Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [tankless]

A tankless water heater directly heats water on demand, instead of maintaining a reservoir of hot water. Use this tag in conjunction with the [water-heater] tag

12
votes
5answers
820 views

Installed Electric Tankless Water Heater - Internet loss when active

I installed an Ecosmart 27kw tankless water heater yesterday and as far as heating the water goes, everything works perfectly. The issue is when the water heater is running, I lose internet! Specs: ...
9
votes
4answers
2k views

Want to switch to tankless, but can I use my existing wiring?

The tankless water heaters I am looking at require 8 AWG wire but the existing wiring is 12 AWG. Can I do this without having to rerun new wire?
8
votes
1answer
304 views

How to evaluate the suitability of an electric tankless water-heater

I'm trying to evaluate if an electric tankless water-heater would be suitable for my home. There are just too many variables to consider, and I wonder if there is a mathematical approach to it. I'm ...
8
votes
4answers
190 views

Can my home's power supply handle this tankless water heater?

So my home was built in 1960 and 15-20 years later another room was added on. There are panel boxes everywhere ha. I have mapped it all out and isolated almost everything. Anything that is ...
7
votes
8answers
7k views

Prewarming for tankless waterheater

I have a tankless water heater that is just a little bit to small for our new house - the temperature rise isn't quite enough for the winter months. Our basement is big and relatively warm so I struck ...
7
votes
2answers
791 views

When do tankless water heaters need to be descaled?

I had a Bosch tankless natural gas water heater that stopped working with C7 and EA error codes and the plumber indicated that the unit had failed due to water getting into the internals like the fan ...
6
votes
1answer
2k views

How to determine tankless water heater requirements?

I'm considering replacing my insufficient 30 gallon gas water heater with a tankless water heater equivalent to 50 gallon gas heater. I know a 50 gallon heater would serve my needs. Questions ...
3
votes
1answer
107 views

Derating 6 current-carrying conductors?

I'm having a hard time understanding 310.15(B)(2)(a). Here's the boat I'm in: I hooking up a tankless water heater that calls for 3 40 amp breakers (it's a 24 kw Ecosmart). So I put in a sub panel in ...
3
votes
1answer
1k views

How could a hot-cold plumbing crossover spontaneously appear?

OK, this is a weird one. Follow the bouncing ball: I have a tankless water heater I've had problems the last few weeks with the water running lukewarm instead of hot. Someone suggested power-cycling ...
3
votes
0answers
290 views

Tankless 240V water heater in detached garage tripping AFCI/GFCI breakers in house

We have two separate buildings, a house and a garage/workshop, about 20 feet apart, sharing the same electrical service. On the service entrance, there's a Siemens whole-house surge protector. The ...
3
votes
1answer
830 views

Tankless water heater requirements

I'm looking at the possibilities of replacing my water heater. Currently we have an electric, 2 element, 50 gallon tank heater that is 32 years old and almost ready to go. The water can sometimes come ...
2
votes
2answers
263 views

16“ center bracket to 24” center framing

I'm installing a tankless water heater (150lbs static load, 10" deep) I only have one option for installation and it is a 2x3 framed wall with 24" centers. The Top bracket is designed to mount on ...
2
votes
4answers
909 views

Electric Water Heaters: Tank vs Tankless (Instant On) Energy Usage?

I've been told that a tankless electric water heater is enormously more expensive than a tank water. I have a 50 gallon water heater that I must replace. I have a friend who is a plumber telling me ...
2
votes
1answer
42 views

Tankless water heater and shutting off main water supply

I have a tankless water heater, love it! And it's not the issue. I have a very leaky shower. I've been in my house for almost 20 years and for the first 10, I didn't mind the very slow drip since my ...
2
votes
2answers
112 views

Will a 2 PSI natural gas line be sufficient for a tankless water heater?

I'm planning on installing a tankless water heater that maxes at 160K Btu. I only have a 1/2" line from the meter to the furnace(75K) in the same room. The city told me that there is 2lb gas from ...
2
votes
1answer
80 views

Residentail Tankless Water Heater Electrical Concerns

So the electrical install guide for Ecosmart ECO 18 requires 2 (two) 40 amp double pole circuits. They specifically mention running two grounds too which I gather would be provided if NM cable w/...
2
votes
3answers
712 views

Can tankless water heaters be used in Europe?

I just discovered tankless water heater technology while browsing alternatives to gas based water heating, more specifically the ones designed in the United States by EcoSmart. I have been trying to ...
2
votes
2answers
8k views

What could cause my tankless water heater to make a knocking sound?

I recently replaced my water heater with a tankless unit (Rheem). After installation I noticed that whenever I turned on the hot water; or when my central heating unit would turn on, the tankless unit ...
2
votes
2answers
8k views

What size breaker and wire do I need to feed a panel for a tankless water heater?

I purchased a electric tankless water heater and I would like to know the following? The unit requires 3 separate 40 amp breakers, one for each line. I have 200 amp service. The subpanel will be ...
2
votes
0answers
463 views

Chemical Smell After Tankless HWH Install

I recently had a plumbing company install a tankless hot water heater in my crawlspace. Everything with the install works and looks great, but we are experiencing a very strong chemical smell (like ...
1
vote
2answers
101 views

Should I replace my conventional interior water heater with an exterior tankless model?

I'm shopping for a tankless water heater. When the salesman talked to me, he told me they install them outside and this is better because then the tanks do not take up room inside the house. I'm ...
1
vote
3answers
60 views

Is a tank less water heater a bad choice for a house with low water flow?

We are thinking of replacing our current natural gas tank water heater by a high efficiency tank less heater. However we have a water main issue, the house is from 1930 and the main is partially ...
1
vote
2answers
161 views

help determining amp service to my house

I'm considering installing an electric tankless water heater in my house, but need to know what amp service I currently have. I read that you should look at the amps on the main breaker to the house ...
1
vote
2answers
80 views

Tankless Water Heater and turning off main water supply

I presume there must be plenty of protections for such a case, but is there any reason to be concerned if I turn off (or my fortrezz value and smartthings turns off) my main water supply and my Rinnai ...
1
vote
1answer
60 views

17 years old tankless, fix or replace?

I have a 17 years old conventional tankless combi boiler, it has a 'spilling' 3-way and DHW exchanger clogged by limestone. Should I fix it or I'd do better replacing the whole boiler with a new ...
1
vote
2answers
849 views

Can a tankless water heater outlet pressure be increased without a second heater?

My father-in-law has a five-bedroomed house with three bathrooms, two of which are in use. The household is gravity-fed with a cold water tank on the roof, and a gas-fired tankless water heater on the ...
1
vote
2answers
595 views

tankless water heater before the reg hot water

What if I installed a new tankless water heater before the regular hot water heater, so that the tank water heater is getting filled with hot/warm water vs the 40 degrees water its getting now? Our 80 ...
1
vote
2answers
105 views

What is this pipe beneath my tankless water heater?

While watching videos about draining tankless water heaters, I noticed none seem to have this beige pipe with odd silver cab at the end. Does anyone know what this is and its purpose?
1
vote
1answer
575 views

Wiring washer, dryer, tankless water heater

Trying to wire for washer/dryer combo in the garage, and we need to add a tankless water heater to get hot water to the washer. In their current location, there's a (EDIT: 15) AMP circuit for washer, ...
1
vote
1answer
2k views

What is the best way to mount a tankless water heater to a concrete wall?

I am planning to replace my hot water tank with a Noritz NRC98-DV tankless hot water heater. The best location to mount the new heater is in the basement on an outside concrete wall. The heater will ...
1
vote
2answers
202 views

Why do both water tanks have hot inputs? Is my boiler (on-demand) feeding into my hot water heater?

I have an interesting setup that I'm trying to understand (without tearing apart sheetrock). I have two electric tank-based water heaters, and a tankless gas water heater that is used for the boiler ...
1
vote
1answer
136 views

Tankless water heater plumbing: neutralized condensate and pressure relief valve

Hello recently my old 50gal gas water heater developed a crack and started leaking. I replaced it with a tank-less gas heater. Everything is good, I installed the proper intake an exhaust with 3in ...
1
vote
1answer
48 views

what is a reasonable amount of condensate water produced by my pump?

I have a Ruud hi-efficiency furnace and also a Ruud tankless hot water system, both with condensate lines running down to the pump. My problem is... the pump runs (intermittently) ALL day long..lol.. ...
1
vote
4answers
2k views

Buffer tank on input or output of tankless water heater?

