Minimum Water Flow

[silverloaf]

Can anyone tell me the water pressure and flow necessary to maintain a consistent flow of hot water. In 1017, as pert of the restoration effort, I replaced all plumbing and fixtures. I also installed an Atwood on-demand water heater.

The heater puts out very hot water. The bathroom sink works great. But the kitchen sink and bathtub are unreliable. I have to turn the bath faucet 3/4 on before getting warm water to the other two.
I’ve tried it with the 12v pump as well as shore water. I have a 45psi pressure limiter for the shore water. In either case, the water to the kitchen sink and bathtub is inconsistent.

I do know the the Atwood heater require a minimum 1.5 gph to activate. I’m beginning to wonder if I have too many pex elbows, tees, etc. I’m beginning to think it’s a combination of marginal pressure and flow.

I thought of repiping some of the long runs in 3/4 pex ( now 1/2). Any input from the voice(s) of experience?

Btw-
We are now living in our camper on-site where our house is being built. We are thoroughly enjoying the features and comfort of this well-built home on wheels.
:

[Razorback]

Our 1987 34W has a pressure regulator that was a stock item on the trailer. Does yours have one?? Maybe one too many regulators? Also, do you have a water filter on the input to the trailer? That could need to be replaced.

[silverloaf]

I installed an after market pressure regulator when I re-did the plumbing. I have a filter for in-coming water. There is no in-trailer filter. I have tons of water coming out of the filter only.

I’ll have to pull some plumbing fittings apart and measure pressure and flow. My gut feeling is that I need to have the plumbing running in parallel rather than series. I might do a 3/4” manifold to keep from starving water supply.

I know it is not uncommon in buildings for pex to require a manifold and parallel tubing runs. More to come sometime later.

[Salty]

One of my neighbors has an Atwood on demand that is 2 years old at this point. Water pressure here throughout the park is at 48psi and he has no issues with his hot water.
My on demand fires at 0.5 gpm, but it isn't an Atwood.
Have you removed the residential water restrictors on the faucets?
I have eliminated the pressure regulator on my trailer, simply b/c it's all PEX. I believe the specs on PEX is 186 psi max at 100 degrees F, 100 psi at 186 degrees F. To that end, I saw no need for a pressure regulator. I would find it difficult to imagine any location where water pressure would exceed 80 psi, let alone 100. I imagine it is possible, but certainly not standard or common. Even in Georgia.

[silverloaf]

We are now on filtered well water with 60+ psi pressure. I’ll try removing the pressure regulator.
Even so, it shouldn’t take 60 psi to get hot water to the shower. I’m going tear things apart after we move into our house. Right now, some hot water is better than pulling thing apart and having no hot water. I would be in hot water with my wife if I did.

[Salty]

Agreed, it shouldn't take 60 psi to fire the water heater. I'd hate to think it was the elbows causing a restriction and reducing flow. it could be that the flow sensor is failing or being impeded. You're likely still under warranty, no?