Removing debris that clogged a water heater outlet and plumbing faucets (C) D Friedman R ArlyckHot Water Heater Repair FAQs
Cylinder Calorifier Diagnose & Repair

  • WATER HEATER PROBLEM DIAGNOSIS FAQs - CONTENTS: questions & answers on how to diagnose and fix problems wit a water heater
  • POST a QUESTION or READ FAQs about how to identify & diagnose problems with building water heaters, cylinders, calorifiers, geysers, hot water tanks, heaters, piping, pressure, flow, quantity, temperature, safety, noises, or other hot water troubles.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Questions & answers about how to fix a water heater that is not working at all or is not working adequately.

Water heater or calorifier or geyser diagnostic FAQs.

Let's make sure you are taking the quickest and most economical approach to understanding, diagnosing, and fixing hot water system complaints like loss of all hot water, poor hot water flow or pressure, hot water that is not hot enough, running out of hot water, or hot water heater operating cost, noises, leaks, or maintenance.

This article series describes the starting point for fixing problems with a building hot water supply.

Green links show where you are. © Copyright 2017, All Rights Reserved.

Hot Water Troubleshooting Diagnostic Guide - Basic Questions

Leaks at a double water heater installation (C) D Friedman

These questions & answers about how to repair a water heater were posted originally at WATER HEATER PROBLEM DIAGNOSIS - topic home; be sure to check the repair procedures given in that article.

On 2017-07-09 by (mod) If i hardly have any hot water does it mean i need a new water heater


Not necessarily. First let's diagnose the cause of the problem.

That will tell us if you need a new water heater or if we simply need a relatively inexpensive repair to the heater that you have. In the article above you will see a discussion of hot water quantity and also a link to an article on improving the quantity of hot water. And both of those places you will see a description of the common causes of the problem of not enough hot water.

For example if your water heater is an electric model it could be that you simply need a heating element replaced.

On 2017-07-09 by Gloria

If i hardly have any hot water does it mean i need a new water heater

On 2017-06-15 by Rizwan

I have replaced the float at least four times in a year.
It always gives up causing the water to overflow

On 2017-06-14 by (mod) Pilot only comes on when you turn the temperature down to very hot

To me that sounds like a bad temperature sensor or thermostat control

On 2017-06-14 by Danielle

Pilot only comes on when you turn the temperature down to very hot

Hot water only comes on when you turn the temperature on very hot

On 2017-05-06 by Anonymous - hissing noise from our water heater,

If the water is coming out of the temperature pressure relief valve then the pressure is too high or the valve is leaking and needs to be replaced.

If the pressure is too high the problem could be incoming water pressure or it could be the the temperature of the water heater was set too high if the water is leaking from the heater itself then the heater has a leak.

If the leak can be traced to a plumbing connection it may be repairable. Otherwise the heater probably needs to be replaced.

Hissing often is traced to leaks that are draining down to the bottom of the heater, right over the burner. When the burner is off you'll probably see water.

On 2017-05-06 by A.ditto

I heard a hissing noise from our water heater, turned off the power and the hissing stopped, but then I heard water, the water continues to run without stopping, goes from water heater to pipe into pan at the bottom and drains, I turned off the water. Any ideas?

On 2017-05-01 by Stu Boyd

The burner and pilot light on my hot water heater are functioning, but the water does not appear to be heating.

On 2017-04-30 22:04:34.893768 by Kenny

Hey Dan Joe,

I have already swapped it with a good zone valve then that zone valve I put on another zone it it worked. Can't be a zone valve. Any other ideas

On 2017-04-29 00:02:48.982998 by (mod)

It sounds to me like a bad zone valve.

On 2017-04-27 16:07:05.062829 by Kenny

I have a super contender water heater a burnam oil heater with Taco valve heads for each zone (3 zones) taco switch board that lights the zones.
I have not been getting hot water and no heat.

I switched burner off and the hot water calls to aquastat but get nothing. Just zone light on switchboard. Burner is turning on only to stay warm around 200.
I switched the hotel water priority zone to off and the heat works. But still no hot water.

