Lately I've been having problems with the hot water in my shower. It seems that I have to turn the hot water knob much further than I used to in order to get a good mix of hot and cold water. But the weird thing is, when I finally get a good mix of warm water it stays that way for a few minutes and then it gets really hot for about ten or fifteen seconds and then it gets really cold for about ten or fifteen seconds. After the "hot then cold" cycle, it will stay warm for a few minutes and then start the whole "hot then cold" cycle agian.
I haven't noticed any problems like this at any of the faucets throughout the house, but the faucets don't get left on for a long time. And, I only have one shower.
The water heater is gas and is about 12 years old. I just bought this house a little over a year ago so I don't know if any of the elements have ever been changed or if the water heater has been cleaned. I also thought about taking the hot water valve out of the shower to see if something got clogged in it.
Does this make sense? I hope someone can help me out here....
I would think that this has to do with the valve. One of the vavles in my old house was bad and after turning the shower on, if you tried to adjust the cold water at all, it would get really cold (no matter which direction you turned it). Check the gasket.
Sounds like the water heater might be going bad, particularly if it's not ceramic lined. First thing I'd do is turn it off, hook up a garden hose and drain it, if the water had rust sedimant, then it's possible the galvanized liner is rusting. If you decide to re fill, make sure it is full before you turn it back on.
If you are on a well and don't have a filter, check into one. "Hard" water is very tough on not just the water heater but the rest of your plumbing as well.
It could be just a matter of a bad valve or "vapor" lock. Having just gone through this a little over a month ago, I'm inclined to suspect the heater...I hate plumbing....
My gas water heater started making cracking noises this summer. Indication of calcium buildup..I found a procedure fo cleaning water heaters on the internet. Turn off the gas, drain the heater, and pour in a couple of gallons of CLR through the disconnected inlet. Let it set for about 4 - 5 hours and turn the water back on and start draining. I got loads of fine calcium particles. I drained and refilled about 4 times. The only downside is that for a bout a week the hot water had the faint odor of CLR so I probably wouldn't use it for consumption.
Let's do some diagnostics before we decide - water heater or mixing valve. Either's gonna cost you money, replacing both would cost more.
Get hold of a thermometer that'll measure up to about 140 or 150 degrees F (I assume you don't use Centigrade because of your accent). Go look at the water heater & see if it's got an actual temperature scale on the heat adjustment. If so, make note of the setting. If not, soldier on to Step Two.
Go to your kitchen faucet and turn the water on full hot. Stick the thermometer in the stream, and when it stabilizes at max temperature read the thermometer. If you note a fluctuation in water flow at this point, stop and let us know... unless you have your own pump, in which case you WILL notice a fluctuation in flow in both hot and cold. Note the temperature you read here.
Let the water run for a while, several minutes at least, and watch the temperature like a hawk. Note if the temp fluctuates. If it does, stop all further diagnostics and cast a very strong eye on the water heater.
Now go to your shower (tub / shower, or just shower?) and do the same thing. Full hot, let it stabilize at max temperature, measure the water temp, and note any flow fluctuation.
If there's any question, do the same thing at the laundry. Just open the clothes washer, close the cold-water valve, set it to fill on a full-hot fill, and check the temp. Be sure to turn the cold water valve back on after you read the temp.
If the temperature ONLY fluctuates in the shower, fix the mixing valve. If it fluctuates everywhere, fix the water heater. Probably needs flushing, but might need work on the burners too. The flue might even need cleaning or that the thermostat needs to get changed. There won't be any "elements" in a gas heater - they're an electric-heater phenomenon.
Is the thermometer that you talked about just a regular cooking type of thermometer or is there a special thermometer I need? Obviously I don't want to use a thermometer that is used to check body temperature.
Do you have a tank type hot water heater or a tankless model? A tankless model can have a temp flux if the flow rate exceeds the heating capcity of the water heater especially if you have an anti-scald type valve in your shower. It could mean changing to a lower flow rate shower head, lowering the water heater temp, or the water heater needs to be descaled or cleaned. Just a thought.
The best (and I've found lots of uses for them, so I bought a bunch of 'em for my house & shop) are "test" type thermometers with a metal probe and a round dial. Lacking one of those, you could use a meat thermometer or a candy thermometer or even an outdoor thermometer - anything that can read up to about 140. Ideally the dial shouldn't read much above about 150, so you don't lose accuracy by having too much top end. Probably a meat thermometer would be the best "kitchen" tool to use if you don't have anything better.
You can usually get the better "test" thermometers at auto parts houses and plumbing / heating parts places. Maybe an industrial supply. As soon as you get your hands on one or more, the uses you'll find for it'll multiply like rabbits. :)