Water heater inspection, diagnosis and repair questions & answers.

This article series gives in-depth articles on inspecting, testing, and repairing problems residential hot water heaters of all types, including their parts, controls, and alternative sources for hot water as well as tips for improving hot water temperature, hot water pressure, and hot water quantity. Page top sketch provided courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ].

Water Heater Inspection, Installation, Diagnosis, & Repair Questions & Answers

These questions & answers about cylinders, calorifiers, or hot water heaters were posted originally at WATER HEATERS - home - our master list of diagnostic and repair articles. That's a good place to start if you're having trouble with your calorifier or water heater system.

[Click to enlarge any image]

On 2022-02-15 by Inspectapedia Com Moderator (mod) - Building Code Citations for locations are water heaters prohibited

@PV,

Prohibited locations. Gas-fired water heaters use fuel combustion for heat.

For safety, do NOT install a water heater (calorifier, geyser, hot water cylinder) in bathrooms, clothes closets, rooms used for sleeping, or in any closet or confined space that opens into a bathroom or bedroom.

Exception: Direct vent water heater

Model and local building codes for water heaters are

at WATER HEATER SAFETY - web article, code citations, quotes

Here is one example: WATER HEATER INSTALLATION INFORMATION, Bulletin 293 [PDF] San Jose, CA. water heater code.

See more water heater codes found in model or adopted

PLUMBING CODES

On 2022-02-14 by PV

@Inspectapedia Com Moderator, Do you know if this is a building code reference or gas code by chance?

On 2022-02-14 8 by Inspectapedia Com Moderator (mod) - can I install a gas-fired water heater in a bedroom closet?

@PV,

No.

On 2022-02-14 by PV

Are Gas water heaters permitted in bedroom closets? Just wondering aloud regarding potential for gas leaks or exhaust concerns?

On 2018-03-09 by (mod) - landlord moved water heater outside

Fran,

More likely the water heater will stop working from rain, rust, corrosion, or freezing. It may also be unsafe.

On 2018-03-08 by Fran

My landlord moved the hot water tank from the attic to make room for a heating and air unit now the hot water tank is outside will this cause the hot water tank to excessively heat to water in the winter time

On 2017-09-24 by Sandra

A 40 gallon electric hot water heater was tested at 2 AM and took 3 minutes to reach 143. No water source was used for the previous 8 hours. Would it take the same amount of time to reach 143 during the day using water for bathing, laundry, flushing the toilets?

On 2015-05-25 by Anonymous

Where is the correct location for installing a water heater? On first level of home or in attic?

On 2015-03-20 by (mod) -

Lois I'm not sure what question to answer here.

For a tight crawl area the starting place is to discuss with your plumber what fits without compromising the installation. Hooking heaters in parallel or series is one of several ways to get more hot water. The decision depends on your anticipated usage pattern.

On 2015-03-20 by Lois

Searching for right answer to my issue. Summer beach home, east end of Long Island. Home used from April-October with July-August rental. Present 50 Gallon Rheem that doesn't owe me a dime needs replacement after 20 years. We drain it at end of season.

So since I only have 49 1/2 inches in the crawl space and the low boy there is I think 46 (don't have my papers in front of me) in order to simplify my replacement woes, I was thinking two (2) 30 gallon Electric HWH's side by side, this way I have the height space needed for extra piping.

I read the above thread with the "boyfriend" plumber but still uncertain how to hook them together parallel or in series so one takes over if the other runs out of H/W.

My plumber will do it but I want to make sure its a proper fit. I"m sure my plumber may know but I need to understand it myself to see if that is my option or I have to continue to search for a 50 gallon low boy that isn't going to cause issues from the get go as all the reviews show mostly breakdowns or poor performance.

We've never had an issue with the Rheem but that was then and this is now in quality. Thank you. Lois

Question: is it more efficient to turn on the electric water heater just when needed?

I have been arguing with a landlord who believes it is more efficient to turn on the electric hot water heater to get the water to temperature then shut it off until it is necessary to heat it up again.

It is possible with this small apartment water tank to have a few showers and wash dishes without the water getting too cold but l argue it is more efficient to leave it on and use less electricity to MAINTAIN the water temperature that to shut it off and have to reheat the whole water tank from cold to hot.
Who is correct? - Thanks - Dave 5/20/11

Reply: it depends ...

