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

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13
votes
4answers
3k views

Can tankless & conventional water heaters join forces?

Although I have properly maintained my nearly 20-year-old 40-gallon (150-L) Kenmore natural gas-fired water heater, I have been considering replacing it with a natural gas-fired tankless water heater ...
13
votes
5answers
941 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
4k 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
9answers
9k 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 ...
8
votes
1answer
332 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
1k 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
2answers
1k 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 ...
4
votes
1answer
2k 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
1answer
642 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
3answers
2k views

Chemical Smell After Tankless Water Heater Install

I recently had a plumbing company install a tankless water heater in my crawlspace. Everything with the install works and looks great, but we are experiencing a very strong chemical smell (like nail-...
3
votes
1answer
140 views

Installing a tankless water heater next to electric service panel

I am in the process of installing an outdoor natural gas tankless water heater. The issue I'm running into is clearances around the heater. There's a small spot on the back wall of the house where I'd ...
3
votes
0answers
530 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
1k 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
349 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
1k 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
2answers
356 views

Why would turning on/off hot water when the toilet is flushing cause the tankless pressure relief valve to release water?

I noticed the other day that my tankless hot water tank was occasionally spraying water all over the place from the Pressure Relief Valve. The only way I've found that seems to reliably trigger this ...
2
votes
2answers
60 views

warm water only when we replaced the hot water heater with a tankless heater

We replaced the hot water heater with a tankless version. We now only get warm water from the faucets and showers even though the temperature is set at 140 0F on the heater and the outlet pipe from ...
2
votes
1answer
565 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
980 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
82 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
1k 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
10k 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
1answer
541 views

Battery backup system for tankless gas water heater (outdoor install)

I have a Takagi T-K3-SP tankless gas water heater, which is installed outdoors. It still needs electricity though, so when I lose power at home, there's no hot water. The manual states it uses 86W ...
2
votes
1answer
231 views

Can I connect a tankless water heater with 3/4“ connections to my 1/2” plumbing?

I have 1/2" pipes from the water meter throughout the house with two full baths. Every fixture installed is fed by 1/2" line and doesn't have pressure problems. Soon I will need to replace my hot ...
2
votes
2answers
9k 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
56 views

Can tankless water heaters be mounted to the underside of joists in a crawlspace?

My single-story 1100 sqft home (1 bathroom + laundry + kitchen) currently has a gas 40gal tank water heater. We're looking to renovate and remove the tank water heater. It would be replaced with ...
1
vote
2answers
109 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
74 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
2k 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
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2answers
2k 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
3answers
1k 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
1answer
70 views

What is this “on” cap that's adjacent to my tankless water heater's service valve?

There's a "cap" next to my water heater's service valve that says "on" with an arrow. What is this "cap" and its purpose?
1
vote
1answer
56 views

I12 eccotemp tankless water heater

I am getting ready to install an Eco temp i12 tankless water heater. From what I have heard there is a possibility of cold air backdrafting through the direct vent and into the water heater, thus ...
1
vote
2answers
298 views

How to make a flushometer toilet look nicer?

I'm the new owner of a 3 bed, 2 bath condo in Chicago, built in 1923. It's lovely and old. Both toilets are flushometer style, tankless. They look exactly like a toilet you'd see in a public school (...
1
vote
2answers
3k 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
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1answer
63 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
5answers
3k 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
2answers
158 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
874 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

Protecting PEX Outdoors

I am installing a tankless water heater, which is an outdoor model. We are likely to use PEX when redoing the plumbing, but because the heater is outdoors, we will need to have a short, outdoor PEX ...
1
vote
1answer
3k 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
250 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
2answers
224 views

Why am I getting hum and lights dimming with a new electric tankless water heater?

So, I just installed an electric water heater and I'm getting a light hum from the water heater and the breaker panel. It's also dimming some lights.. unevenly. It seems to be more noticeable when the ...
1
vote
1answer
289 views

Water heater noises when my neighbor's sprinklers are active

Hello I recently (few months ago) installed a tankless water heater following a failure of the old 55gal gas heater. Performance has been fantastic, it actually resolved a number of problems, but I ...
1
vote
1answer
75 views

tankless water heater with four lugs

I'm replacing a old tankless with a new one. The old one is wired with 240 on two 60 amp breakers. It had two lug connects along with a ground. The new heater is 4 lugs and requires two 60 amp ...
1
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1answer
1k 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
54 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
1answer
3k 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 ...