Tankless Selections

[karoc]

Using the graph table at Supply House I’ve narrowed my choices down to two Rinnai. 1st is 120,000 but’s and 2rd is 140,000btu’s which there is about 2-300.00 different. Looking at their chart with my location being in Texas is saying ground water temp is 62-75* and desirable water temp 120* And my fixtures being bath/kitchen faucets, clothes washing, shower. Looking like I’m at about 5 gpm, which I believe puts me at 120,000 btu’s but I think that’s borderline. So I am looking also at 140,000 btu tankless. So is it better to go up size when it seems at max of 120k? Going give them call today for some confirmation on size, but wanted to run it by GJ for some input also. Thanks for opinions

 

[Sumboodie]

Mine is 190k BTU I believe and my input water is about 38*.

You sure your input water is that hot?

Bigger isn't too much an issue as it'll modulate. I've never had trouble but that's just with 1 fixture running (ie shower)

 

[nadogail]

It has been 55 years since I last owned a Tank Less water heater, for just my wife and I we never wanted for hot water. I was living in Spain at the time and I am sure the water heaters sold locally in the mid 60's were of lower capacity than the current models available in the US.

 

[mike93lx]

I'd go bigger.

Are you putting it outside? I always felt like that was weird, but it's probably just from growing up in new England.

My summer time water temp in VA can clear 70 degrees, but in the Winter, it's in the 50's. We use a tank heater, though

 

[karoc]

Thanks guys for responding, going by temperature chart for ground water in my location that is about right.
Talking with supplyhouse.com the lady suggested also as Mike saying to go little bigger just in case someone taking shower and clothes washing is being done and dishes are being wash at same time. While I value supply house.com’s input I also value y’all input who has the experience using Tankless. My first intent was mounting it inside, but looks like here in south mounted outside. Do get freezing temps but not for days. But I’m still going take precautions and insulate build cabinet around piping. Please keep inputs coming, not going place my order for couple days.

 

[shade]

I'd also go 190k.
I love my 190k Rinnai. Amazing unit.

 

[housewolf]

FWIW; I have the 199K BTU Rinnai NG model. Not saying you need that large but I’ve never caught myself saying, “Damn! I wish I had less hot water”

Build.com is owned by Ferguson Enterprises, probably the largest wholesale distributor for plumbing supplies in the US. (I am not affiliated in any way) It appears they have a better price on that WH. Two day Shipping is included in the cost.


ETA: make sure you get the valve kit with it for flushing. Also if installed indoors you’ll need a vent and pan for it too

 

[mike93lx]

If you can put it inside, I would. Especially as a retirement home, the last thing you need to be worrying about is a pipe bursting in a freeze

 

[wssix99]

You might research if there is a cleaning impact by oversizing. That would be the only thing that would hold me back from going up a size.

I would definitely install your unit inside. You will need to clean this thing yearly. Having it inside, with a proper drain accessible will make your life so much better.

Things I wish I knew before installing a tankless:
- The condensate that comes off these is acidic. You need a drain designed to take it.
- READ THE INSTRUCTIONS BEFORE INSTALLING. Then read them a second time. There are important little details. For example, you may need Schedule 80 non-foam core pipe to get the maximum performance out of your unit. (My plumber installed mine with foam-core Schedule 40 and I had to throttle mine down in the settings as a result.)
- Make sure your service ports are installed for easy access and cleaning.
- Figure out how you are going to get spare parts. (These things have hundreds of parts. When one breaks, you have no hot water. Can you get Rennai parts locally the same day? I have a Navien with no distributors in my area, so I have a full cabinet of spares for all the critical pumps and parts so I'm never without hot water.)
- Install a drain pan underneath! (Your unit will leak when parts go bad and this will also help during your annual service.)

 

[justsam]

Are you replacing a tank unit or a tankless unit? These units use a lot of fuel, for a short period of time. Make sure your propane delivery to it is capable. I use natural gas on an outdoor unit in Northern California, and after years of use realized PGE had vastly undersized the gas meter as the home has two gas fireplaces, gas heat, gas dryer, gas oven, gas cooktop, etc.

Make sure you have some form of recirculation and a pump for it if not internal to the unit. I have a separate recirc loop using a Grundfloss pump controlled by an Alexa command. It is true tankless can provide an "endless" supply of hot water,, but without some form of recirc you might wait a long time for it to get there.

As mentioned make sure you have some form of isolation valves so you can descale the unit. These may be built in. I have two Rianni units on two different homes and both have been in service for about 18 years with no issues.

There is a gentleman on here, I believe it is JACKFRE who helped me with tankless questions.

 

[karoc]

Wow, this is eye opener, thanks for heads-up housewolf. With that savings I can move up to 160k, since there is room to put it inside, then y’all talk me into it. I was just wanting take easy way, put peace of mind be worth extra work. Going shopping at Build.com

 

[karoc]

Justsam, I forgot say that this is new construction, clothes washer and kitchen sink will be only few feet away. The shower is about 32’ away, only 1000 sq ft living space. I don’t think it would be to much of wait for hot water. But trying to understand that return loop or that valve that go under bath sink. If I really need it or not. I figure keeping it simple means less parts and less problems to go wrong. I glad to know about drain pan now for putting tankless inside
I haven’t started on propane system yet, no lines been ran and no tank. I have propane guy but haven’t setup time for him to come out yet for suggestions, that be more questions on that at later date

 

[justsam]

I have an 850 sq ft guest house, and no recirc. on it and it is fine. It becomes an issue on larger homes.

 

[gleman]

I went electric after replacing my tank. It's been really hassle free since 2013. An Eco Smart. Really easy to service and descale once a year.

I did put a separate undersink unit in the kitchen because I didn't like the 30 second delay.

 

[karoc]

Sorry keep changing my mind, but good information does that when I really can confused. Here’s my new list, I could find the drain pan for tankless. May have to look elsewhere. My list:

 

[admranger]

If it were me I'd go with a heat pump water heater instead. I have the tankless and it's fine, but fuel prices this year were something I think we'll be seeing more of in the future. Heat pump water heaters qualify for a tax rebate unless you're a super high earner. They are more efficient and if you put solar on your house (tax credit), essentially free to run. Although, with the electric distribution situation in Texas being iffy for the time being, maybe this isn't my best idea.

 

[wssix99]

The shower is about 32’ away, only 1000 sq ft living space. I don’t think it would be to much of wait for hot water. But trying to understand that return loop or that valve that go under bath sink. If I really need it or not. I figure keeping it simple means less parts and less problems to go wrong.

If you are married and this goes wrong, its going to be your fault...

I would put in a recirculating line now. Its really inexpensive to do. If you don't need it, just turn off the valves for it. If you need it, add a recirculating pump and you are good to go. BTW - Don't forget to insulate the supply lines AND the return recirculating lines!

It's not the length of the run but the volume of water you need to move. Due to pressure needs for how our system is laid out, we have 1" lines that serve part of our house where there are a lot of sinks and showers. Even though my shower is less than 20' from the tankless, it still takes 4 minutes for the water to heat up and flow all the way through.

We have tried a number of timers, etc. on our recirculating pump. In the end, we have it plugged in to a smart outlet, which is great. We can set a timer so hot water is ready-to-go for busy times of day or we can go on an app and pre-heat the system if we are going to take showers at off times, etc.

 

[mike93lx]

If you are married and this goes wrong, its going to be your fault...

Oh come on, how bad could it be?





Said no married man, ever

 

[karoc]

Like my ole father inlaw would say” It’s better to have it than to want it”
Someone had sent me illustration of a recirculating line but can’t find it so going investigate that on how to install. I do have enough Pex to make that extra run. I never gave it thought to insulate those lines so thanks for that wssix99 Yes 4 mins is long wait

 

[mike93lx]

I can't imagine needing a recirc in a 1k ft house. I bet you'll turn off the pump after seeing the power and gas bills from running it.

 

[Notgrownup]

my Rinnai froze once but it was a ******* mistake By my plumber. Being from Canada I had no issues for it being outside but he put pipe insulation first then heat strips over the insulation… I was of course in Mexico on vacation when it froze . I asked my son-in-law law was the heat strips on he said yes I can feel them , then I asked him are they on the outside of the insulation, he said well yes they are…. I laughed.
go bigger and no recirculating pump unless you have a peak time timer. More **** to break.

 

[Steve W.]

When I installed my tankless (replacing a 50 gallon tank), I had different constraints to work around.

1. The house (built in 1957) is all 1/2" copper plumbing, so we are already used to the concept of "one faucet at a time". There are two of us there most of the time, three during the winter, so it's easy to let others know when showers will be taken, laundry done, dishwasher run, etc.

2. Wife came from a country house that was all-electric. You lose power, you lose EVERYTHING. Since we are on city water and natural gas, she still wanted hot water in the event of a power outage. Most pilotless systems use electric for ignition. No good. I told her that some use batteries. No good, just her luck, the batteries would be dead. Found a Bosch unit that uses a turbine in the water line to spark the ignition. Makes a whirring noise while running, but it's a reminder that someone is using hot water.

The bathrooms and kitchen are grouped right next to the utility closet and water heater, so hot water is available within 20 seconds. The laundry is farther away, but that is no problem.