I'm afraid that the answer to the efficiency of turning off a water heater is ... it depends. Indeed it is common practice to install a timer on electric water heater systems to turn off the heater during long periods when it is not needed - a step that is reported to cut water heater operating costs

In my OPINION, for a building where hot water is in use at normal frequencies, people run hot water periodically during the day: morning bathing, dishwashing, hand washing, and evening bathing. In those cases it is certainly more convenient and functional to leave the water heater on.

And the standby losses from a water heater that is in frequent use are low with modern insulated units.

For a building where hot water use is intermittent, with days or longer between use, there will usually be a savings from turning the water heater off, though there is the inconvenience of waiting for it to re-heat when occupants re-enter the building.

A common approach to economizing on electric water heater operating costs is the installation of a timer that turns the heater on and off at times to assure that hot water will be available when the occupants need it (and in order to comply with common rental agreement contracts that require the landlord to provide functional utilities).

Other Steps to Save on Electric Water Heater Operating Costs

Besides installing a timer on the electric water heater you can

- install heat traps on the plumbing lines atop the water heater to stop hot water from rising out of the water heater by convection when no one is actually running hot water in the building

- lower the water heater set temperature so that water is not heated more than needed and also so that there is no scalding risk

- install mixing valves at the heater or fixtures

Watch out: we do NOT recommend adding insulation to the water heater tank to try to safe energy even though some other websites make that suggestion. Modern water heaters are insulated by the manufacturer.

Adding insulation can void a heater warranty and worse, if improperly installed (such as covering or blocking a pressure/temperature relief valve) it can be dangerous. Do not add insulation to a water heater without first checking with its manufacturer.

Question: smelly foamy hot water coming from Triangle Tube Indirect Water Heater: antifreeze leaks into the system?

I woke up one morning to foamy and smelly hot water. I called my heating and a/c guy and he told me my TT TR45 was releasing antifreeze into my hot water. The HWH was only 9 yrs old and still under warranty but the company wanted the unit back to check what happened (they would not admit their product was faulty).

My plumber was sure the HWH was the problem and we replaced with a new Triangle Tube model (they no longer make TR45....wonder why...) since we were sure it would be covered under warranty. Now, Triangle Tube said the chamber had collapsed and it was not their product's fault but ours!!

They said the outside pressure (from the boiler) made the chamber collapse. I'm so mad at them!! We did NOTHING new or different to make the pressure change! I wouldn't even know what to do to make the pressure change!

I was wondering if anyone here knows what could have made this happen that Triangle Tube is trying to cover up. Please help!
Thank you in advance! - Annette 3/9/12

Reply: a Triangle Tube brand indirect water heater

Annette,

You're describing a Triangle Tube brand indirect water heater. In these systems water from a heating boiler circulates in a heat-exchanging coil placed in the water heater tank.

I'd like to see more details about what the manufacturer has said and diagnosed about your warranty claim.

A residential heating boiler normally operates at pressures under 30 psi; if pressures from the boiler, say in the zone heating your water heater, were higher than that, the pressure/temperature relief valve on the boiler should have opened to relieve the unsafe pressure, and you ought to have seen evidence of that discharge from the relief valve on your heating boiler.

There are things that can cause abnormally high heating boiler pressure. You should check the pressure readings on your heating boiler gauge, or have a service tech do so with an accurate independent gauge, just to be sure we don't have a double fault - an overpressure in the boiler and a relief valve that is not opening - that would be a very dangerous situation.

If you rule out abnormal boiler pressure, and if I understand that by "collapse" you mean that the water heater manufacturer says boiler pressure blew out their coil inside the heater, then at least so-far, things just are not adding up.

Perhaps you can ask the heater company to give a clear explanation of what they believe happened - in writing - so that we can understand the situation better. After all, as you'd point out to them, if there is something in the rest of your heating system that is improper it needs to be properly understood so that it can be properly repaired.

Reader follow-up:

Thank you so much for your reply. Here's a little more info....and, yes, it is a TT indirect water heater.

TT was saying that the inner chamber collapsed due to external high pressure. We had fully working pressure valves on both the boiler and the HWH. When the HWH was removed, it was full. There was no water on the floor and nothing had collapsed.

Upon removal and the "abuse" of moving the heavy thing outside, my contractor said that the HWH released water in the driveway (he believes that was when it collapsed).

I asked the TT company to give me a full explanation and I even suggested they send a rep here to check out the boiler room. So far, I have not heard from them.

