Water temperature varies - why?


  #1  
Old 02-07-07, 11:08 AM
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Water temperature varies - why?

Hello -

I have rather an odd problem lately. The hottest water that comes from my hot water heater varies in temperature. Most of the time the water is nice and hot. Sometimes, though, it just won't get hot enough for a hot shower. The water is still warm enough not to be uncomfortable, but I love *hot* showers and it just feels lukewarm to me. It hasn't always been this way. It started happening in the past few months.

Usually morning showers are plenty hot. It's the shower in the evening that is at risk of not being warm enough. However, this isn't always the case. The lack of hot water seems to strike at random times. We run no water-using appliances during the day and never use hot water for cooking. I used to think it was because someone ran the washer or dishwasher on a warm cycle before I took my shower, but it happens when no one has washed clothes or dishes for days. There's only 2 of us living in my house and I know when my other half showers so it's not that either. Besides, when the water is hot, the two of us have never been able to make the tank run out of hot water.

We have a US Craftmaster natural gas water heater of indeterminate age (probably 10 years old or less) which was professionally installed. There are no leaks to speak of. The heater is set to the lowest temperature setting. We've lived in our house for two years without trouble from this appliance.

Do you have any ideas as to why this might happen? I turned the heat setting up one notch this morning to try to head off the problem, but I'm worried the heater might be ready to die.

Thanks!

Em
 
  #2  
Old 02-07-07, 04:41 PM
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If the heater is ten years old it is running on borrowed time. That doesn't mean that it is in immenent danger of failing but the "normal" lifespan of gas water heaters is a little less than ten years. Yours may go twenty years but I sure wouldn't make any bets.

Anyway, I'm thinking that the thermostat/gas valve may be faulty...or just plain tired. You adjusting it up to a different set point may be all that is necessary for it to behave for quite some time.

I do think you should be thinking seriously about replacing this heater.
 
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Old 02-07-07, 11:09 PM
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Thanks for the help.

I will start planning for the expense so I'll prepared when the time comes.
 
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Old 02-07-07, 11:55 PM
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It's always hottest just after heating up, and may cool some before the thermostat kicks in again. This apparently lazy behaviour is designed into all heating/cooling systems, so they aren't constantly switching on and off.

Try washing a few dishes in the sink, 15min before your shower. The goal is to have the heater finish heating just as you start your shower. You could use a watch, observe the flame, get this down to a science.
 
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Old 04-04-07, 10:10 AM
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domestic hot water temp goes up and down, your mixing valve has gone bad replace the element (watts mixing valve will last you about 2 years)
Originally Posted by double_agent
Hello -

I have rather an odd problem lately. The hottest water that comes from my hot water heater varies in temperature. Most of the time the water is nice and hot. Sometimes, though, it just won't get hot enough for a hot shower. The water is still warm enough not to be uncomfortable, but I love *hot* showers and it just feels lukewarm to me. It hasn't always been this way. It started happening in the past few months.

Usually morning showers are plenty hot. It's the shower in the evening that is at risk of not being warm enough. However, this isn't always the case. The lack of hot water seems to strike at random times. We run no water-using appliances during the day and never use hot water for cooking. I used to think it was because someone ran the washer or dishwasher on a warm cycle before I took my shower, but it happens when no one has washed clothes or dishes for days. There's only 2 of us living in my house and I know when my other half showers so it's not that either. Besides, when the water is hot, the two of us have never been able to make the tank run out of hot water.

We have a US Craftmaster natural gas water heater of indeterminate age (probably 10 years old or less) which was professionally installed. There are no leaks to speak of. The heater is set to the lowest temperature setting. We've lived in our house for two years without trouble from this appliance.

Do you have any ideas as to why this might happen? I turned the heat setting up one notch this morning to try to head off the problem, but I'm worried the heater might be ready to die.

Thanks!