I shut it all Down then took the zone valve head that I know worked from heat zone and swapped it it's hot water zone head. It worked I got hot water but just once never kicked back on. Then noticed the zone head I switched from hot water zone still worked on other zone for heat.
Is this my aquastat?

On 2017-04-19 by Becky

I had a water leak outside my house and now my hot water heater is not working. Any suggestions for troubleshooting this problem?

On 2017-03-16 by (mod) Power outage twice then water heater stop heating

Was the outage from an external source or is your own building's electrical wiring and service unsafe?

Check the reset buttons on the heater's thermostat

On 2017-03-16 by Anonymous

Power outage twice then water heater stop heating

On 2017-03-12 by (mod) - why hot water temperature varies wildly

Ruling out normal conditions such as someone using most of the hot water then someone else finding tepid water at another tap - I would guess that the thermostat on your water heater is not working properly and needs replacement.

On 2017-03-12 by Gary

One week the water temp is VERY hot and the next week it is back to normal. Why?

On 2017-03-06 19:49:45.164030 by (mod)

If the poor hot water flow is only at this one fixture then I suspect that a hot water pipe or elbow or control close to the tub itself is clogged or closed.

On 2017-03-06 19:10:52.053972 by Anonymous

On the tub I turn the hot water on but It barely comes out cold water comes out good what can be the problem

On 2017-02-06 17:10:49.585987 by Lawrence

I lowered the temperature of the hot water heater to a very low setting. When I tried to run the hot water the pressure was very, very low. I had to leave on a trip so I turned off the water and gas to the unit and have not returned to the house to ck the water heater yet. Could lowing the water temperature have caused this problem?

On 2017-01-22 00:15:19.935432 by (mod) releif valve has been replaced was ok for couple months and now has started leaking again


Over at RELIEF VALVE LEAKS we list the common causes of leaks at these safety devices. When a new valve that's probably intact is leaking I suspect over-pressure or water hammer.

If your building's water pressure is in a normal range, AND if the right relief valve was installed on your heater, then look further into


WATER HAMMER NOISE as if there is a banging sound when you close a hot water faucet that force could be triggering the TPR valve leaks.

On 2017-01-21 by ron

releif valve has been replaced was ok for couple months and now has started leaking again?

On 2017-01-13 by (mod)


Relying on just the information in your question, I really don't know. However water leaks into the burner or into controls of a water heater could certainly prevent it from operating.

On 2017-01-13 by Monica

I noticed a leak from a gray pipe coming off the water heater, I was wondering could the leak caused the tank to not kick on/heat up? It's not leaking under the house at the moment, and I am still getting power to the hot water tank.

On 2017-01-09 by (mod) hot water tank drained an won't fill back up


If you open a nearby hot water faucet and then be sure that the water supply into your water heater is turned on water will fill the heater while pushing air in the heater out through the piping and out through the faucet.

If you follow the instructions I just gave and water still never entered your water heater then either of valve is closed that needs to be opened or are there still a frozen pipe.

Take care if your water heater is electric. Never turn on an electric water heater until you are sure that all of the air has been removed. Otherwise you are very likely to burn up the heating element.

On 2017-01-09 by Christina

Pipes froze an busted pipes hot water tank drained an won't fill back up but have cold water coming out of faucets what is wrong please email me with any ideas

On 2017-01-03 by Bill

Hot water tank pitot light goes on then after awhile it goes out. Boo hot water

On 2016-12-15 by Joanne

Have a oil hot water furnace, have hot water but no heat in the radiators. Went to check furnace there was water on floor. But furnace running, what should I look for? Have oil and hot water but no heat.

On 2016-10-08 by ollie

sorry that anonymous post was myself i forgot to add name at the beginning of the comment

On 2016-10-08 by Anonymous

ill try and get some pics sorted. the float control is brand new just been replaced. the ballcock control is feeding cold water into the boiler tank. so when i run the hot it takes it from the hot tank and then when the level dips the callwater feed tank puts more into the hot water tank.

ive looked at some vids on you tube and am wondering if i did something wrong after draining all the tanks. i.e. i may have left the hot taps open. is there a correct procedure to refill all the tanks to help keep pressure and prevent airblocks in the system??

thanks for your comments they are much appreciated.