After installation (about 15 years ago), we found that the gas bill went down, but the water bill went up for a few months. We were enjoying hot water for longer showers. When that novelty wore off, water usage went back to normal and the gas bill went down even more.

Only problem encountered was with a thermal safety switch that flaked out. Fixed that and have been enjoying hot water.

.

 

[Jackfre]

I represented Rinnai for 30 yrs. I’d go with the 160 indoor unit with the 2x4” concentric vent kit. If this is single story you can run the vent vertically thru the roof. You can also run Sch 40 pvc. DO NOT run a single pipe. you want a direct vent set-up with whatever you choose. If you are going re-circ buy one of the units (180 & 199)with the built in pump. Higher cost but if you need it don’t try adding circs and controls for re-circ. Before adding recirc, which really increases cost, as this is new construction consider placement of the unit. Do keep it close to the kitchen because that is where delay drives me nuts. Can you place it between. I have actually run 3/8” pex to a kitchen faucet. Delay in temp delivery is distance driven but also pipe size. 3/8=.11 sq In, 1/2=.19, 3/4=.44, 1”=.77. You have to watch out for pressure drop due to pipe length. Lack of care in piping causes more displeasure than about anything I have seen and I base this on all those years. Indoor/outdoor be aware that if you loose power you loose the freeze protection when you need it. I’ve seen people return home and find that someone wanted their water heater more than they did, apparently. Now, my 30 yrs with them ended 5 yrs ago and I have not followed all new developments with them. Rinnai is an excellent outfit and I really enjoyed representing them.

 

[karoc]

Thanks Jack for posting, could you look this over let me know what you think. It has a recirculating pump. Thanks for helping

 

[wssix99]

I can't imagine needing a recirc in a 1k ft house. I bet you'll turn off the pump after seeing the power and gas bills from running it.

The nice thing is that modern technology gives us choices. Even if one were to plug the pump into a smart outlet and only run it on demand, that's X more showers where one would save gallon$ from going down the drain before things get hot.

 

[mike93lx]

The nice thing is that modern technology gives us choices. Even if one were to plug the pump into a smart outlet and only run it on demand, that's X more showers where one would save gallon$ from going down the drain before things get hot.

I like options. In a small house that time to hot water will be very little, but it's just trading burning fuel to cut some water usage.

 

[Jackfre]

Early ‘01 or ‘02 I had a Rinnai customers water heater fail. It had been in for about 8 mos. That just does not happen on Rinnai’s. The factory wanted it back for testing so I picked it up. They put it on the test stand . Turns out the customer added a circ pump to the system, plugged it into the outlet and was happy as a clam. In 8 mos that unit saw according to flow standards approx, 48 yrs of typical flow and it cycled on/off 88,000 times. That kicked off the assorted, “how do we sensibly do recirc,” The best system is “on-demand” IMO. In my daughter’s rather large typical home I used the wireless control with a motion sensor in the bathrooms. So, as you entered the room the sensor over thedoor up in a corner made the circ and shut it off when it sensed warm return water. My experience is the kitchen is the place that drives people nuts waiting for hot water. For that a wireless push button was installed under the upper cabinet lip next to the sink. That worked well as long as you had solid wireless. Without it, it was a giant pita. I’ll check today to see what they are doing now. I know they have changed something on it but am not sure what.
In today’s world with drought etc common in areas I never thought it could be recirc does become more of an issue. Here in CA water saving is more important than energy saving.

 

[karoc]

Thanks Jack for responding, I don’t believe wireless will work for me. We have metal roof which cell phone signal is terrible, plus all trees. But I like the motion sensor idea with mounted in bathroom. Guessing there are connections in tankless for wiring?

 

[JOE.G]

I have a 199K Navien unit with Re-circ feature. I have had it since 2010 and did replace the heat ex-changer last year under warranty. I tried the Re-Circ feature which works great but I just don't believe it is needed and not worth the cost of purchasing and using. Water gets hot to all fixtures quickly except for one bathroom but even then it is not that long. Mine is mounted in a non heated part of my basement and the intake/exhaust pops right out of the wall with PVC.

 

[Mike65]

We had a tankless water heater installed when we were renovating our home 3 years ago. It is a Navien model #-NPE-210A, rated at 50GPM NG converted to LP that is vented out the back of the house with PVC pipe. It is installed on the exterior wall of the basement which is heated near where the old water heater was. The tankless water heater is located close to both of the bathrooms & the kitchen. It only takes about 15 - 20 seconds to get hot water to either of the 2 bathrooms or the kitchen.

Navien NPE-210A2 180,000 BTU Condensing Premium Gas Tankless Water Heater

Navien NPE-240A 199,000 BTU Condensing PremiumGas Tankless Water Heater.

www.mytanklesswaterheaterstore.com