The hot water mystery

[Orca]

I have a 2021 Forest River Flagstaff super light 26FKBS. When we first got it hot water seem to last long enough to take a semi-decent shower. Last three or four days not doing that. Running out of hot water and what seems to be a very fast period of time. This happens on both electric and gas heat. I know it’s only 6 gallons but I figure if the electric has been on all night it should give me 6 gallons of hot water, it’s not. If anybody’s run into the same situation love to have some input. We’re relative newbies.

[aceinspp]

One, this its not like taking a shower at home. You have to be conservative and that being turn on water get wet. Turn off soap down then turn on to rinse. Also air temp plays into this also if it turns colder from the first days camping. 6 gals does not go far if one ust lets it run like you taking a shower at home. Later RJD

[KyDan]

What is the in-coming water temp now compared to "when you first got it?"
You can use both electric and LP gas AT THE SAME TIME. This will cut the time to heat down by 2/3.
A sudden change in perceived hot water capacity could be simply the outside water coming in is colder.

[JMark]

what ace said...I have the same unit and no issue with enough hot water. are you running electric only? If so may be an issue with element. If running on gas should be OK.

[Semperfi24]

Dont forget that every ounce of hot water that leaves the tank is replaced with an ounce of cold water.

I am just making up numbers to illustrate my point, none of the following is scientific in any way. Lets say you have 6 gallons of water in the water heater, and the water temp is 135 degrees. If you turn on the hot water and fill a one gallon bucket, you have now replaced a gallon of 135 degree water with a gallon of 50 degree water (or colder). That will drop the 6 gallons down to (again, making it up) 120 degrees. Now dump another gallon of hot, which is replaced with another gallon of cold. Now you have 6 gallons of water that is 105 degrees... I made those numbers up, because I dont know what the exact measurement is, but that is the gist of how it works. The same thing happens to me at home. If I turn on the hot water in my basement bathroom (water heater is on the other side of the wall down there, so I can actually hear it), around the time that the water starts coming out of the faucet hot, I hear the water heater kick on (its a gas water heater). The reason I hear it kick on is because hot water has left the tank, probably a half gallon of water (maybe less), which was replaced by cold water, and that half gallon of cold water is enough to lower the temp of the entire tank (80 gallons) for the thermostat to tell it to fire up to heat the water. If that happens at home with an 80 gallon tank, imagine how dramatic it will be when you shrink the tank to 6 gallons.

[ependydad]

Check to make sure you're not mixing cold water into the hot water stream.

1, check your outdoor shower and make sure the knobs are off.

2, check your winterization valves and make sure they're all fully turned.

If you're mixing cold water into the stream, it will present with hot to warm water to start that quickly gets cooler.

[tomkatb]

For new persons!

Has a low flow shower head been installed?

Are you turning on both the gas and electric heating systems. Recovers much faster.

6 gallons is not a lot. You have to conserve. A lot.

Hot and cold water can leak thru valves slightly open. We had noticed less hot water. It was me. I got into the habit of turning the shower off with the shower head button. (Old head)That allows hot and cold to mix.

The new head dribbles when turned off with the button. Keeps temps warmer. No cold shots. Makes you turn the valve off properly.

[kayakist]

Originally Posted by tomkatb

For new persons!

Are you turning on both the gas and electric heating systems. Recovers much faster.

As a newbie, thank you for this. Once the heater reaches desired temp do you leave both systems on or turn one off (which one). Thanks,

[tomkatb]

What we do is turn the electric on when the shore power is available. When the DW and I want long showers, or we have guests, we turn the gas on. It is a switch in the rv panel. Then turn it off when we think of it.

I suspect leaving both on full time would not matter.

Gas only is faster than electric.

[SlowrideHD]

All good advice but what immediately comes to mind is that your "winterize" valves are still set in the bypass position. Make sure they are correct first thing. Then, as others have said, turn on the propane for quicker recovery and take a Navy shower (wet down, soap up, rinse off).

[Reverse_snowbird]

Originally Posted by kayakist

As a newbie, thank you for this. Once the heater reaches desired temp do you leave both systems on or turn one off (which one). Thanks,

We left both on....unless you have a low supply of propane.

[SmackIt]

I recently had a similar thread, it may give you some insight.

https://www.forestriverforums.com/fo...er-219998.html

[AntonJ]

x2 slowridehd. That's what happened to me.

[John 2019 SS 3010DSF]

You can use gas & electric at the same time. I leave the electric on and just before I jump in the shower, I turn the gas on. I don't run out of hot water during my normal shower. After my shower, I turn the gas off.

[rracer5]

Originally Posted by ependydad

Check to make sure you're not mixing cold water into the hot water stream.

1, check your outdoor shower and make sure the knobs are off.

2, check your winterization valves and make sure they're all fully turned.

If you're mixing cold water into the stream, it will present with hot to warm water to start that quickly gets cooler.

X2, this the most commonly overlooked solution.

[tgold]

If you’re latter trips were in cooler weather rather than summertime or if you get very cold water from the source your hot water will not last as long. As soon as you use one gallon of 120 degree water from the water heater it is replaced with much colder water. The mire cold water mixed in with a diminished hot water quickly cools your six gallon tank to barely warm water. Use both electric and propane turned on just before showing and extend your warm water via a quicker recovery. Still six gallons usually means water on to get wet then off at shower head valve, soap up then water on to rinse. Or with electric and propane on allow about 15 minutes between showers to allow the water heater to recover.

[kayakist]

Thanks for answering my question, this is a good thread, I've learned a lot.

[Eagle-751]

You guys should look into the tankless heaters, if you do, you will never go back to a water tank. I can shower all day long and the temp never changes. Trust me, if you get one, you will wish you did it years ago.

[SmackIt]

Originally Posted by Eagle-751

You guys should look into the tankless heaters, if you do, you will never go back to a water tank. I can shower all day long and the temp never changes. Trust me, if you get one, you will wish you did it years ago.

I've heard very different opinions from people that aren't using hook ups. If you're constantly turning the flow of water on and off while taking a "Navy Shower" the tankless are not very good due to constant temperature changes.

[nomad297]

Originally Posted by SmackIt

I've heard very different opinions from people that aren't using hook ups. If you're constantly turning the flow of water on and off while taking a "Navy Shower" the tankless are not very good due to constant temperature changes.

The temperature-changes you mention are what we in the plumbing industry refer to as “cold water sandwiches”. The “sandwich” of cold water between two sections of hot water occurs when the flow is stopped or slowed down enough to deactivate the flow sensor which will tell the gas control valve to turn the flame off. When the flow sensor notices flow, it takes a second or two...or three for it to tell the gas control valve to fire and create hot water again. So, you are left with a section of hot water in the pipe between your shower head and the flow sensor when the flow is insufficient, followed by a seconds-long portion of cold water after the flow is sufficient and the flow sensor has been activated, followed by the hot water again.

What I just described is the case with most basic tankless water heater installations, but it can be resolved a couple of different ways. Truma’s AquaGo Comfort Plus water heater has a built-in recirculating system to combat the cold water sandwich — their standard AquaGo Comfort does not. Here’s a diagram of the two different setups:



Bruce