On 2016-10-04 by corpussalus

What should I be concerned about if the hot water coming out of my kitchen sink (nearest to the hearter) seems to be extremely high pressure that jumps out..makes the faucet too hot to touch, and has a lot of steam coming directly out of the tap..I'm afraid to use it

On 2016-09-28 by (mod)

This is not a system familiar to me: I'd sure appreciate seeing some sharp photos via the page bottom CONTACT link.

Having to run the bath to get "water pressure going" sounds as if a float control was sticking - perhaps the ballcock.

Is that ballcock control filling up the water heater, or delivering water from it?

On 2016-09-26 by ollie

just seen an error below call water tank is about 9ft in the air not 5ft.

thanks for replying.

i know nothing really about plumbing. ill try and best explain my system but like i say im not technical.

teh system is v old. its based on an electrically boosted element into an old boiler. it boosts during early hours of morning to give heat the whole day. the boiler itself it located in a cupboard at floor level in the lounge. the cold water feed is the other side of the room again boxed in about 5 ft high (built into the roof). my bathroom then is split level to the lounge so height wise its heigher then the boiler tank but obviously lower then the cold water feed built into the roof.

up until the ballcock valve was replaced everything worked fine. on a morning if you wanted good pressure, i just ran the bath for 30 seconds and then the pressure was so that the hand basin and kitchen hot tap would run fine. so it seemed that the bath tap helped to get the pressure going the others not so much.

after the ballcock replaced. in the same scenario first thing in the morning i would run the hot tap and it just stays at a trickle. the contractor blames this problem on the tank being completely emptied (boiler tank i mean). its the first and prob last time i would do this but didnt realise emptying you boiler tank would create such problems with pressure.

i forgot to say the water still heats fine from the elctric element that boosts it. thats not the problem its just purely pressure and getting it up to a normal level when the tank hasnt been used say over night or been left the whole day and i come back at tea time to poor pressure.

i guess my real question is: if this is an airblock in my boiler tank, over time will this free itself or am i likely to have repeated pressure issues when i leave the hot water standing over a prolonged period of time.

sorry if im explaining this badly.

On 2016-09-24 by (mod) a very old cistern boiler tank in a top floor flat

Ollie, I'd like to help but I don't have a cleare understanding of your system, components, locations, operation.

Start by reviewing all control valves in the system as well as that ball float control valve; When you have cold water flowing out of both cold and hot faucets, then you can look further at why the water isn't being heated by checking the heater or boiler itself.

On 2016-09-23 by ollie

hi, i have a very old cistern boiler tank in a top floor flat. i had a tradesmen come to replace the ballcock in the cold water feed. rightly or wrong i drained the whole tank and now when we have filled the cistern tank up it appears that i have some air block.

i did a temp fix last night whereby i turned both hot and cold on the shower, put my finger over the shower pipe (with the head off) for 40 seconds and the water pressure returned. im conscious that any longer could have flooded the called water feed tank.

now when i have come in from work today, turned the hot water tap on, im back to poor pressure and non existent in the hand basin and kitchen sink.

please can anyone advise how i can fix the problem of the hot water flow and/or better way to free the air block from this old tank??? any help is much appreciated. thanks

On 2016-09-19 by (mod) STOP pressing the reset button

John: STOP pressing the reset button - you are risking a dangerous OIL BURNER PUFFBACK EXPLOSION - search InspectApedia for that phrase to see the details.

On 2016-09-19 by John

Had to press the reset button the past two days on my oil fired hot water heater. Why is this occurring?

On 2016-06-06 by Belinda Palmer

I just bought a recon wilson super x the water is not very hot at all. 😢

On 2016-06-05 by (mod )oil fired hot water heater not sparkling at the tip of the nozzle


Most modern oil burners use a continuous-on ignition: a spark created by a high voltage transformer makes a hot spark between the electrodes all of the time that the burner is "on", so that oil exiting the nozzle will be ignited. When you get no spark the common problems include a failed transformer, a lost electrical connection, or whiskers of oily crud between nozzles that are shorting them out.

