Product Review and How To Install an A. O. Smith GDVT 50 101 Propane Water Heater Off Grid

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Wow. Off grid, propane water heater, etc.–that’s a lo-ong title! But for the 50 gallon A.O. Smoth GDVT 50, this is an installation (how to) and product review (how it do) page. How on earth can I shorten the thing?

Never mind. There’s no time to figure that out. This needs to Publish by daylight, and we’ve already lost several hours due to lost connectivity with this website. Turned out there was a router out there somewhere in the middle of the Internet that had a problem….

Okay. Down to brass tacks.

I built an 8′ x 8′ back porch aka water heater shed aka tool shed, primarily to house the new hot water producer. We live off grid, and with that in mind, I had built and installed a passive solar hot water heater system in 2012…which worked well, but not quite well enough. My wife is deeply disabled on a number of fronts and let me know in no uncertain terms that having to (a) time her showers or soaks for late afternoons when the water was warmest or (b) settle for lukewarm water in midwinter–well, that was simply not acceptable.

Hey, happy wife, happy life.

However, choosing the specific hot water tank to suit our needs was not a simple proposition. An on demand tankless heater seemed logical, but none of those will tolerate having the water pre-warmed (by the solar system) before it hits the tankless unit. They’re just not designed for that.

That meant I needed to come up with a quality “regular type” water heater that had the following specific qualities:

    1. Fifty gallons of capacity. Thirty gallons would have probably worked well enough, but trying to convince Pam of that wouldn’t have been worth the effort.

    2. Standing pilot light. A lot of Internet writers ridicule those, citing the amount of propane used to keep the light lit year ’round, but I prefer them. We had a pair of 40 gallon heaters in Montana that only lit on demand, but one of the automatic piezo igniters wore out within a year’s time. Fooey on that. An igniter is okay to light the pilot, but once it’s lit? I say let it stay lit.

    3. Side vent. That is, a venting system that shoots out through one wall of the building it’s in rather than punching a hole in the roof. I’m a big believer in not putting holes in roofs if said holes can possibly be avoided.

    4. Outside air supply. Numerous horror stories can be found on the Internet (if you look hard enough) that focus on problems stemming from the heater’s burner flame needing to draw its air from near the floor where the tank is installed.

    5. American made. We buy plenty of Chinese goods from Walmart, but when it comes to major home appliances, give me the red, white, and blue every time.

    6. Propane powered. Any heavy electrical draw is a serious consideration when you live off grid, relying on a small portable solar generator and a variety of portable gasoline generators.

That’s a long list of deal killers, right there. It’s sort of like a guy listing all the attributes his ideal woman must have, leading him to conclude Mommy was right; there’s no girl out there who’s good enough for him!

Thankfully, I did find one tank–and only one–that met all six requirements. Or…close enough. The A. O. Smith GDVT 50 101 boasts online that it’s made in America, but the label on the unit itself turned out to admit it was Made in Canada.

Hey, it’s North America, at least. We’ll go with that.

Hauling the new A. O. Smith GDVT 50 101 water tank back from Tucson (in the small box).

Hauling the new A. O. Smith GDVT 50 101 water tank back from Tucson (in the tall box).

The nearest dealer for A. O. Smith tanks was in Tucson, Arizona, a couple of hours away from our down-on-the-border acreage. They had to order this model in for me–it’s pretty specialized, and expensive, too, in the $1,700 range–and when it arrived, our GMC pickup truck and I trundled on up to haul the new beauty home.

Not that I really knew yet if it was a beauty or not, since it was still in the very tall box. All that height made it tricky, driving into the wind; 55 mph was Mach 9 as far as that box was concerned.

But we made it and, when the new addition to the residence was completed and ready, it was time to do the installation.

Cutting it out of the shipping box was a chore. Beyond that, the first examination of the tank itself was sort of a mixed bag. Though essentially tall and pretty, the skin of the tank had been somewhat abused during shipping. Paint had been rubbed off, down to bare metal in a number of spots. There was one noticeable (though fortunately not deep) dent.

I had to think about that dent for a while…but then I realized the dent in the skin would have been absorbed by the insulation between the outer layer of metal and the strong inner tank. So, except for aesthetics and a mild case of irritation, no harm, no foul.

It certainly wasn’t going back to the wholesaler. I’d worked too hard to get the thing home.

Beyond those minor scuffs, some of the design features were interesting. From the top of the tank, a three inch exhaust pipe blows heat out. Surrounding the exhaust column is a larger pipe that sucks in air, which travels through a chamber down the outside of the tank to the burner. The flex piping that runs from the tank to the wall keeps the inner and outer pipes from hitting each other by installing several springs that keep the spacing between pipes more or less even.

Well. Time to set this new beast where it was going to live for all time, get it leveled up, and (after a trip to Home Depot) get the vent itself mounted through the wall, the vent piping run, and the gas piping run.

