For questions generally relating to the hot-water supply system of a typical residential or commercial building, primarily regarding the heating mechanism itself (a traditional hot water heater tank, tankless heaters including "point-of-use", boilers and heat exchangers, etc).

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552 views

Sizing DHW expansion tank for tankless heater

I have a combined boiler for hydronic heating and DHW. Earlier in the winter, I started insulating as much of the pipes I can easily access. This has led to hot water coming out of the cold water ...
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1answer
435 views

How do I diagnose a hot water recirculation problem?

We have 2 ganged gas water heaters in a 10-year-old house. Professionals installed them last year to replace the 10-year-old pair. I'm pretty sure they are hooked up to a recirculating pump. This ...
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1answer
60 views

Water tank and timer (UK)

We recently moved into a small flat in the UK. For hot water we have an electric water tank with a main switch and electric timer: I made the following experiments: Main switch on / Timer on – ...
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0answers
28 views

Why is the gas water heater pressure valve leaking after installing recirculation pump & old radiator?

Kind of a complex situation. Using gas water heater as a boiler for an old cast iron radiator. In addition we added a recirculation pump. Everything was working fine but then we had leaking from water ...
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0answers
91 views

I've noticed the water from the sink won't heat up, while the water in both bathrooms heats fine.

I've been renting this home for more than a year and there have been a lot of plumbing issues - mostly leaks, but the water in the kitchen has always heated fine. There is a leak under the sink as ...
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1answer
191 views

Replacing water heater gas control valve

First let me summarize my questions, then provide detail: Summary: Can a newer gas control valve be installed on an older water heater? As an individual who has never attempted something like this ...
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1answer
134 views

How to prevent pressure from dropping from my water heater?

Until two weeks ago, my parents house used one water heater ( noted "1" on the picture) to provide two bathrooms and the kitchen with hot water. The bathroom on the first floor consists of a bathtub ...
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0answers
102 views

Can a water heater be installed overhead?

Sorry for the long preamble: I'm doing a remodel which involves building a new attached garage. At the same time, I'm replacing the water heater because it is ancient. I have considered a ...
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2answers
541 views

Why isn't the water on my second story getting as hot as I'd like?

I purchased a new whirlpool water heater about 2 months ago. I have a two story house, their seems to be a good hot water to the first floor faucets but it seems like it takes a long time for the hot ...
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1answer
335 views

Tankless water heater and inconsistent water temperature

We recently brought a house that was built in 1927, and much of it has been updated. The previous owners put in a tankless water heater two years ago. Our hot water is very inconsistent. When someone ...
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0answers
119 views

What would cause a water pressure drop after tripping a breaker?

I recently plugged my laptop into a cheap powerbar, which caused said-powerbar to short. This tripped the "sockets" circuit on the breaker, which, upon resetting, caused power to begin flowing to ...
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1answer
362 views

How should I avoid corrosion at this water heater connection?

I installed a new water heater 2-3 years ago. I put 3/4 pipe to PEX adapters on it and then used pex to connect to my house. On the hot water outlet, corrosion and rust is forming. I bought some ...
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0answers
92 views

Why am I not getting hot water from my tankless hot water heater?

I just bought my house last year. The previous owner had just replaced the boiler before I closed. I had oil delivered the day that I moved in. I had problems with the hot water right away as it ...
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0answers
805 views

What dangers are associated with changing the pilot light assembly on a gas water heater?

My A O Smith ProMax gas water heater started going out at various intervals. I would re-light it and it might stay lit for a few minutes, few hours, or even a day or so. I figured it was the ...
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0answers
124 views

Without having a pressure regulator or gauge, how would we determine what psi to set our new expansion tank to?

Without having a pressure regulator or gauge, how would we determine what psi to set our new expansion tank to? We just replaced the tank and hot water heater.Before replacing them, had an ok amount ...
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2answers
120 views

Using PEX for a water heating system

I am replacing my existing faucet plumbing with red / blue PEX all over the house. Everything that goes to the sink, dishwasher, washer, bathroom sink and so on will be color coded and installed ...
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1answer
371 views

Can I repair the floor in the water heater closet with an old street sign?

