Intermittent loss of hot water


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Old 11-15-15, 02:35 PM
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Intermittent loss of hot water

I'm having a problem at my rental unit. Any insight and troubleshooting suggestions would be greatly appreciated, before I have to call in the plumber. My tenant describes the problem as follows:
"Periodically we are losing hot water (barely a trickle). The cold side is working fine. We noticed it's happening on the weekends after we do laundry, even on cold. It takes a good day before we get hot water again. Not sure if it's a combination of running the dishwasher and washing machine, however this has not happened before. This has been happening for about 3 weeks."

I've read threads about people having a similar problem, but they all seem to have a consistent loss of hot water, while my issue is intermittent. FYI I've never drained the water heater. I will be doing that now that I'm aware of that being an important part of water heater maintenance.

Thanks
 
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Old 11-15-15, 02:43 PM
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Let's start with the type, of hot water tank that you have (make & model #). Is there a separate hot water tank or is it the coil, in the boiler. The make & model, of the boiler might help too. Was any work done in the house, in the last 3 weeks?
 
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Old 11-15-15, 02:49 PM
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Could be lots of things.
Electric or gas?
What size heater?
To small a heater.
One of the elements is burned out.
Dip tube broke off.
 
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Old 11-15-15, 03:01 PM
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Thank you for the replies.

It's a little electric water heater, just one tank. The model is not legible. The make is Rheem Ruud. 30gal. No work has been done recently. The water heater is at least 7 years old. It's been functioning properly up until now.
 
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Old 11-15-15, 03:13 PM
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duplicate post, sorry.....................
 

Last edited by nataliejean1234; 11-15-15 at 03:14 PM. Reason: duplicate post, sorry
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Old 11-15-15, 03:40 PM
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(barely a trickle).
Correct me if I'm wrong. "Barely a trickle" tells me that it has nothing to do with the water temperature. It has to do, with the pressure. So the next question is: Is the pressure loss, in all fixtures?
 
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Old 11-15-15, 03:41 PM
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Thirty gallon is mighty small for an electric water heater.

Before going any further I need a better answer than "losing hot water". Does the actual FLOW of water (regardless of temperature) diminish from the hot tap or is it a matter of the TEMPERATURE not being high enough although the flow is the same as the cold?

Loss of temperature would be consistent with that size of water heater IF you used more than about 20 gallons of hot water. Electric heaters are the slowest to recover so it could easily take a couple of hours, depending on the size of the elements, to recover to a full tank of hot water.
 
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Old 11-15-15, 03:53 PM
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There is a loss of any temp of water (only a trickle) on the hot water side. Cold water does not flow thru the hot side when the problem occurs. This issue affects all fixtures.

I agree it's small, but that size has been adequate for 7+ years. These tenants have been there 5 years, and they haven't changed their usage habits.
 
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Old 11-15-15, 05:15 PM
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Cold water does not flow thru the hot side when the problem occurs. This issue affects all fixtures.
If this means that you have a significantly decreased flow on ALL fixtures, that "fixes" itself after a day or so it points to some kind of foreign material in the main piping between the water heater cold inlet piping and the first branch from the hot water outlet piping from the heater. This could be almost anything and the cure may entail replacement of the heater and perhaps even some of the piping. Do you know if there is a "tempering valve" (anti-scald valve) in the hot water piping near the heater itself?
 
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Old 11-15-15, 05:32 PM
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Although I'm not able to look at the unit right now, I'm pretty sure this water heater does not have a tempering valve. It only has a shut off valve (gate valve?).

Should I be calling a plumber or is there some troubleshooting I should do first?
 
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Old 11-15-15, 05:39 PM
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A gate valve could have the gate break from the stem and severely restrict the flow of cold water into the tank, which would severely restrict the flow out of the tank as well but It is doubtful it would "fix" itself over several hours and then again fail in a short time. Not impossible, depending on how the piping runs, but it would be a really rare occurrence.

It could be a piece of just about anything inside the tank that plugs the outlet of the tank and then after several hours drops out to be picked up again at a later time.

I'm sorry, that is my limit of information.
 
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Old 11-15-15, 05:48 PM
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Could draining the unit fix the issue? Should I try that before calling in the professionals?
 
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Old 11-15-15, 06:05 PM
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There is a small chance that draining and flushing could help but there is a good chance that attempting to drain after all these years will either plug the drain valve or uncover some weak spot in the tank that will cause it to fail in a very short space of time, maybe both.

I hate to recommend replacement without knowing that the heater is definitely the problem. Seven years on an electric heater is a fairly short lifespan, they usually last ten years or sometimes longer depending on the quality of the water and the amount of maintenance done.
 
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Old 11-15-15, 06:24 PM
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Ok, thanks for your help.
 
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Old 11-16-15, 04:23 AM
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Open the drain valve for a minute just to see the color of the water. Sometimes sediment is in the bottom but you won't see the color change when you run the water.
 
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Old 11-16-15, 11:52 AM
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I will try this tomorrow, thanks.
 
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Old 11-17-15, 06:24 AM
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Barely a trickle means that something is clogged. No doubt about that.

Heat traps (look like pipe nipples) sometimes installed at the inlet and outlet on top of a water heater, can clog becuase of a small pebble or some sediment that came in from the water main. There are plenty of other places in the hot water path that can get clogged with sediment.

Every time they flush the water mains, some sediment is stirred up and takes a few hours to settle back down. You don't know about it until you come home and get "milky" or "rusty" water for a minute or two and by then it is too late. Some may have gone towards the water heater and clogged something up in the path.
 

Last edited by AllanJ; 11-17-15 at 06:52 AM.
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Old 11-17-15, 04:03 PM
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Update: Thank you everyone for your help. While I was doing some trouble shooting, I closed the gate valve that controls the incoming water. When I reopened it, it started to leak heavily. The valve hadn't been turned in 7 years, so I guess that's why it failed. Just my luck. I was in a more emergency situation than before and I created the new problem myself. Very frustrating. I called a plumber immediately. He had to replace the gate valve (now a ball valve) and some pipes. Then replaced the heat trap (as y'all had mentioned) to remedy the original issue posted on this thread. Unfortunately, he said that it's a 50/50 chance it will work because he couldn't find the plastic ball, which may clog it again. He said I'll have replace the heater if it keeps happening. I'll have to pay $400 for the installation not including the heater itself. Is that a fair price from a licensed plumber?
 
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Old 11-17-15, 06:16 PM
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A problem with a heat trap will not force you to replace the entire water heater unless the act of removing the heat trap damaged where it was screwed into the heater.
 
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Old 11-18-15, 08:38 AM
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According to the plumber, the piece/ball from the old heat trap may be lost in the water heater and could reclog it, unless it was in the copper pipes he replaced. How can I have the 'clog' removed without replacing the heater? It hasn't reclogged yet, but was only happening once a week before. So I will have to wait and see it it malfunctions again. There is no damage where the heat trap was replaced, to my knowledge, since nothing is leaking.
 
 

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