Question about Rheem Tankless Water Heater Manifold Control Box

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How can you adjust the dip switches on the Rheem Tankless hot water heater RTG-74XN?

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Here is the link to the service manual for your tankless water heater:

See page 35 for specifics regarding dip switch settings. If you have problems with the link, post again and I will publish it on my company website for you to review.

Richard Johnson

Posted on Aug 22, 2009


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Need repair and diagnosis
Fix any tankless problem quickly yourself today for $380... and install tank-type heater:
Don't buy tankless... don't buy Rheem products... seriously now.


Jan 23, 2014 | Rheem Tankless Water Heater RTG-74XN-1,...

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What can cause Hot/Cold spikes on an RTG74-XN

Crossover, low hot water flow, low water pressure, sediment in water lines or heater, heat exchanger needs to be de-limed, water filter needs to be cleaned, water heater temperature set too high, incoming water temperature too high or too low depending on model, MUD or PUD districts with pressure spikes, dirty faucet aerators, loose wires, bad sensor, faulty PD-board, bad venting, dirty burner and combustion parts, etc.

Clean water filter monthly, de-lime tankless yearly
No error code:
Overcoming fluctuating temperatures:

Sep 20, 2011 | Rheem Paloma PTG-74XN / RTG-74XN Natural...

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Before calling service technician, open following links for Rheem troubleshooting resources:
C2 11 is no ignition:

Tankless water heater should have yearly maintenance that includes cleaning burner parts, with check of ignition parts, wiring, ignition sequence, gas supply, and bleed gas line if needed.
Chances are that your unit needs to catch up on maintenance.
Maintenance can also catch any condensation problems and make venting adjustments so parts are not degraded due to vent issues.
Tankless should also be delimed each year to preserve efficiency of heat exchanger.

Jun 29, 2011 | Rheem Tankless Water Heater RTG-74XN-1,...

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RTG-74XN2 won't put out hot water until about 9am.

Tankless questions are complicated because these units have many parts, and both internal and external issues can cause problems. Also problems can arise from combination of issues including maintenance, incoming water temperature, pressure, air quality, venting, water quality, water pressure, in addition to internal washers, gaskets, and parts functioning perfectly with each other over time.

Hot water only after a certain time of day indicates problem might be pressure related.
Which could be local water supply, or clog in line, or sediment on pressure sensor, failed pressure sensor, dirty in-line sediment filter, improper vent, or combination of things listed.

Rheem suggests calling service technician.
Service technicians train for years on one brand of tankless, and then see something new each day.
To understand why service technician is recommended, view number of UNanswered questions on following link showing one Rheem tankless model number.

I suggest avoiding tankless water heaters since all costs are energy.

Clogged pressure sensor after 2 years exposure to hard water. De-liming tankless will not prevent failure from hard water.

Add a comment for more free help.
Also take advantage of fixya expert assistance live.
For a price, expert works with you via e-mail while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Feb 21, 2011 | Rheem Paloma PTG-74XN / RTG-74XN Natural...

1 Answer

Rheem tankless rtg 74pvn - heater hot water shuts

This is something you will have to contact rheem about due to the fact you don't have a fault code

Jul 13, 2010 | Rheem Tankless Hot Water Heater...

1 Answer

I have a Rheem tankless pronto unit. I had a

is there any type of surge portection for tankless water heaters mother boards??????

Mar 06, 2010 | Rheem Tankless Hot Water Heater...

2 Answers

My Rheem Tankless Hot Water Heater is installed, but is it not attempting to start. The digital display keeps blinking 82, 0, 82 , 0 ...?

If this is a new board and Altidude chip with power on set dip switch 1 and 2 to on. Then press and hold adjust button until on board blinks fast then and you will see dashes on LCD display. Set dip switches 1 and 2 back to off. Turn on remote unit and you should see 100F. With any luck you are good to go.

May 02, 2009 | Rheem Tankless Hot Water Heater...

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