In your opinion, what could have caused the HWH to malfunction?
Thanks again!

Question: un-vented electric water heater leaks

I have an unvented electric water heater(EWH) which is supplied by a flow pump.

A few minutes after it starts to heat up the water, the relief valve starts leaking. The EWH and valve are newly installed. How do I solve the problem. I suspect that the valve is cheap version set to low pressure. - Dave 8/13/2012

Reply:

Dave,

Indeed an electric water heater does not need a flue, vent, nor chimney.

Watch out: But a leaky relief valve is dangerous either because the system is at too-high a pressure or because a valve that is leaking for its own reasons (bad washer, dirt on the valve seat) can become clogged by mineral deposits and then fail to operate when it should in an emergency.

(see BLEVE EXPLOSIONS)

Most water heater pressure/temperature relief valves are not adjustable and are factory-set at a prescribed relief pressure (such as 150 psi), though we've seen some older TP valves on electric heaters that indeed could be adjusted.

Details on how to diagnose and fix this problem are

at RELIEF VALVE LEAKS.

Question: hot water is not evenly distributed in my house since a new water heater was installed

Hi,

The water heater was installed professionally and running smoothly since yesterday. After installation was done,

it seems that the hot water is not enough distributed to all other areas of my house such as powder room and kitchen (1st level), master bath (in sinks only – 2nd level), except for in the shower stall where the hot water is not the problem.

Also, just to let you know that before the installation, the old heater (Bradford White 50 gal, since 2000was leaking and that’s why was replaced) never had this kind of an issue. So, what do you thing is the problem now?

Thank you for your understanding,
Val 11/7/12

Reply:

Val,

Since your water heater is basically just that, a tank and heater, it should not directly have an effect on how water is distributed in the building - hot water leaves the water heater without knowing where it's headed.

But other things might explain your hot water distribution complaint.

A new, lower water temperature setting might make more distant fixtures run cooler at first use

A valve left partly closed would reduce flow rate downstream from the valve, as can some more subtle problems like a supply line partly blocked by debris or a solder blob, or by mineral deposits from hard water.

Question: cement water tank and hot water taps give off a fishy odor

We have recently moved to a house with a cement water tank all hot water taps give off a strong fishy odour the cold does not - Carolyn 11/24/12

Reply:

Carolyn

I'm not sure what the cement water tank is or what it has to do with your hot water supply.

See HYDROGEN SULFIDE GAS. The odor source in a water heater is often found to be a contaminated hot water tank (bacteria) or a bad water heater tank

anode (ANODES & DIP TUBES on WATER HEATERS).

On 2014-06-09 by Anonymous

i rent from a bad guy. He shut off the wall switch - which shut off the fan. Before, if I turned on the wall switch - the AC went on. Now, it doesn't. Inside my apt the AC and Furnace breakers are fine. 3 hours later, the bully shut off the gas water tank downstairs - turning the switch horizontal, then setting it to off and vacation, so the pilot light is out.

I cannot relight the pilot - turn on the gas line, hold down the pilot valve - won't light.

I cannot find a way to turn on the Rheem Criterian II gas/AC unit. What else needs to be turned on? Thermostat (Honeywell) does not ignite the AC or fan or heat - but it could not possibly be the thermostat as the person who shut off the fan switch - also turned off the water heater.

On 2014-04-22 by (mod) - improper combustion and the only thing that has not been tested yet is the fuel.

Dan with all due respect, and limited by having no actual view of the building, equipment, & installation I just cannot assume that all of the prior checks that you describe were complete, accurate, and correct.

Diagnosing a problem remotely is of still more limited effectiveness, as all I can do is suggest the areas where problems often lie. Regarding "everything has been checked",

In my experience, nearly 100% of the times that I have gone to a building where someone had previously described a problem my on-site visual inspection found important considerations that had not been included in the discussion - that no one thought to mention.

You need to be sure that the people on-scene are experienced and thoughtful.

On 2014-04-22 by Dan

I do have an air exchanger on my furnace because I have 3 fireplaces in my home. It is to equal air presure in the house so the fireplaces vent.

The furnace is in the same room as the water heater and the air exchanger. They checked the air exchanger last year as well and said its functioning normal. So they ruled that out already. Like I said in my first post everything has been checked and rechecked over and over. Nobody can figure out why this is happening.

