Question about Rheem EcoSense by 7.4 GPM Tankless Water Heater Natural Gas High Altitude

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We are trying to install a rheem tankless water heater. We are having trouble finding the flexible gas line. In the instructions it says a 3/4 inch line, we can find a line with a 3/4 connector but the line is smaller. Is there a line that is 3/4 inch or is it talking about the connector ends?

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Rheem warranty does not allow flex connector only hard gas pipe..also gas line should be properly sized to make sure there is enough volume of gas to the unit. Most unit fire at 199,000 btu and if your gas meter is more than 20 ft away and you have more than 1 gas appliance on the line there can be problems with firing if more than one appliance try to fire.. So you should have a qualified technician check before install..

Posted on Aug 08, 2010

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They do make a 3/4 inch flex. You may need to go to a plumbing wholesale outlet to find one.

Posted on Apr 29, 2010


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1 Answer

Can i use the pipe ihad for my 40 gallon hot water heater

If you had a tank-type heater, and installed tankless, then you cannot use the same gas line pipe. You must have 1" gas line running to within 10' of tankless unit, and then 3/4" to tankless... and you cannot use flexible gas line.
You can use same hot and cold water pipes, but install service valves so you can delime the heat exchanger each year.


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Mar 21, 2015 | Rheem RTG20169DVG Tankless Pipe Cover

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I installed a tankless hot water 3 or 4 months ago , now i'm getting a error code 12

Meter has to be sized to meet need of all gas appliances in home.
Gas line to tankless should be straight from gas meter 1" up to within 10' of heater, and then 3/4" solid pipe as you have.
Call manufacturer for qualified technician in area.
Don't install tankless water heaters ... opinion based on answering questions online.


Nov 14, 2013 | Water Heaters

1 Answer

I have a ecosense tankless water heater #rtg-74pvn-2 how far can i take the vent

Feb 2013
1) Rheem/EcoSense tankless product manual does not have specifications for length. Error 11 will let you know if venting is improper.
Often, tankless are installed outside because unobstructed venting is key for combustion of the amount of gas coming out of 3/4" gas line.

2) Copy following link for Bradford White venting: Exactly same as Rheem, but more installation detail. No maximum lengths given.
For lengths greater than 5 feet, a condensate trap must be installed. Acidic water from hydrocarbon combustion will damage metal, and destroy heat exchanger inside tankless if water drips back into unit.

3) Copy following link for tank-type power vent tables:
Generally, the longer distance requires larger vent diameter, and there is max number of elbows and/or air-flow restrictions.

4) Otherwise call Rheem/EcoSense, and add comment saying what resources they offer.

Mar 06, 2013 | Water Heaters

1 Answer

Rtg74pvn2 rheem tankless water heater gas problem

1) You want the truth: Forget tankless.
There are many tankless water heaters with insoluble problems.
And endless problems.
Rheem knows it.

2) Do you really expect your home computer to work flawless after replacing motherboard?
Get your money back from Rheem, or get a full replacement.

3) OR fix water heater yourself today: Install tank-type gas water heater for $350 from local box store.
FYI: Do not buy Rheem, Richmond, Ruud, GE as these units from Rheem have problems that require service technicians.
Instead buy Whirlpool, American, State, Craftmaster, Reliance, Kenmore, as these units from AO Smith have fewer problems and can be repaired by homeowner using simple part replacement.

4) Copy following link for troubleshoot resources, and possible manual for Rheem, Richmond, Paloma water heaters:

Oct 16, 2012 | Rheem RTG-74PVN-2 Natural Gas Pronto Whole...

1 Answer

The instructions on my Richmond tankless water heater talk about cleaning a water filter but give info on where it is or how to remove it I have a rmtgl74pvn

The manual may be suggesting that you clean in-line water filter installed before tankless unit.
Tankless might also have a screen filter where water enters unit.
Open following link for troubleshooting resources:

Contact Rheem:

Jul 04, 2011 | Rheem RTG-74PVN-2 Natural Gas Pronto Whole...

2 Answers

My Rheem RTG-53DVN Direct Vent Natural Gas Tankless Water Heater gets an 11 error code when it sees demand. The manual suggests turning on the gas valve all the way. There is a 3/4" dedicated gas...

Natural gas has a lower pressure/flow rate than propane so through a 3/4" pipe you may not be getting enough at the unit to fire it correctly.
Check that the pipe sizing is correct for the hourly gas consumption of that unit

Mar 06, 2011 | Rheem RTG-53DVN Direct Vent Natural Gas...

1 Answer

What size recomended the gas pipe for rheem ecosense by 7.4GPM oytdoor tankless water heater

1/2 inch if you are using steel pipe (which is the most hearty for outdoor installations).

Happy installation:)

Aug 22, 2010 | Rheem EcoSense by 7.4 GPM Outdoor...

2 Answers

Rheem tankless water heater wont lite

the system was not sized properly, you need to have a 3/4 gas line to the unit for the volume of gas it needs, the tankless water heaters need to have every bit of gas that is says, it sounds like who ever installed di not make sure you had enough gas comming in the house, you might have to either have a new meter installed or run the gas lind directly from the meter to the water heater and cap off the gas line thats there

May 05, 2009 | Rheem Tankless Hot Water Heater...

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