On 2016-06-05 by Vincent

My oil fired hot water heater not sparkling at the tip of the nozzle to light the oil at the nozzle

On 2016-03-08 by (mod) Hot water runs real slow thru the hot water side of faucet


Take a closer look at and follow the two recommended links in item #2 in the above article where we describe slow hot water flow or poor hot water pressure.

On 2016-03-08 by Gerald skidmore

Hot water runs real slow thru the hot water side of faucet

On 2016-03-03 by (mod) Aero CF 32 T hot water heater won't run

Sounds unafe to me, perhaps an oil burner that needs service and repair. Do not keep pressing the reset button - you risk a dangerous puffback explosion. I'd ask for help from a trained service tech.

On 2016-03-02 by Tony

I have an old Aero CF 32 T hot water heater. At first it would not fire on its own, then we would be able to start it up manually, now it starts runs for less then a minute then shuts off. Please help.

On 2016-02-13 by (mod) narrow pipeline leading into the burner with a small faucet like shut off valve

You are describing what is probably the supply valve on your heater's oil line. It works backwards from what you think. Screwed fully down or clockwise is probably open. See

On 2016-02-13 by Jim Devine

Hi - I have an oil fired electric hot water heater. At the bottom there is a narrow pipeline leading into the burner with a small faucet like shut off valve. It's right in front and often the valve ( or wheel) gets accidentally turned off either clockwise or counter-clockwise.

It's in a space that can easily bumped as one passes it. . ( Once it apparently shut off b/c the movement closed it ) Which way is full open? Clockwise or counter-clockwise? Thank you. email>

On 2016-01-27 by william boy

I have AERO oil heating hot water heater. It is a side venting system, a bolt holds the internal cap on top of it. In this I should vaccum the sut out. This is needed, but I can't get the bolt to turn off. I have the correct wrench. What direction do i turn the bolt clockwise or counterclockwise?

On 2015-12-23 by (mod) new heater but no hot water


If you turned power on to the electric water heater before you re-filled it completely with water both the new elements will have burned out.

On 2015-12-22 by jay

I replace the water heater elements and thermostat and it has Pawer in all their elements and thermostat and steel don't have hot water any help

On 2015-12-12 by (mod) gas burner flame won't stay on

Sounds like a bad thermocouple.

On 2015-12-12 by vishal patel

Gas burner started but after 10 seconds flame shut off and not persist continuously

On 2015-12-07 by Kevin

I replaced both elements in the water heater don't have any hot water coming out of the faucets in bath room or kitchen can you help me

On 2015-11-23 by (mod) no hot water from small electric heater

The heater may have power "on" to it but the heating element may be burned out or its control thermostat may have failed

On 2015-11-23 by Anonymous

What could the problem be if a small electric water heater is running and there is no hot water coming out of foset only cold?

On 2015-10-19 by Wayne

I have an electric hot water heater in my garage to supply a sink only. When I run the hot water it spurts air continually while I am using it. Do I need to install a small expansion tank to take care of the problem? It gets used very little so I'm thinking that due to the heating and cooling of the water it produces air.

On 2015-07-13 by Dolores Devlin

There is sufficient oil in tank. Pilot lights on on timer. Neither room nor water heating available

On 2015-06-17 by (mod) Banging water heaters

Banging water heaters are often caused by mineral or lime deposits in the water heater - something your plumber can check. Ask the plumber also if your home has a water hammer problem.

On 2015-06-16 by Teresa

I have a richmond electric water heater that was here when I purchased house about 3 months ago. according to paperwork it is 3 yrs old. recently it started whistling and making banging noise.

then the pop off valve suddenly failed, so my husband replaced it hoping that would be the cause of the problem. It was not, it continues to pop off and make all the noise, so today my husband replaced the thermostats. Help what can we do now...replace the whole thing or is this something else causing it?

