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Plumbing in the Home/Water heater runs out first thing in mornings



I've got a Kenmore Power miser 9 gas water heater. First thing in the morning it runs out of hot water all at once. Then if I wait 30 minutes it's fine the rest of the day and works like normal. I did some online research and tried a test where I shut off the cold water supply to the water heater and then turned on the hot water at the kitchen sink. I had a litle trickle. If I turn it off, wait a few seconds and turn it back on it develops a little more pressure. But it is definetely a steady small stream of hot water. So then I tryed turning off the hot water at all the sinks that had combo faucets. But that didn't change anything. The only ones left that have combos would be the two showers.

Does it sounds like the culprit would be one of the showers is passing hot to cold water during the evening?

Should there be a total abscense of hot water from any sink in the house when the cold water is shut off to the water heater?

How common is it for the valve that closes off the cold water to not shut off all the way?

thanks ahead of time :)


When the supply to to the water heater is shut off, there should be no water from the hot side of any faucet. Yes, it is very common for that valve to not seal especially if it has not been operated for a long time. If the valve is not seating tight, you will get a drip or trickle from the hot side. The cold water shut off to the heater controls all hot water leaving the tank. In the morning when you have no hot water, do you mean the water goes cold or that it stops flowing? If it is a temp. problem, the problem is in the gas valve. Let me know so I can better answer your questions.

---------- FOLLOW-UP ----------

QUESTION: Thanks Jay. The mornings it happens the water is hot enough but it runs out and goes cold way before it should. Its as if the temp is ok but the volume isn't. Happens a few mornings a month but not every morning. Seems like it's more frequent now. I turned it all the way to hottest which seems to fix it. But this is not an ideal solution as the water is so hot its almost steam and can burn.

Joe, the problem you describe is often caused by the gas valve temp. sensor not getting an accurate reading. By that I mean the valve probe is getting a false reading and not firing the burner. This can be caused by a couple things. One, the probe is covered with mineral deposits and thereby insulated from the water and not sensing a temp. drop or  two,the probe is just worn out. Also, it could be a weak spring in the gas valve itself and it only opens when the temp. swing is excessive. Like when a large amount of cold water is introduced into the tank as when a shower is ran.The tank, in essence, comes on too late and is not making up the temp. that is lost when sitting idol all night. I would replace the gas valve since that is the brains of the tank and will solve your trouble.

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Jay Nicholas


Plumbing & Heating (warm air, hot water & steam heat)


40 years in the business, 40 years as a lic. master plumber in NY State. Retired

Graduated Magna cum laude at the School of Hard Knocks

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Commercial, residential and light industrial. You name it ...I have probably worked on it

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