Uh-huh. Sure. One thing at a time.

Cutting the new A. O. Smith hot water tank out of the box was a challenge.

Cutting the new A. O. Smith hot water tank out of the box was a challenge.

The vent that goes through the wall.  Note the inner pipe (hot exhaust) and outer pipe (incoming cool air).

The vent that goes through the wall. Note the inner pipe (hot exhaust) and outer pipe (incoming cool air).

At first glance, the double tubing looks like a giant Slinky.

At first glance, the double tubing looks like a giant Slinky.

It was the first time I'd seen one of these tanks with the cold air shroud surrounding the hot exhaust pipe before meandering down off  the side of the unit.

It was the first time I’d seen one of these tanks with the cold air shroud surrounding the hot exhaust pipe before meandering down off the side of the unit.

There were spots where the paint had been scraped off during shipping...pretty much all over the tank.

There were spots where the paint had been scraped off during shipping…pretty much all over the tank.

Another trip to Home Depot, in part for a can of Rustoleum spray paint to cover those scraped spots.

Everywhere you can see a gray spot, that's Rustoleum covering a shipping scrape.

Everywhere you can see a gray spot, that’s Rustoleum covering a shipping scrape.

Next, the tank needed to be leveled. Had I done a better job of pouring the concrete pad, that might not have been necessary, but….

Leveling the tank (using split wood shakes) was a simple, painless process.

Leveling the tank (using split wood shakes) was a simple, painless process.

With the tank leveled, it was time to cut into the hot water line running from the passive solar system to the house. This turned out better than I expected. I’d figured there’d be a lot of water to drain, but there was hardly a drop. (Yes, of course I shut the supply line off first. Did I forget to mention that?)

The hot water supply line from the solar system to the house is cut open.

The hot water supply line from the solar system to the house is cut open.

Plumbing the water lines was pretty simple. To my astonishment (in a good way), Home Depot had CVPC fittings with rubber washers inside, a perfect fit to match up with the tank’s iron pipes. I added Teflon tape anyway, but still.

While I was at it, including shutoff valves on both the incoming and outgoing sides seemed like a good idea, so why not?

A 3/4" CVPC fitting with rubber washer, designed to match up with the hot water tank's iron pipe.

A 3/4″ CVPC fitting with rubber washer, designed to match up with the hot water tank’s iron pipe.

The A. O. Smith tank is now inserted into the hot water plumbing run, complete with shutoff valves on both the incoming and outgoing sides.

The A. O. Smith tank is now inserted into the hot water plumbing run, complete with shutoff valves on both the incoming and outgoing sides.

With the water portion of the plumbing done (and after the CVPC glue had set overnight), the valves were opened and the tank filled, allowing the air to exit through the hot water faucet in the utility sink. We then knew that part of the job was working right. Equally important, the weight of the water of the tank made it stable, unlikely to joggle out of position while I was running the vent or gas piping.

Now for the venting arrangement. By sitting one end of the flex vent piping atop the tank (where it would eventually rest permanently), holding the other end up to the wall, and bending the pipe (by hand, easily done), it was simple enough to figure out where the hole had to be punched through the wall for the vent. First, a 6″ circle was scribed on an ordinary piece of copy paper with a compass (the pass-through pipe is actually a bit less that 6″ in diameter). The paper circle was then cut out with a pair of scissors and used as a template to mark the wall piece that needed to be cut out.

At this point in the development of our homestead, we’ve acquired a dizzying array of power tools, two of which were used to cut the hole and mount the vent.

1. The DualSaw made the first plunge cuts to start the hole making process.

2. The jig saw leapt into the first hole and finished going around the outer circle.

The vent fit through the hole perfectly and was mounted with four long screws (provided).

The paper template.

The paper template.

The mark for the hole in the wall.

The mark for the hole in the wall.

The mounted vent (inside view).  The flex pipe is hung from a rafter with care, hoping hot water soon would be--well, not there, but in the tank.

The mounted vent (inside view). The flex pipe is hung from a rafter with care, hoping hot water soon would be–well, not there, but in the tank.

The vent (outside view).  This part of the task was finished by flashlight.

The vent (outside view). This part of the task was finished by flashlight.

As long as I was punching holes in the wall, might as well include one for the propane hose to pass through.

Yeah, we do understand that code compliant installations use black pipe, not black RV type flex hose. So? Everything we have here is “RV style”, thanks to Arizona’s misguided statute that won’t allow large (500 gallon) tanks to be dropped and filled by dealers unless all installation of appliances has been done by licensed contractors. It’s B.S., but you deal with what you got–so we make do with flex hoses and 100# portable propane tanks.

After the propane pass-through hole was fitted with a piece of 1 1/2″ PVC pipe, R13 insulation was added all the way around (except on the house wall side and, of course, the door). An interior wall (OSB strand board) was installed to cover the insulation.

The propane pass-through pipe, exterior view.

The propane pass-through pipe, exterior view.

Insulation being added.

Insulation being added.

Walling it up.

Walling it up.

When the venting was installed, there was one glitch. The wall ends of the double flex pipes (exhaust inside, cold air outside) have bits of metal that are obviously supposed to snap into a particular groove in the vent pipes, locking them together–but that didn’t happen. There are ridges on the vent pipes (both inner and outer) that block the forward progress of the lead edges on the flex pipes.

Manufacturing boo-boo, for sure…but not a problem in our case. The precise positioning of the tank in relation to the wall produces a fairly strong “forward push”, especially with one metal screw securing the pipe at the tank end. It’s not even necessary to use hangers to hold up the flex pipe run; everything is stable without that.

The final combination exhaust venting and air intake arrangement, according to directions.

The final combination exhaust venting and air intake arrangement, according to directions.

January 7, 2014. This project had been under way since before Christmas. There had been many interruptions, but today was the day. The final plumbing, the gas line between the propane tank and the hot water tank, had to be run–and that was it. With any luck, we’d have city style hot water before sunset.

And we did. Starting at the water tank end, a yellow flex pipe designed for propane was fitted to the control box on the tank at one end and to an iron sediment trap T-pipe at the other. From there, the rubber hose ran through the wall (pass-through PVC pipe) and into a regulator that screwed into the brand new (and topped-off full) propane tank.

Each fitting got a double wrap of yellow gas-compatible Teflon tape and plenty of wrenching (using either pipe wrenches or adjustable (Crescent) wrenches as the situation required.

The gas was turned on. Sniff test…no leaks. Soapy water test…no leaks.

So far, so good.

The flex pipe run between tank and wall.  Note the iron pipe sediment trap hanging on said wall.

The flex pipe run between tank and wall. Note the iron pipe sediment trap hanging on said wall.

Rubber hose and an RV style regulator.

Rubber hose and an RV style regulator.

Hooked up and ready to rock.

Hooked up and ready to rock.

It was time to light the pilot.

The instructions are printed right on the tank; there’s no need to repeat them here. One cool feature, however: If you lie down on the floor (the only way I could accomplish this) while lighting the pilot, there’s a glass window (about an inch square, maybe an inch and a half) through which (after removing an outer cover) you can watch the piezo igniter (push button) spark and the pilot light take hold.

For a first lightup, patience is required. It took several minutes for the air to bleed out of the line. But once the pilot lit, everything was good to go.

Strangely, the thermostat dial does not list the heat settings in degrees; there’s only “1”, “2”, and “Very Hot”. I have no idea why they did it this way–unless they figured today’s average consumer would get confused by those big Fahrenheit numbers or something–but I set the dial at 1 1/2 and waited to see how things were going to work out.

It took one full hour before the burner turned off, which surprised me a little. I’m used to faster propane water heating than that. But then, were those other tanks 50 gallon models?

Uh…no, they were not. They were usually 30 gallons or less, installed in mobile homes.

Why A. O. Smith made this hot water tank dial so challenging to read, I have no idea--nor why there are no Fahrenheit numbers, just "1", "2", and "Very Hot".

Why A. O. Smith made this hot water tank dial so challenging to read, I have no idea–nor why there are no Fahrenheit numbers, just “1”, “2”, and “Very Hot”.

Our housemate, Alta, took the first bath after the water was done heating. We won’t need to set the dial any higher than 1 1/2; she reported that it was “very hot”; she definitely needed to mix it with cold. Beyond that, I went into the bathroom shortly after she got out, and whee-ew! The place was muggy! Steamy!

I’m hoping Pam doesn’t start lobbying for major bathroom ventilation now, but who knows? Her Honey Do list is endless.

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Product Review

So far, there are a lot of things I like about the A. O. Smith GDVT 50 101 propane hot water heater…and, with the extremely minor exception of the hard to read thermostat dial, nothing I don’t. The shipping dings were not nice, but they weren’t the manufacturer’s fault, either; the appliance had clearly been abused in transit. The burner is surprisingly quiet yet has an efficient sound to it, and the hot water produced is…hot.

That said, I’m giving the unit a full FIVE STARS.

There is, however, one final observation that needs to be made. The manual says you can install this tank in a closet…but don’t do it. The heat rising from the outer “cold air” flex piping–radiating upward from the inner exhaust piping when it bends from vertical to horizontal–is plentiful. In fact, that heat alone warmed the interior of the shed from 52 degrees to 70 degrees during its one hour burn. If that was installed in a closet, the temperature in there would be scary.

Which makes me believe I called it right when I decided not to install a ceiling in that back porch addition. Yay, me.

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