Can I use an old aluminum road sign as a replacement floor for my hot water heater closet? The old floor is rotten and has some give to it right where a portion of my hot water heater sits, and my dad ...
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1answer
1k views

Why did my hot water stop?

I have a Rinnai RL94 tankless water heater. Today something went wrong and now I have no more hot water. The machine is not showing any kind of error code like it has in the past when things went ...
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1answer
53 views

Bench soldering copper pipe into a subassembly

Is it possible to pre-assemble and pre-solder copper pipes into a subassembly that then can be installed using a threaded fitting? I'd much rather solder the joints either in an oven environment or ...
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1answer
49 views

Why the huge difference in cost for Tankless vs Traditional Tank water heater installation?

I recently had my 50 gallon traditional tank natural gas water heater fail on me. It cracked and flooded my garage. After the cleanup I called out my go to plumbing company to come give me an estimate ...
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1answer
84 views

Hot water running out, already replaced both heating elements and both thermostats

Our hot water runs out during one not-too-long shower. By the end of the shower, I have the cold water completely off and the hot water coming out is only lukewarm. My husband already replaced both ...
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1answer
41 views

PVC vent pipes or concentric vent pipes for tankless gas water heater?

I am trying to select a natural gas water heater to install into my house. It has to service two bathrooms with showers and two kitchen sinks, a dishwasher, and a washing machine. I've narrowed my ...
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2answers
99 views

Addressing irregular water pressure

Some time ago I posted about issues with my tankless water heater, concerned about the water going cold mid shower. Recently I found the issue isn't in the water heater - there are times when all ...
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2answers
138 views

Why can't I get hot water quickly at my vanity sink?

Whenever I turn on the hot water, it takes 3-4 min to get hot water at the vanity. It takes 1-2 min. for the shower. I have a gas heater. Can it be fixed or does it need to be replaced?
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2answers
1k views

How should a water heater drain pan be installed on a concrete slab floor?

My water heater sits on a concrete slab floor in my utility room next to a wall with a bathtub drain, and a few feet over from my washing machine drain. When I replace the heater I would like to ...
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3answers
136 views

How to determine gas leak on a water heater?

My gas water heater is certainly leaking gas. I can smell it. Using the image below, it seems like it might be coming from the red circle where the dial connects to the thermostat or the blue circle ...
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1answer
387 views

Is this electric water heater wiring correct?

I recently re-wired my water heater from 120v to 240v. I'm not sure why it was wired with 120v to begin with, but it was not providing enough volume of hot water. I looked up basic thermostat wiring ...
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3answers
333 views

Is it safe to install this hot water tank from ebay?

Is it safe for me to replace my electric hot water tank with this continuous electric unit that I bought on ebay? (I'm in Australia) Technical Specifications rated power 6.0KW ...
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2answers
5k views

What could cause a shower to give warm water for a few seconds, then only cold water?

The house has four bedrooms. The 40 gallon gas water heater is about 60 feet from this shower. The house is a one story house in flat terrain. I have already changed the mixing faucet for the shower, ...
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1answer
47 views

Water heater refuses to light after power outage

I have an AO Smith FPSH 40 252 High-Efficiency gas water heater, about 14 years old. Today we had a power outage due to high winds and when the power came back on, the heater refuses to ignite. The ...
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1answer
68 views

Low hot water pressure in one fixture after water heater replacement

I just had my water heater replaced (by a professional) and everything is great except the bathtub fixtures (shower head and tub faucet) in just one bathroom. The water pressure is really low, ...
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1answer
25 views

Rust in gas flame area of water heater, should be replaced?

There is rust right above the gas flame in our water heater (not outside the water heater as in this question Rust spots on water heater -- time to replace? or on the inside where the sacrificial ...
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1answer
42 views

What could cause my electric water heater to over heat water?

