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tankless hot water heater

gracejustice Member Posts: 1
I purchased a Rinnai RL75i tankless hot water heater it was installed in the basement. I live in a 1000 SF 2 story duplex. The hot water reaches the kitchen sink on the first floor but not the powder room sink on the first floor . The hot water reaches the shower on the second floor but not the 2 sinks on the second floor. The water flow requirement for the Rinnai is .5. The faucets have water flow of 1.5. However we have been told that the reason the hot water does not reach the sinks is because there is not enough water pressure in those faucets.
We have been told that if we want to get hot water to the 3 sinks we have to get faucets that are 2.0 or upgrade the Rinnai tankless (for a lot more money).
We just remodeled and have not even used these new faucets (not cheap) for a month! And what if we buy them and the hot water still does not work?
Is there any way to create more water flow in the faucets that we have?
I dont understand why this Rinnai does not work!
So far we have been told that our options are 1. get 3 new faucets (I am not sure if this would even work). 2. Upgrade the Rinnai plus some kind of pump (another $1,800) or have it all taken out and get a standard water heater tank.
Can anyone help with this?


  • Harvey Ramer
    Harvey Ramer Member Posts: 2,239
    Certainly. Unscrew the screen/aerator on your faucet outlet. Inside you'll likely find a flow restrictor, a little plastic plate with 3 or 4 pinholes in it. Remove it and reinstall the assembly. You'll have more flow and hopefully it will activate the water heater.
  • gschallert
    gschallert Member Posts: 170
    As Harvey said, check to make sure you don't have a low flow aerator but the specs on that model indicate it will fire with .4gpm flow. I'd also measure the flow rate to verify and make sure there's no flow restriction from scale in the valve body or shut off valve. A standard residential lavatory faucet should have no problem getting that unit to fire. Are you municipal water supply or well with pressure tank?

    LOL, somebody actually told you that you had to upgrade the unit or replace it with a tank?
  • lchmb
    lchmb Member Posts: 2,997
    http://www.taco-hvac.com/products/systems/instant_hot_water/genie/index.html here's another thought to add to the mix once you remove the flow restriction
  • Big Ed_4
    Big Ed_4 Member Posts: 2,805
    Yes pop the restrictors ... I am sure that will work ...............You can also install small tank HWH in series for the low volume bathroom sinks..

    There was an error rendering this rich post.

  • kcopp
    kcopp Member Posts: 4,440
    Another possibility is that is the piping in the home is a bit older corrosion from inside the piping that may have fallen off the inside of the piping when the water was shut off. It then would have made its way to the faucets w/ restricted flow and plugged up the aerators/ flow restrictors.
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,331
    Hello, Neoperl; http://www.neoperl.com/default.aspx makes nearly all the aerators for everybody. They make fixed orifice and pressure compensating types in a number of flow ranges. They are cheap too! I'd get some pressure compensating types with different flows and see what worked best for you.

    Yours, Larry
  • Jack
    Jack Member Posts: 1,047
    You do not need to upgrade the Rinnai. That is ridiculous! That is the same model I have in my home and I do not have the same issues you are having. What temp do you have the unit set at. It is not uncommon when you don't have enough hot water, and are used to a tank that you turn the water temp up. If you have done that with the tankless you are reducing the mix of hot/cold to arrive at your comfortable use temp. Set the unit at 120. Removing the flow restrictors may be necessary.
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    Also, check the filter on the Rinnai to make sure it is not partially blocked. It is on the cold water inlet on the bottom of the unit. Just turn off the water to the heater and unscrew the filter and clean it out. It doesn't take much gunk to slow flow down.
  • bob eck
    bob eck Member Posts: 930
    Do you have hard water? If the heat exchanger is building up with lime from hard water it takes more time for the water to heat up to the set temperature. If this is happening the unit measures incoming water temp and out going water temp if the outgoing water temp let's say is set for 120 degrees F and the unit is not sending out 120 F hot water the unit will slow down the GPM flow rate going through the unit to make sure it is delivering 120 F out going water temp. The same thing can happen with the unit if you are trying to run let's say 2 showers and trying to fill a whirlpool tub all at the same time. In this case the unit will slow down the GPM flow rate to make sure it is delivering the rite outgoing water temp. Most 199,000 BTU input TGWH will deliver about 5 to 5.5 GPM at an 70 degree F temp rise.
    Call a professional plumber or HVAC contractor that knows how to work on TGWH to come out and look at your unit. If the heat exchanger is building up with lime from hard water the heat exchanger will get excessive heat to make hot water and will cause the heat exchanger to fail prematurely early and most TGWH manufactures will not give a warranty on a heat exchanger that has leaked from a build up of lime from hard water. Call in a professional.