Em
 
  #6  
Old 12-30-07, 08:32 AM
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Same Problem

I have a 7 Year old Craftmaster Envirotemp with exactly the same problem. I'm now at the highest setting. You can check the age by reading the first two numbers of your serial number. 00 is 2000, 01 is 2001, etc. I beleve the next two numbers is the week it was made. If you find a fix, I would be interested
 
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Old 12-30-07, 11:55 AM
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Welcome to the forums! Same questions...have you drained the water heater lately? Have you checked and/or replaced either of the elements and/or dip tubes? Are the thermostats working properly engaging on demand?
 
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Old 12-30-07, 02:48 PM
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same Problem

Drained it a few days ago. Very little sediment. Its gas, so no elements. Have not checked the dip tubes yet. The Thermostat kicks on quickly when under demand, Flame looks normal. My gut feeling is that the themperature control is starting to fail. As double agent and I have units from the same manufactuer I'm thinking it may be the same problem. I replaced my last unit, a Rheem during a remodel. It was still working fine after 20 years! Maybe I should have keep it.
 
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Old 01-02-08, 06:28 PM
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My issue as well

I have (2) 6 yr old, builder installed, 40 gal A.O. Smith gas water heaters Model# FSO 40 248. Morning water in shower is very warm, but not hot as usual especially in warmer months. I assume poster below is right about water setting overnight and receiving cooler water in AM shower until thermastat kicks in. Any replcement parts suggested?
Thanks.
Steve
Originally Posted by russkiy23
domestic hot water temp goes up and down, your mixing valve has gone bad replace the element (watts mixing valve will last you about 2 years)


I have rather an odd problem lately. The hottest water that comes from my hot water heater varies in temperature. Most of the time the water is nice and hot. Sometimes, though, it just won't get hot enough for a hot shower. The water is still warm enough not to be uncomfortable, but I love *hot* showers and it just feels lukewarm to me. It hasn't always been this way. It started happening in the past few months.

Usually morning showers are plenty hot. It's the shower in the evening that is at risk of not being warm enough. However, this isn't always the case. The lack of hot water seems to strike at random times. We run no water-using appliances during the day and never use hot water for cooking. I used to think it was because someone ran the washer or dishwasher on a warm cycle before I took my shower, but it happens when no one has washed clothes or dishes for days. There's only 2 of us living in my house and I know when my other half showers so it's not that either. Besides, when the water is hot, the two of us have never been able to make the tank run out of hot water.

We have a US Craftmaster natural gas water heater of indeterminate age (probably 10 years old or less) which was professionally installed. There are no leaks to speak of. The heater is set to the lowest temperature setting. We've lived in our house for two years without trouble from this appliance.

Do you have any ideas as to why this might happen? I turned the heat setting up one notch this morning to try to head off the problem, but I'm worried the heater might be ready to die.

Thanks!

Em
[/QUOTE]
 
  #10  
Old 01-02-08, 06:38 PM
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Originally Posted by furd
If the heater is ten years old it is running on borrowed time. That doesn't mean that it is in immenent danger of failing but the "normal" lifespan of gas water heaters is a little less than ten years. Yours may go twenty years but I sure wouldn't make any bets.

Anyway, I'm thinking that the thermostat/gas valve may be faulty...or just plain tired. You adjusting it up to a different set point may be all that is necessary for it to behave for quite some time.

I do think you should be thinking seriously about replacing this heater.
good ideas , i will try it maybe will save sum money
 
  #11  
Old 02-09-12, 10:36 AM
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Not sure where or how to post this, I have a US Craftmaster gas water heater, that is 6 yrs old, We had one of the flex hoses replaced, the plumber did it when he fixed our central heat unit, he had to turn the gas off,now for the problem, our water heater will NOT stay lit, we can light the pilot, but once we let go of the red button, the pilot goes out, what can be wrong?
 
  #12  
Old 02-10-12, 11:25 AM
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When you light the pilot, look at the flame. It should wrap at least partially around a metal "capsule" which has a small metal tube which leads back to your gas controller (where the red button is).

If the capsule (thermocouple) is being heated and the flame still goes out when you release the button, it is time to replace the thermocouple.

Get one the right length. Only about $10 or less at most big box stores. You should be able to replace it yourself with a few small wrenches.

Beware sharp sheet metal edges.
 
 

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