ducktoller
New Member
I have been considering replacing my 50 gallon gas direct vent water heater with a tank less. I have one large soaking tub that never gets fully filled and this has always been an annoyance. There are two showers in the house but one has 4 small Moen Body sprays with one regular shower head. I had a plumber come out and give me a bid and after I reminded him I had 4 body sprays he indicated I would mostly likely need two RU98I Rinnais to keep up with the flow. I wasn't quite ready to pay to have two of them installed so now I am on the fence.
I did some research and some testing on pressures and actual flow rates in my shower. The pressure at the outside faucet which is 3 floors down is 77 PSI so the pressure up at the shower is probably around 66 Psi at the shower head based upon my rough calculations (feel free to correct my assumptions). I also measured the flow rates at the shower head and the body sprays the shower head was putting out about 1.7 GPM and each body spray was putting out about .6 GPM. So the total shower is using about 4.1 GPM .
So looking at the Rinnai specs and the flow curves it seems like a single RU98I would cover it but when I went on the Rinnai website and used the Rinnai tankless sizing calculator it basically said I needed either 4 R98LSi or up to 5 smaller ones! I am assuming the different is due to using rated flow rates for typical shower head and body sprays. But even there it seems like I am missing something.
Am I all Wet?
I did some research and some testing on pressures and actual flow rates in my shower. The pressure at the outside faucet which is 3 floors down is 77 PSI so the pressure up at the shower is probably around 66 Psi at the shower head based upon my rough calculations (feel free to correct my assumptions). I also measured the flow rates at the shower head and the body sprays the shower head was putting out about 1.7 GPM and each body spray was putting out about .6 GPM. So the total shower is using about 4.1 GPM .
So looking at the Rinnai specs and the flow curves it seems like a single RU98I would cover it but when I went on the Rinnai website and used the Rinnai tankless sizing calculator it basically said I needed either 4 R98LSi or up to 5 smaller ones! I am assuming the different is due to using rated flow rates for typical shower head and body sprays. But even there it seems like I am missing something.
Am I all Wet?