Atwood water heater not hot

Have you used the outside shower? (#1 cause of this syndrom)

It is possible something has changed.. Atwood water heaters come in a few different ages.. Modern ones use one T-Stat and one ECO.. it may be the T-Stat has wore out and is cutting you off sooner, or some other related change.

NOTE: you can get T-States in other temps (120,130,140 up to I think 180) however goign higher than 120 is not recommended.

Another posibility, Atwood makes a 10 gallon heater that fits in a six gallon hat. How does it work? Simple. I mentioned a 180 T-Stat above, they use that one, heat the water to 180 (near boiling, in fact at this temp you coudl just pour it over yoru coffee grounds as that's in the range of many coffee makers) On the output of the water heater is a thermostatically controlled mixer valve, it adds cold water to bring it DOWN to 120,, Thus giving you about 10 gallons of 120 degree water from a six gallon hot water tank.

I you have this system (and from your description you just might) and that valve failed. (letting too much cold in)... Well.

Could be your bypass valve worked open a little bit (easiest fix) or your check valve on the hot out (top) of the water heater might be going bad. If the check valve is bad it would allow cold water to infiltrate the top of the water heater while at the same time allowing hot to leach out. This would lower the overall temp of the water in the water heater. About a $10 fix if you can get to it.

we have been using the heater since we left home the 24th Nov to come south, we winter in Miami , all wss ok till last couple weeks, Thanks for the reply

When you say used to, how long ago was that, and have you changed and settings, winterized, etc. It is winter and cold is really cold and will take less cold water than say the summer. It is quite possible that during the winter one shower will use most of the available hot water and the cold water going into the wh will dilute what's left. You might try running the wh on gas and see if you have the same problem, and try running them both to reduce the time it takes to replenish the hot for that second showe

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I am in Miami Fl and its been in the 80s and we have been using the water heater since 24th Nov when we came south,><> Thanks for the reply

When you say used to, how long ago was that, and have you changed and settings, winterized, etc. It is winter and cold is really cold and will take less cold water than say the summer. It is quite possible that during the winter one shower will use most of the available hot water and the cold water going into the wh will dilute what's left. You might try running the wh on gas and see if you have the same problem, and try running them both to reduce the time it takes to replenish the hot for that second shower.