Rinnai Tankless help

[IAm_Not_Lost]

Hey all,
New build home, owner builder. just installed the tankless hot water heater and I am getting luke warm, but not hot water.

Its a Rinnai V75iP.
Propane unit that has a proper 3/4 inch propane line, properly set up with correct second stage pressure and a very short line run. The water inlet is from a 3/4” pex supply line that comes from my well and pressure tank that is 100’ feet away. Pressure on the pressure tank is set at a standard 40-60psi. I am using the proper Rinnai vent tube that they sell.

I have 3/4” pex going from water heater and going to main areas of house where 1/2” tees off as needed for fixtures.

The problem is that I can’t get the water more than luke warm. Temp was at 120, so I moved it up to 140 just as a trial, and it does get a little better, but not great. No error codes.

I have read all I can but I am not seeing a clear answer. As far as I can tell everything is setup as it should be. Any experts out there have a differential problem list that I could start working through? I would really appreciate it.

 

[Breplum]

I quit working on Rinnai but basic tankless protocol is you need a manometer, a way to measure temp of the hot piping and , pathetically need a remote to do any troubleshooting.
I love Navien because all troubleshooting is built in to every unit. Maybe higher eff. Rinnai do have that.
Are we getting the rated delta T. at rated flow?
Rinnai tech desk is likely the way to go once you have your test equipment ready.

 

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[JustWantHotWater]

Throwing darts at the wall …

What’s your altitude? There are altitude settings that may help.

Are you sure you have the propane version? Check the settings to reflect that they state propane too. Saw a YouTube where a guy thought he had natural gas - box and manuals all were natural gas - but the internal settings were all propane. Maybe it was the other way around - but you get the point.