Tankless hot water heater
 

Just curious if any of you have experience with tankless hot water heaters?

Looking at putting in a direct vent condensing model so that it will exhaust with pvc out the side of my house rather than up through the roof. We added a bedroom in the basement and the flue runs through the room. I think it will save a little money in the long run too, but thats not the most important reason for us.

My heat and ac unit already exhaust out the side and this would go in that same room.

As I read installation instructions it tells how to much natural gas in needs so now I am wondering if a larger pipe/meter will need to be installed.

I have also been told that you need to have a water softener to keep it from scaling and clogging.

Any input? I try to do as many things as I can myself, but may do the water softener and new water lines myself and leave the install of the water heater to a pro.





Randy





Randy

You need at least a 3/4" gas line depending on how far from the meter your heater will be. Those heaters are hungry when running. As far as a softener, it all depends on if you have hard water or not. The other option is about half the price is to get a direct vent hot water tank style. It vents out with pvc as well. Just depends your preference. I personally don't care for the tankless. They require a hot water valve to be fully open for it to kick on, and there is a delay before you get hot water. Also, you have to be really careful picking one out because to get the water as hot as you may want, means they decrease the water pressure. Another issue for instance, we just replaced our kitchen faucet. No matter what you remove in that faucet, it's low flow. Our hot water tank heater is less than 10 feet away, and it takes forever to get hot water to that faucet. I can actually get hot water faster to the upstairs sink that isn't low flow and has probably over 50' of pipe the water has to run through. That issue would be even worse with a tankless.

I put a propane one in 5 years ago and love it. I think mine is rated at 9.5 GPM and you will never run out of hot water. I went into the extended menu on mine and cranked the sucker up super hot.

I think it may take a little longer to get the hot water to the faucet but who cares, water is cheap.

Mine is a Rheem/Ruud 80% unit that uses a metal vent. I wish I would have picked up the 90+ model but my plumbing sales guy talked me out of it...probably because he didn't have one. I had to run 3/4 pipe to mine also. You can also get one that mounts on the outside of your house and don't have to do any venting. My stove is also propane and I have to fill my 125 gallon tank about 2 times per year at about $150 each time.

I have had no issues out of mine and only cleaned it one time since I installed it. I pumped vinegar through it for about 1 hour with the heater turned off.

When I go out of town I turn the propane off to mine (and the water to the house). I don't what would happed if you had a hot water line rupture and that thing pumped out 150*-160* water all day long.

I put a tankless in the last house I had. I'd do it again in a minute. All the issues people complain about can be solves easily. (Like low flow. That's just the end on the faucet, so change it out.) We have hard city water, and I never had to clean it in at least the 8 years or so I lived in the house with it. (It's still in the house I know because my ex wife lives there. :BlahBlah:) They are fantastic. But, yes, they are gas hungry. I did have gas pressure issues at the house after installing it, but ONLY when the furnace in the house, water heater and the furnace in the garage were all running at the same time. I had to learn to shut off the furnace in the garage before I got in the shower or it would really cool off. :biggrin2: I needed a larger meter/regulator. I had run large enough pipe, but the regulator wouldn't flow enough to keep up. My local gas company would have to switch it out. Don't let the gas company con you though, they will try to tell you that you have to go to a "commercial" meter. You tell them that's a crock of sh!t! Residential is residential, they just have to give you a larger regulator or meter. BTDT before.

Thanks for the posts guys!

I think from what I am hearing I will be OK. I have 1" gas line coming in the house and only have the furnace and hot water heater, so I may be ok there as long as the meter can keep up.

The one I am probably going to get is a Richmond/Rheem 9.5 gph and I really don't have a big house.

I live in a 1920 house and all the electrical had been replaced before we moved in but still had original plumbing. I have replaced about a 1/3 of my pipes with pex and will replace all of it when I do this. It will be nice to have all new pipes with water softener and filter. Just want to make sure this hot water heater is done right and will probably do everything but the hooking up the unit and venting it myself. Just a little nervous and want to make sure its right!


Thanks again and if anyone has more to offer, please do!




Randy

So if you are replacing with pex, are you running to a manifold or with the home runs? What size pex are you using? It's all going to make a difference in how your tankless performs. 1/2" pex is only going to get about 2.5gpm flow. 3/4" pex could get you about 4.5gpm.

As far as the low flow, it's not just a nozzle on the end of the faucet for kitchen faucets with the pull down nozzle. They have a small diameter hose that is used on the pull down part, and it severely restricts the flow. Nothing you can do about it. It's easy to check. Turn on the faucet full and fill a gallon container and time it to see how many gallons per minute flow you get. The biggest flow will be from the bathtub faucets, those would be 4gpm+. The pull down kitchen faucet you will be lucky to get 1.5-2.0gpm. Which means twice as long to get hot water. Then you need to check the specs of your tankless to see how many gpm of flow it takes to activate the burners and make sure your lowest flow faucet in the house is enough to turn the burners on. The shower heads are the lowest flow usually, unless you take the restrictors off.

You a plumber taylorjm?

In my younger days. Spent 10 years as a plumber/pipefitter until I started to see how bad it wore my dad's joints out and decided I didn't want to do it for the rest of my life.

The other thing you mentioned is that you are looking at a model that vents out through pvc pipe. Be aware, by using a power vent model like that is going to cause you even more of a delay before getting hot water. When you turn on a faucet, the flow sensor calls for hot water, but first, an exhaust blower has to turn on and ramp up, then a vacuum switch has to activate to show there's enough exhaust flow, then the burners light, then water can be heated.

What's the reason you are looking at a tankless? Is it because you want to take a 5 hour shower? Someone takes a lot of baths in a huge tub? Or is it because it will save money?

Taylorjim, I plan to do 3/4 to a manifold with 3/4 to the hot water heater. 1/2 out to everything else.

One of the big reasons for the tankless and direct vent is to gain some room where the hot water heater is and eliminate the flue pipe running through a bedroom I built in the basement. We are going to add a half bathroom in the room that houses the heat/ac and hot water heater. I live in a old small house.

But, I do want to make sure I do everything right.


Randy