On 2015-04-28 13:59:24.237740 by (mod)

Thanks Bob, this is a snafu I've not come across. Your report will doubtless help other readers. It makes perfect sense: I suppose you removed the core to avoid damaging it during soldering.

On 2015-04-28 12:58:20.540130 by Bob

Thanks for the reply DanJoe! But i figured it out! I had replaced a valve body in a bathroom but didn't put the actual valve in it. This was allowing the hot and cold to mix at the valve body. I'm assuming the cold is at higher pressure than the hot and was back blowing through the hot water lines. Once i put the valve in, everything works like it should. <--- dork! lol!>

On 2015-04-27 by (mod) Whirlpool 50 gallon hot water heater gets hot but no hot water is delivered

Great question, or as Click and Clack used to say, you've stumped the chump. I can't figure this one out from just your e-text. It's the inconsistency as you describe it that's puzzling.

Turn on hot water at one fixture. Go to the water heater, feel the outlet pipe: is the pipe hot?

Check that the heater was properly connected: cold and hot MUST be connected to the proper mounting points on the water - which will be marked COLD and HOT.

Check that the dip tube was installed: if you left out the dip tube on the cold water inlet that can certainly foul up the hot water delivery.

On 2015-04-27 by Bob

I just put in a new Whirlpool 50 gallon hot water heater. The water heater is heating the water, but i get either no hot water or cold, then hot, then cold again at the kitchen sink downstairs, and luke warm to cold water at the faucets upstairs.

How is it possible to run the hot water side of a faucet for 10 mins and get zero hot water out of it when i know for a fact the water heater is heating the water? the pipe at the water heater is hot.

On 2015-03-10 by Nick

I have a solar water heater and it's been working great. But recently we've been having horrible weather and the electric backup isn't working. I'm getting 119/119/238v to the load side of the gray box but my waters staying at 90*F. I'm an electrician by trade so I know I'm getting the power to the system but dont know anything about water heaters or thermostats. Thanks for your help

On 2015-01-27 by (mod) My heater is spilling water out through the hole below the hood


It sounds as if there is a leak somewhere on the heater and that water may be filling up the space between the heater jacket and the heater body, sufficient to come out around the top. The heater is unsafe and should be shut off. Sorry.

Even if the leak is found to be just at a water pipe connection at the heater top, if all of the heater's insulation has been soaked you may need to replace it.

Use the email found at our CONTACT link at page top or bottom to send me photos for further comment

Keep me posted.

On 2015-01-26 by Sally

My heater is spilling water out through the hole below the hood what is my problem

On 2015-01-14 y gary

replaced element now staying to hot

whirlpool enercy smart replace element now staying to hot

On 2014-12-12 17:53:34.525560 by (mod) - how to avoid getting burned by the water heater

Phil, you are asking about the Bradford White Aero CF32 water heater. This is an oil fired, center flue hot water heating system that uses a single immersion aquastat or controller.

See the article titled


in the More Reading links just above.

For efficiency the water heater may produce quite hot, even scalding water. The company's installation instructions for the Aero CF32 specify that a mixing valve should be installed at the water heater's outlet.

Here is what the company advises about avoiding scalding burns

This water heater can deliver scalding temperature water at any faucet in the system. Be careful whenever using hot water to avoid scalding injury. Certain appliances such as dishwashers and automatic clothes washers may require increased temperature water.

By setting the thermostat on this water heater to obtain the increased temperature water required by these appliances, the potential for scald injury increases. To protect against injury, you should install an ASSE approved mixing valve in the water system.

This valve will reduce point of discharge temperature by mixing cold and hot water in branch supply lines. Such valves are available from the manufacturer of this water heater or a local plumbing supplier. Please consult with a plumbing professional.

On 2014-12-08 by Phil

How is the water temperature adjusted on aero cf32 hot water tank, it's to hot now

On 2014-10-23 by Cherise

PGE came out to turn on my hot water heater, only to tell me the pilot off-on knob is stripped. It is a 1974 Montgomery wards, model SRM 33475 Nat. gas. Any chance of locating a new knob. Or, should I resign myself to living with only cold water?