But I think the same thing improper combustion and the only thing that has not been tested yet is the fuel.

On 2014-04-22 by (mod) - carbon dust caused the vacuum to explode

Well that's encouraging and says something about the limits of speculation about what's going on with mechanical systems when we're offsite and texting.

Still, we want to know why there is so much soot being produced. Generally it's a symptom of improper or incomplete combustion or improper venting - which is why I've been worried about system safety.

When you report that the sooting problem has occurred across a number of gas fired appliances installed in the same location and venting through the same chimney or vent system, then one tends to suspect the fuel, combustion air or venting system rather than the appliance, though I suppose the same installer might be making a similar mistake across multiple installations.

On 2014-04-22 0 by Dan

I was told by the service tech and he told the insurance adjuster that he thought the carbon dust caused the vacuum to explode similar to a grain dust explosion in a grain elevator.

He checked the gas lines in the house for leaks before he started the vacuum. And the gas was turned off at the tank at the time.

I had not considered that the vacuum explosion was because of a gas leak inside the house. I have never found a gas leak inside the house. And I have had this done 5 years in a row now. Every year they check my system for gas leaks before they install the new water heater. 5 water heaters in 5 years now.

The propane supplier last year installed all new presure regulators one on the tank and one on the house and tested the supply for leaks and presure. They tested it all again this year and found no problems or leaks.

They tested the line presure at the water heater and the furnace both were good.
All that was done prior to his cleaning of the water heater with the exploding vacuum.

On 2014-04-21 by (mod) -

When we hear about a heating device that produces soot as you describe, it should be patently obvious, even to a beginner servicve tech, that just vacuuming out the soot is not fixing the problem, and the equipment is unsafe to boot.

On 2014-04-21 by (mod) - exploding vacuum cleaner

Dan the exploding vacuum cleaner detail argues for a gas leak, perhaps inside the device.

So we've got two hazards to watch for: production of soot often means production of dangerous CO, and exploding vaccuum cleaner while vacuuming the heater argues for a combustible gas leak in the area where the vacuum was operating.

keep me posted and stay safe.

On 2014-04-21 by Dan - Thank You for the warning on CO.

Thank You for the warning on CO. I do have a CO detector in the room with the water heater for just that reason. Got it 3 years ago. It has never shown any signs of CO over the 3 years it has been in operation.

And again I have had everything inspected last year when this water heater was installed. Vents connections all was told to me to be in perfect condition and my "problem" was solved I would not have this new water heater carbon up on me. That was said last year and I said we will see about that,

I bet I will have you come out again next year to fix it again. He said at that time well we do cover it under warranty so if that worst case happens we will fix it at no cost to you. I said fine see you next year.

And here we are next year same problem.

They have no idea what caused it, The carbon build up which shut down the water heater. It is an on going problem now 5 years running. Until my basement is cleaned out end of this week I will not be able to have anyone work on the water heater problem.

It is working now after he cleaned it. How well I do not know. I may be burning an orange flame right now for all I know. I can not insect it til the hazmat team is finnished cleaning the basement.

On 2014-04-21 by (mod) -

Dan,

Check for propane gas leaks anywhere in the system both when the heater is OFF and when it is ON and operating . Normally you should smell the mercaptan additive intended to give a clue about gas leakage, but if the leak is inside the heater and if it vents up the chimney the leak may not be obvious to the nose of the sniffer. TURN OFF the GAS SUPPLY until this question has been resolved.

as it may assist other readers I am preserving our comment exchange at

inspectapedia.com/plumbing/Gas_Hot_Water.htm

where we discuss gas hot water heaters. There we may add additional citations & information.

Daniel

On 2014-04-21 by (mod) - check for contaminated propane.

It will be indeed interesting to check for contaminated propane. We don't know a thing about your fuel supplier, but once a year or so we do read about a fuel supplier, usually for heating oil not propane, who was fudging a bit on what they were delivering.

But one would think that if the problem were bad propane fuel, many other consumers in your area, served by the same propane delivery company, would be having similar problerms.

WATCH OUT: because of the risk of a fatal carbon monoxide poisoning problem the priority of attention should be

1. assure that there are working CO detectors (carbon monoxide detectors) at proper locations in your home

2. Have the heating equipment, chimneys, vents, connections, inspected for safe proper construction and installation

3. Check that proper combustion air has been provided and is not ever subverted by say a closed door or operation of a vent fan.

