Is it normal to see a little water splash out the top of the unit during the Fill process?
Yes.
But, not to worry, it's just a bit of overspray from the fill process...
Keep in mind:
- If your overflow line is connected, there shouldn't be much on top of the heater. Most will drain down the overflow line to wherever you've got it terminated.
-If you're using a leak detector in the pan, you may not want to connect the sensor until the fill process is complete and everything is dry.
-If you notice more than a few ounces, something else might be going on.
-What's happening is: there is some open cell foam in the airgap fitting (where the 3/4" female NPT connector is) - you wouldn't notice it unless you take the black cap off. While the fill valve is open, water is pouring in and taking a sharp turn through that fitting to go down into the tank. It's that high pressure water taking the turn that causes the turbulence and a bit of splashing. The foam is designed to catch most of the overspray, as well as minimize evaporation after the fill process.
Still not satisfied? Additional Questions?
...See Chapter 4, page 21 of the manual or give us a call!