What if no fresh water for HW heater?

[rce]

Wondering what if my fresh water tank runs dry (and not connected to city water) will my hot water tank eventually run low or dry? If connected to 120 V and water pump on will I eventually fry the element?

I ask because last time camping someone stole my fresh water tank cap and I was out of water and didn't notice as I was just leaving for home. Water heater was off but what if it had been on?

Only noticed when I got home but possibly could have been running the hot water taps with pump on and not realize I was out of wate and then would that drain the H/W tank??? Any different if I was using propane to heat the tank?

(Actually at home first thought my pump was not working as I had filled the tank, I thought, and water pump wouldn't shut off)

Suburban H/W tank if that matters. Thanks for any info/advice

[aiscpl6]

I would guess that once the fresh water tank is out of water you lose water pressure so water in the H\W tank would stay there or most all of it anyway...

[rce]

Originally Posted by aiscpl6

I would guess that once the fresh water tank is out of water you lose water pressure so water in the H\W tank would stay there or most all of it anyway...

Hope that's right. Makes sense if the pump comes before the H/W tank. If after it would just suck it dry I imagine. Will have to take the inside panel off I guess and make sure of the series?

(Still struggling a bit to understand the flow of things in the water/plumbing system but getting there)

[aiscpl6]

The pump is close to the fresh water tank and pushes water from there to where ever it needs to go like a water pump in a well pushing water to a house except the pump in your trailer is not submersible. My pump is in the rear of the trailer in the bathroom beside the tub, there is a little access hatch to it on the side of the tub.

[rce]

Originally Posted by aiscpl6

The pump is close to the fresh water tank and pushes water from there to where ever it needs to go like a water pump in a well pushing water to a house except the pump in your trailer is not submersible. My pump is in the rear of the trailer in the bathroom beside the tub, there is a little access hatch to it on the side of the tub.

Having had a cistern for 20+ years and water pump for the house I really like the analogy to a water pump in a well! Helps me wrap my head around it much better.

Now I'm thinking (guessing?) as long as the H/W tank water doesn't drain backwards through the water pump there should always be water in the H/W tank as long as you don't drain it yourself? I'm assuming there is some sort of check valve to prevent that?

[aiscpl6]

I think so, I filled up my H\W tank about a month ago to test it and then drained the fresh water tank but not the H\W tank. Last weekend when we went camping I filled the fresh water tank up and turned the water pump on to make sure the H\W tank was full as it holds 6 gallons and I wanted it full before I left the filling station and it was still full.

[Herk7769]

Originally Posted by rce

I'm assuming there is some sort of check valve to prevent that?

Yes, an it is located inside the pump housing. It also prevents city water pressure from filling your fresh water tank.
Herk

[RamblerGuy]

There is also a check valve on the city water line that prevents your water pump from pumping your water out the city water connection.