Where safety is concerned, a "sign-off" without being dead certain about the qualifications of the inspection person and the care of the inspection leaves me nervous. I've run into near-fatal safus involving too many assumptions and sign-offs.

Usually your best bet is to contact the company who made your heating equipment - they have a great interest in its safe, reliable operation.

WATCH OUT AGAIN: your story of an exploding vacuum cleaner is a strong suggestion that un-burned combustible gas was being vacuumed by the service technician. Most vacuum cleaners use rather modest motors that spark continuously and will certainly ignite an accumulation of combustible gas.

On 2014-04-21 by Dan - exploding vacuums, sooty water heaters, dangerous conditions

Addendum I now have insurance adjusters that want to pull a sample of propane from my tank to have it tested.

On 2014-04-21 by Dan

The vent is PVC pipe it runs up 3 feet and out side of the house another 3 feet. It is 4 inch PVC and all of it was replaced last year including the vent cover on the outside of the house all done according to code and signed off by a building inspector

because I demanded it last year from all involved parties. I did not want this to happen again but it did anyway this year. It is a powered vent with a presure switch that is supposed to shut down the water heater if it is not venting properly. That switch has never kicked out.

I can add now a horror story after the fact. The plumber came out to fix my hot water heater. The one I have installed now has a 6 year warranty I pay nothing for repairs or maintainence for 6 years.
And the install was certified by a building inspector as well to insure this warranty.

So anyway the plumer comes out and I tell him if the tanks burner is full of carbon again then please replace it as its efficientcy will go down even if you do just clean it out. Then I went to work. I get a phone call 3 hours later. He cleaned it and well the bad news.

I say what... He says his vacuum cleaner he was using exploded on him and filled my finished basement with a black cloud of carbon dust. He called his insurance company and they sent out a hazmat team to clean out my basement.

Clean the furniture and the entertainment center equipment and several ultra high end computers systems all need to be opened up and cleaned the washer and dryer they opened up and cleaned out the motors and the circuit boards etc.

7 guys cleaned Friday and now today and all this week they expect to be done by this friday.

So I said to the plumber wouldn't it have been cheaper to just replace the water heater like I asked. He said his boss told him the same thing.

So my wife is ready to sell the house we had to evacuate our house for Easter so much for our family get together. This is really getting to us. Everybody I have talked to about this says they have never seen a problem like this before.

On 2014-04-19 12:41:59.554580 by (mod) -

Dan I can only *speculate* as information is very incomplete in your question, but

WATCH OUT: it sounds to me as if there is a combustion air or venting problem that risks production of dangerous, even fatal carbon monoxide gas.

Normal burning of propane gas produces CO2 and water vapor if combustion is complete. If combustion is incomplete because of any reason the result is CO - carbon monoxide.

You should start with an inspection of the flues, vents, chimney connections, chimnney, and combustion air by a qualified expert, perhaps a chimney sweep and a qualified heating technician or by your local gas provider and building department.

On 2014-04-19 by Dan - propane water heater. It builds up a very thick layer of carbon insid

I have a propane water heater. It builds up a very thick layer of carbon inside on the burner area.
It has done this now for 5 years in a row. I have replace 5 water heaters in 5 years.

My problem is I can not get anyone to properly fix my issue. I have had 3 different plumbers come out over the last 5 years. I have replaced the water heater every year now for 5 years in a row.

I have spent more than $9,000 on water heaters and repairs in the last 5 years. The propane company has come out every time and checked everything line presure is good presure regulators are checked, I also have a propane furance which uses the same propane feed and has no issues.

I suspect contanimation in the propane tank but the propane company disagrees mainly because my furance has no issues. Is their an independent testing lab that I can have come out and draw a sample from my propane tank and test it?

Perhaps I should add that these 5 water heaters have all been different brands. I was thinking it might be a problem with the water heater itself but seeing as all 5 have all had the same problem with carbon buildup and we are talking about 2 inches or more in a year enough to plug up the vent stack which is powered by the way and that causes the shutdown of the tank.

Sometimes the gas valve sticks because of the buildup which causes the shutdown.

But anyway it is all the same problem excessive carbon and lots of it.

And all they do is replace the water heater with a new one. Every plumber says they have never seen a water heater look as bad as mine does. They are all stumped and so am I. Quite frankly I am at the end of my rope with this.

...

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