As I understand it, in residential systems, tankless water heater are commonly paired with a buffer tank to deal with the "cold sandwich" and finite capacity of tankless heater1. This seems ...
1
vote
1answer
1k views

How to chlorinate a tankless water heater?

I live on a private well and have had a tank for a while. Every few months I'd have to chlorinate the tank (with hydrogen peroxide) to get rid of the rotten egg smell. Two local plumbing companies ...
1
vote
2answers
2k views

Pex Pipe Freezing & Tankless Hot Water Heater Too

I have Pex pipes. My issue is freezing pipes and tankless hot water heater on the north side of my house (built in 2009) where my master bath is (the tankless is on the outside of the house on that ...
1
vote
1answer
693 views

Tankless water heater - not consistent hot water output

I have a tankless with a descaler on the cold water input. When I turn on the hot water at the faucet it takes a minute or so to get hot water. Then I'll hear some banging/knocking of the pipes. ...
1
vote
1answer
272 views

Tankless heater that only works in the morning

We purchased a house with an existing tankless heater (installed in 2009). It would occasionally fail with error code 11 (no ignition). Over the past 2 months it has been failing more often and now ...
1
vote
1answer
92 views

Short run of propane to stove and tankless WH

I have a small stove with a propane conversion kit and a 3gpm propane tankless water heater. This is for a small MIL suite ~650 sqft. Both the stove and the water heater are on the same exterior wall, ...
1
vote
2answers
5k views

I Replaced Pressure Relief Valve on Rinnai water heater (twice!!). New one does not hold ANY pressure

I just finished replacing the pressure relief valve on my Rinnai hot water heater. Everything went well, I turned on the cold input and wham, water just started gushing out of the relief valve. All ...
1
vote
1answer
48 views

Need help with install for weil mclain oil boiler

I just bought a weil mclain oil boiler with tankless. Can anyone tell me the configuration to plumb it? I asked two heat guys how to plumb it and they gave me different setups. I plumbed it ...
1
vote
1answer
1k views

Which is better indirect or tankless hotwater heater

I am in the process of getting my boiler and hot water heater replaced. One company gave me a quote for a Weil McLain boiler and indirect hot water heater. Another company gave me a quote for a bosh ...
1
vote
2answers
395 views

Can I replace my oil-based water heater with several electric ones?

I was looking at this question, which is somewhat related to mine but didn't give me a good answer: How to evaluate the suitability of an electric tankless water-heater Basically, my mom's water ...
1
vote
0answers
40 views

unique ? about venting tankless water header

I am installing a tankless water heater at the house. My question is unique because I can not find a reference anywhere in the code and the installation manual about where to place my exhaust vent. I ...
1
vote
0answers
105 views

Furnace draft inducer switch tripping

I have an older furnace and a brand new natural gas instant water heater that I installed. I only start this way because the furnace had one thing break last year, so I'm not sure if things on it are ...
1
vote
0answers
53 views

Service needed to add a tankless water heater

I am currently building a detached 250 sq feet studio in my backyard. The studio will have a tiny bathroom with a tankless water heater, a baseboard heater, and a few lights, a mini split (ac), of ...
1
vote
0answers
518 views

When upgrading a gas meter, do you need to install/upgrade regulators for natural gas appliances?

I live in TX and have Amica as my natural gas provider. I want to replace my tank water heaters with a tankless unit. According to the Amica tech, I will need an upgraded gas meter which would ...
1
vote
0answers
116 views

Tankless water heater - Electric issue

I have a AuqaPower Tankless water heater I installed myself 2 years ago. I used the old wire from old (tank) water heater and I ran a new wire for the 2nd place. It has worked great for 2 years and ...
1
vote
2answers
787 views

T&P valve draining - expansion tank issues?

I am having issues with my Water Heater. It's a slantfin tankless boiler (TR-30 PT). It's running on a 4 zone setup. I typically only use one of the zones though. We've been in the home for a year and ...
1
vote
0answers
325 views

What type of air conditioner to look for

I'm looking for a portable air conditioner that can be moved from room to room. But the key thing I want is one that does not use a condensation tank. I know they exist because I have seen one. It ...