under the install (as shown below) as even one drop will show clearly. If it dries, it will be raised and slightly discolored, still making it noticeable. If you don't have a large piece of cardboard, you can use a large brown paper bag. The image below shows what has been sitting in place for several months now, so I'm confident there are no leaks.
__________________________________________________ . Update I recently decided to upgrade to the larger 12 liter unit that Justin offers. This gave me a chance to see how the extra valve I installed on the hot water out line worked.. It really made a difference. After closing off both valves, there was less than a quart to drain from the 6 liter unit. Here are a few images showing the upgrade, which took less than an hour to complete.
Here's the new 12L unit Installed.
I decided to use the AC adapter for starting and just use the battery option when needed. I like having the temperature reading on the front of the new unit. This new unit meets all specs, giving me great pressure, volume, and temperature. In fact, I've had to adjust my volume and temperature settings down to mid-point. As I mentioned, the upgrade took less than an hour and went easily. The old days of mopping the flooded floor when the huge, expensive, bulky, energy wasting, water heater failed are gone forever.
If you have found this page by surfing the net, the Justin I mention is user
Goldstar33 on |
|||||||||||||||||
. You
can visit his website at
.