Hot water shuts off at random times.

When is the last time it was flushed?

Hi,
This has to be one of two problems....
Either the dip tube is not in place properly or the hot and cold are reversed....
That is the ONLY way that you can be having that problem....

Make sure you have another person look at the heater...
Take off the piping on both the hot and cold lines and VERIFY that the dip tube is in place in the cold side, and that there is NO dip tube in the hot side....then also that the pipes are connected correctly...

heatman101

I had the EXACT same problem (installed my tankless last winter and worked fine, now this summer it fluctuates, have to turn the shower completely off and then on again to get any hot water and then it only lasts for a couple of minutes!) Argh - it is frustrating!

Here's what I found: the demand for hot water is lower during the summer (hot) months because the "cold" water coming in is already quite warm. You don't need as much hot water to make the shower temp comfortable. SO, my tankless was shutting off due to low flow demand. I've removed the flow restrictor from my shower head and it helped alot but didn't completely solve the prob. Next step is what has been recommended to me by several people but is much more expensive - change the pressure valve on your shower to a temperature valve. Or just wait til winter and it should work ok again :)

A 40 gal. electric water heater will give you aprox. 32 gal. of hot water in one setting, since they do not reheat as quickly as gas. So if you are using a newer 1.5 or 2.0 gpm shower head. You could take a 16 minute shower with straight hot water. If you are running 2 new shower heads at once you could get 8 minutes. If you using the tub spout the times decrease. Some of my customers like to turn up the temerature on the thermostat a little so they can mix more cold and get it to last a little longer. Be very careful doing this.
If your water heater has a lot of calcium built up in it the times will decrease.
With out seeing the heater, you mention it is a mobile home heater so I am guessing that it is bottom fed.
I hope this has helped.

turn the water flow off and control off and hold the two arrow buttons together
then use the up arrow to get to e and the down arrow to get to 1 what do you see?

have you checked the error codes on the heater?
you can do this by powering off the controler and pressing the up and down keys for a few seconds. this should take you into the diagnostics mode scroll using the up and down keys till you find the one that has the letter E on it and that will give you the last 8 error codes write them down and get back to me

it is because the tub has a temp control valve in it so if you were to put more cold with the hot it will last longer but still won't be all the way hot,, now a days people are suing the manifacture because they are getting burned form the hot water so they put these saftey temp controls in place of the old style 2 or 3 handle faucets,, there fo no more real hot water nothing you can do outside of change to the othere type of faucet 2 or 3 handle tub shower diverter,, that why the water is hot in the sink but not the tub.....

if your heater is near the ten year mark, thats signs of going bad.....

check the screen on the cold water intake on the cold side,, you might have to flush the system out, and do you have the shower head water restricter in, if not you may be using to much hot water,,, how many other hot water fixtures are running at the same time? try running just the shower,,,if this is a tank water heater the dip tube could be bad that is on the cold side it takes the cold water to the bottom of the tank and forces the hot water out,, if you ar only getting a couple of min of hot water and the dip tube is bad it is not going to the bottom but just at the top and not getting all the hot water you will need a plumber

what is it doing, I would first check the inlet water screen and make sure that it's clean. shut off the water going to the unit and the screen is right after the shut off, unscrew it and clean it. replace and turn the water back on. you can ask for me again if this does not help