On 2014-10-07 by (mod) white flakes coming out of the hot water side of the faucet



On 2014-10-07 by chris

i have white flakes coming out of the hot water side of the faucet

On 2014-06-22 by (mod) Aero oil burner turns on only when we press the RESET button



STOP pressing the reset button. Pressing it more than once is flooding the combustion chamber with unburned oil, risking a dangerous puffback.

The repair needed may be a simple cleaning and tuneup but you need a trained oil heat technician on the job.

On 2014-06-19 by Ellen

We have an Aero oil fired burner on my hot water tank that has been working on & off for the past two days, but now not at all. No hot water. We have 3/4 tank of oil. Pushing the reset button on the burner makes it kick on, but it shuts off after 15-30 seconds.

It will keep kicking on each time you push the reset button, but always shuts off within a minute or less. Hot water tank itself was just replaced 4 months ago. Plumber said burner was still good, so he reused it. Any suggestions are most welcome.

Question: no hot water after draining the water heater

(Apr 26, 2015) Todd L said:
I drained the hot water heater and refill it and now it won't produce hot water any suggestion



Take a look at the hot water heater diagnostics beginning at


Perhaps you turned on an electric water heaeter while it was empty of water - burning up the electrodes.

Question: oil hot water heater wont re-start

(Sept 6, 2015) SCOTT said:

My oil hot water heater will not restart when the temp in the tank goes down why? I changed the aquastat, the oil burner control( protectorary). Please halp



The temperatures in an oil-fired water heater are sensed by an aquastat control, sometimes more than one of them depending on how the safety limits are managed. When the water temperature is below the cut-in temperature set on the aquastat the burner should fire.

But there are other controls that will shut down an oil burner such as a stack relay or cad cell sensor that detect flame problems.

It's time for a service call by a trained technician.

Question: gas hot water heater stopped working

(Oct 2, 2015) Carson said:
Gas hot water heater-unit is almost new everything was working fine then one day just stopped getting hot. Water is barely warm but when I pulled cover off it looked like pilot was still lit. Would a circuit breaker being switched on and off cause a problem ? The thermostat is set to on but no matter what setting it's on water will not get hot. What should I do next ?



Keep in mind that at your building you may have more than one of these conditions.

  1. No hot water: If you have no hot water at all, but cold water comes out of the hot water faucets, make sure that your water heater has fuel (oil or gas) or power (electric, solar).

    Also check for a defective high temperature limit switch (there is a reset switch on the thermostat) or for a defective upper thermostat (you'll have tepid hot water but no HOT water).
    See NO HEAT - NO HOT WATER: HEATER DIAGNOSIS for details about troubleshooting when you have no hot water at all.
  2. Hot water pressure or flow: if your problem is gradual or long-standing poor hot water pressure, or flow, that is, water comes out of the faucet or shower weakly or too slowly, start your diagnosis here
    at HOT WATER IMPROVEMENTS (the article below)

    Poor hot water flow, or bad hot water pressure, which is usually a piping or clogging problem, mineral clogging at a water tank or tankless coil, or an overall building water pressure problem. In the article below we describe how to improve hot water pressure and flow.

    If your hot water pressure has suddenly been lost but you still have some, poor hot water flow,
  3. Hot water quantity: if your problem is gradual or long-standing poor hot water quantity, that is your water is hot enough, but you run out of hot water too soon.

    If you do not have not enough hot water quantity, you are running out of hot water very quickly. Insufficient hot water quantity may be due to the way hot water is being made: a water heater that is too small, a tankless coil on a new small heating boiler, or an instantaneous water heater that is being asked to supply hot water too rapidly.

    Diagnosis and repair for hot water quantity are


Continue reading at WATER HEATER PROBLEM DIAGNOSIS - home, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.



Suggested citation for this web page

WATER HEATER PROBLEM DIAGNOSIS FAQs at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Ask a Question or Search InspectApedia

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman