Before it dies, I'm getting a local plumbing place to quote swapping out my 22-year old 50 gal gas State unit with a 75-gal gas unit. They're recommending an AO Smith unit that comes with a 6-year warranty and, if I pay another $250 to have them install an expansion tank in the cold water line, the plumbing place will cover any labor costs for the same period of the manufacturer's warranty on the tank. Given how old my present unit is, I'm not sure how necessary the expansion tank really is; could be more of a payment to cover the labor warranty.

Any comments or concerns about this? AO Smith ok? Both the old and replacement units are standard atmospheric vented units - no high efficiency motor-driven exhaust or anything like that. Thanks.

Any reason to not go tankless?

The top outfit locally, Oliver, charges about $2200 for a WH install. They put an expansion tank on every install. They also give a ten year parts and labor warranty. It's all included in the package.

People buy into the "never have to worry about it" and pay the extra $1,000.

If Oliver, the same company which does commercial sprinklers, thinks the expansion tank is good for the WH tank (and ultimately, their warranty), there is probably some basis in that.

Another chapter from "Never too old to learn" ... I did some googling and found this:

A few things that can extend your water heater's life: Install an Expansion Tank: When water is heated from 50º to 120º, it expands. ... This expanding and contracting causes stress on both your water heater and your plumbing system which can cause damage and even premature failure. May 3, 2013

Extend Water Heater Life with Simple ... - Carter's My Plumber
https://www.cartersmyplumber.c...d-water-heater-life/

A.O. Smith has been around forever. I still see ancient grain silos with that tag on them.

quote:

Originally posted by Gustofer:
Any reason to not go tankless?

Couple reasons. A single tankless for the entire house would likely be as much or more than a tank, and it appears most of them require special venting which means my existing roof vent wouldn't work for it (read that as added $). I'm not sure but it also might require a bigger gas line than presently runs to the water heater's location ($ again). If I'm lucky enough to get another 22 years of service from a replacement, I probably won't be worrying about what happens after that!

I'd get a quote(s) on a Rinnai tankless. Cheap to run, never run out of hot water, and it lasts for a LONG time. If you can put it on an outside wall the venting is not a big deal or costly. I sure wouldn't avoid it just to utilize a vent pipe.

quote:

Originally posted by Woodman:
When water is heated from 50º to 120º, it expands. ...

Well duh... BUT, unless you have a check valve or similar acting part, like a pressure reducer valve, in your system it is physically impossible for the pressure to rise in your heater or your plumbing. You can not magically have more pressure built up in your pipes than the incoming pressure from the street. The expanding water simply backs back out to the street and the pressure remains balanced with the water supply.

Now most don't, but I DO have a check valve, and after taking a long shower the pressure in my plumbing, if no water is used anywhere to relieve the pressure, will rise from 30 PSI to ~40. I have a pressure gauge installed permanently near my washing machine to monitor my incoming pressure, the law here requires that the water supply be a minimum of 20 PSI. Mine sometimes gets close but never under that. I wish it would! The utility would be required to upgrade the system to comply. There is a booster pump within 1/4 mile of me on the main line... before the next house, just missed me here. dang it!

All that aside, IIRC water heaters are pressure tested to 300 PSI and rated for 150 PSI operating pressure. At least they were when I was plumbing... I don't see in normal use getting anywhere near that.

quote:

Originally posted by tsmccull:

quote:

Originally posted by Gustofer:
Any reason to not go tankless?

Couple reasons. A single tankless for the entire house would likely be as much or more than a tank, and it appears most of them require special venting which means my existing roof vent wouldn't work for it (read that as added $). I'm not sure but it also might require a bigger gas line than presently runs to the water heater's location ($ again). If I'm lucky enough to get another 22 years of service from a replacement, I probably won't be worrying about what happens after that!

Not trying to talk you into anything you don't want to do, but I bought the heater and the parts from Amazon and had everything installed by a master plumber, including running a new gas line from under the house and putting in the vent on an outside wall. Grand total? $1200, and it's already almost paid for itself in propane savings.

Just a silly question, but 75 gallons? The newer heaters heat quickly enough that a 40 gal doesn't tun out of hot water. I stepped down from a 50, save money and got a 15 dollar a month cut on the gas bill. But you know what you need, I don't.

quote:

Originally posted by tsmccull:

quote:

Originally posted by Gustofer:
Any reason to not go tankless?

Couple reasons. A single tankless for the entire house would likely be as much or more than a tank, and it appears most of them require special venting which means my existing roof vent wouldn't work for it (read that as added $). I'm not sure but it also might require a bigger gas line than presently runs to the water heater's location ($ again). If I'm lucky enough to get another 22 years of service from a replacement, I probably won't be worrying about what happens after that!

Not sure where you're located. But here in Florida they put a Rinnei tankless water heater outside on the exterior wall opposite of where the old water heater used to be and tie right into the plumbing if there's a convienent place right on the outside of the house where your old one was inside. It needs no venting ductwork or anything.

I'm just trying to figure out why going to a 75 gallon. Honestly a new 55 gallon is probably fine. My guess is your 20 year old water heater is only heating/holding 30-35 gallons of water and the rest is sediment.

quote:

Originally posted by jimmy123x:

Not sure where you're located. But here in Florida they put a Rinnei tankless water heater outside on the exterior wall

I just put one in for my sister about a year ago here in Tennessee, with a recirculator, on the outside of her house. Had to do some re-plumbing to complete a circulating loop and insulate her pipes. It freezes here in winter so we added the optional automatic control and valves to drain the unit if the power goes off. As long as the power is on and working it won't freeze. She loves it so far especially the circulator and the instant hot water at every tap in the house. It freed up the space of the old one in her pantry. It was expensive though.

The extra volume is to better supply a hot tub on the opposite end of the house from the water heater. Even when new, the 50 gal took most of its capacity to fill and raise the tub's temp sufficiently and once the tub started cooling off, it doesn't recover fast enough to send more hot water to keep the tub hot. Pretty sure the builder didn't analyze it but just guessed. I figure those extra 25 gallons should solve the problem.

A big enough tankless would certainly work, but where I'd have to put it is a long way from any external wall.

I have apartments and have bought water heaters by the pallet in the past. I used to install AO Smith 100 series exclusively. About the time that the water heaters changed to comply with the new mandates (5 years ago or so?), I started getting a lot of failures with the AO Smiths. One had a ruptured tank, another a bad gas valve, and something else on another, can't remember. It seemed like a lot of Smiths were leaving the factory flawed. Talking with some of the handymen I use, they confirmed my suspicions that something was up with AO Smith. At least with the 100/101 series. Maybe they've worked it out by now.

I have since installed Bradford White heaters without issue, and have had some good luck with Rheem units. Not the Rheem units they sell down at the Home Depot, but the professional ones I get at a plumbing supply for the same cost, with brass drain valves.

Like cparktd mentioned, an expansion tank is only helpful if you have a check valve installed between your house and the city. Some cities are installing them on every house meter to protect themselves from a meth lab contaminating the city system. Even then, if pressure was a continuing problem, your TPR valve would indicate it by popping off after most cold water fills.

quote:

Originally posted by tsmccull:
and once the tub started cooling off, it doesn't recover fast enough to send more hot water to keep the tub hot

Ah, OK. I put a 110 volt inline heater in the pipe exiting the pump for my jacuzzi when I plumbed it, it automatically reheats the water and keeps the water warm as long as the pump is running. Works great.

Is your water actually hot, or just warm. Water Heaters used to come set on 155° from the factory. Then that got reduced to 145 and now even much lower. Some as low as 120 now. You might benefit by just turning up the temp a tad. Careful, especially if kids in the house. Just something to check, your old heater may already be set high enough. I keep mine about 145.

A.O. Smith is ok, but I prefer Bradford White.