Fresh Water Tank Empties When on City Water

[Brian R.]

Hi,


To my surprise I've discovered that when I'm hooked up to city water that if I have water in my fresh water tank then that's what used first. In other words, the fresh water tank empties when hooked up to city water. Is this typical? I would have thought that when hooked up to city water that no water from the fresh water tank would be used. Once the fresh water tank is empty I'm getting city water at the faucets just fine.



Yes, I am running the pump when on city water. I need to do that to get hot water at the galley sink--otherwise I don't have enough pressure.

[azflycaster]

The water pump only pulls water from the fresh water tank. If you hear the pump, your tank is getting emptied. The pump will operate (when turned on) when the pressure in the system is below limit of the pump pressure switch.

You should not have to turn the pump on when connected to city water. Either your city water pressure is low or something is restricting the flow.

[OTRA15]

Originally Posted by Brian R.

Hi,

To my surprise I've discovered that when I'm hooked up to city water that if I have water in my fresh water tank then that's what used first. In other words, the fresh water tank empties when hooked up to city water. Is this typical? I would have thought that when hooked up to city water that no water from the fresh water tank would be used. Once the fresh water tank is empty I'm getting city water at the faucets just fine.

Yes, I am running the pump when on city water. I need to do that to get hot water at the galley sink--otherwise I don't have enough pressure.

Following up on the last post . . . yes, something is probably amiss with your hot water supply line to the kitchen faucet.
Aerator filter at faucet clogged? Is hot water OK to bath sink, shower, and exterior shower?

If all your faucets/showers have hot water problems, then maybe the mixing/tempering valve at the water heater is clogged with debris, or failing? "Mixing valve debris clogged site:airforums.com" search results may lead the way to a solution IMO:

https://www.google.com/search?q=mixi...=airforums.com

Good luck,

Peter

[Brian R.]

This is a brand new trailer, so I wouldn't expect any debris clogging in the system.



Water pressure and hot water are fine at the shower head and bathroom sink. I have an on-demand water heater--no hot water tank. Without the pump on there is inadequate water flow at the galley sink to activate the hot water heater. When the pump is on it's fine, even when the fresh water tank is empty.

[OTRA15]

Thanks, I would try messing around with the mixing valve as much as is possible in your model. Is there an "on" and "off" and middle range? Do you also have a separate tempering valve which prevents scalding hot water from reaching a faucet? Not sure about your setup, but suggest messing around with any adjustable valves.

Have you removed the aerator on the kitchen faucet to check for debris in there, per the earlier post?

[Wazbro]

Originally Posted by Brian R.

When the pump is on it's fine, even when the fresh water tank is empty.

This sounds a bit strange that it's still fine when tank is empty.
The water pump can only get water to pump from the fresh water tank.

[Brian R.]

Originally Posted by OTRA15

Thanks, I would try messing around with the mixing valve as much as is possible in your model.

Does a tankless on-demand water heater even have a mixing valve?

[OTRA15]

Originally Posted by OTRA15

. .
Not sure about your setup, but suggest messing around with any adjustable valves.

Have you removed the aerator on the kitchen faucet to check for debris in there, per the earlier post?

[guskmg]

Tankless water heaters require a minimum water flow through them to light the burner. Measure your faucet's flow by timing the volume of output for a minute to check GPM flow rate. Then, if low check your system for restrictions in the hot water pex from the kitchen feed "T" through to the aerator. I had similar troubles and it was a clogged aerator, but it could be a clogged line or fitting. If that is the case, use at a blue filter (Camco) when on city water and/or filling the fresh water tank. That will prevent the problem. If your heater works at the other faucets, it is OK.
guskmg

[OTRA15]

Great advice . . .

Brian, did you have a chance to check the aerator on your kitchen faucet?

Cheers,

Peter

[PatsBambi]

Check that all your Valves are wide open. Low point valves should be completely closed.

[OTRA15]

Originally Posted by Brian R.

Does a tankless on-demand water heater even have a mixing valve?

How about that aerator?

[Tif]

Originally Posted by Brian R.

This is a brand new trailer, so I wouldn't expect any debris clogging in the system.



Water pressure and hot water are fine at the shower head and bathroom sink. I have an on-demand water heater--no hot water tank. Without the pump on there is inadequate water flow at the galley sink to activate the hot water heater. When the pump is on it's fine, even when the fresh water tank is empty.

It's a mystery for me too with it only having inadequate pressure with my kitchen sink causing the water not to heat with my on call hot water... my resolve is turning on tbe hot water in the kitchen & leaving it on while I turn on tbe hot water in the kitchen because it triggers the heating element to come on & VOILA! I turn tbe water off in tbe bathroom once it's hot in tbe kitchen & also wait for it to be hot in the bathroom before turning it on in tbe kitchen- that way I know it already turned on my on demand water heating element

[Boxite]

I wonder if your outside shower hot/cold faucets are fully closed?

[Mollysdad]

Do you have a puddle on the ground? I'd start there.

[JBamadon]

Welcome to the new world of a Girard Tankless water heater. Do a search on "tankless" and lots of threads pop up.
You need good flow to trip the flow control sensor in the Girard. My observation is this equates to about 40 psi water pressure or better in our 2023 FC27 with a single spigot turned on. Most campgrounds seem to run about 20-30ish psi pressure. Our pump is adjusted to run at its max of 50ish psi. Its an easy adjustment to make yourself. We run with the pump on always so as to get pressure/flow=hot water. The pump will pull water from the tank to "make up" for low flow from the city supply side.
Try adjusting your pump.