About a year ago our 15 year old electric water heater heated the water nearly to the boiling point until the breaker on the tank shut off the power. When I reset the breaker the temperature went ...
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1answer
116 views

Can I add elbows to move a b-vent exhaust?

I am planning out a kitchen remodel, and would like to move the main exhaust vent for the water heater about 4-6 inches from where it currently passes through the kitchen area. The catch is that I ...
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1answer
27 views

Are large temperature variation in a water heater normal?

I live in an apartment with a water tank and heater in the laundry room. About a month ago I had the heater replaced because it was leaking on my floor. Right after it was installed I noticed the ...
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1answer
602 views

Newly installed water heater with faint gas smell

Installed a new water heater last night (Rheem Performance Plus Model #XG50T09HE40U0). All went well with installation (including gas line bubble test), but this morning I could detect a faint smell ...
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1answer
120 views

Would connecting the downpipe to a gas boiler inlet save energy?

I have a condensing gas boiler for tap-water and central heating. Not very far from the inlet there is a downpipe outlet for the sewer. Since this smelly pipe is partially filled with the same ...
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2answers
770 views

What could be causing water to drip from the relief valve of my new gas water heater, again?

I installed a brand new water heater about 4 months ago, noticed that that relief valve was dripping like crazy. Checked the expansion tank and it was filled with water. I replaced it with a brand ...
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1answer
116 views

Why does my hot water smell like wood smoke?

We live in MN, in a house built in 2008 (and our water heater, installed in the basement, is about that vintage). For the past few weeks, I'm detecting a smoky smell from the hot water out of a ...
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1answer
694 views

Why is my water expansion tank leaking?

I live in the northeastern US and we just turned the heat on (oil) and this morning I went down to the basement and saw this: The water is coming from the plumping above something labeled "water ...
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1answer
45 views

How to measure water pump pressure in a spa heating system?

Short version (TL;DR): how can I measure the output pressure of a water pump in a spa heating system and verify that it is within the gas heater input pressure specs? The Whole Story I'm trying to ...
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1answer
37 views

Will a water heater use more or less power overall if equipped with larger or smaller heating elements?

For electric water heaters that can be obtained with various different options for the size and power draw of their heating elements, will larger elements use more power overall? For example, let's ...
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1answer
39 views

Should I unplug the timer on the water heater when shutting off water to the house?

If I shut the water off to the house, do I need to unplug the timer on the cold water heater?
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1answer
153 views

Running computers in basement storage room safely

I have kinda an odd one. I'm mostly concerned about fire safety here and am not concerned about power, I already know how to handle that properly. I have a somewhat large basement with an unfinished ...
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2answers
81 views

Hot water heating system: Renew or replace?

Our home was built around 1963 and has Gas powered Hot water based heating, some portion of the house is floor heated and some with radiators emitting heat from hot water. The heater may be 10-12 ...
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1answer
52 views

Why is there no hot water in the kitchen after flushing our water heater?

My husband and I recently moved into a new house that has two water heaters. One is gas and supplies the main portion of the house, the second is electric and (as far as we can tell) only supplies the ...
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1answer
133 views

How close can an electric water heater and an electric furnace be to each other?

How close can an electric water heater and an electric furnace be to each other? My water heater is 7 inches from my furnace. I need 4 inches so that I can install a water softener and wash sink. So ...
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1answer
594 views

Desuperheater vs Heat Pump Water Heater

I'm having a geothermal heating system installed in my home, and the contractor recommended heating my water using a buffer tank and desuperheater, which is a device that cools the refrigerant lines ...
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2answers
175 views

How much distance do I need to branch from water heater?

I moved my washer and dryer next to my electric water heater. I would like to know how close to the tank can I branch the hot and cold water lines. I would like to use a 3/4 to 1/2 inch reducer at the ...
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1answer
227 views

Water heater leaking from the top?

I recently noticed that water is pooling on the top of my water heater. When I took a closer look it appears that the leak is coming from where a metal hose comes into the top of the water heater. ...