Question about Rinnai E75CN Condensing Boiler

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Rinnai E75 always displays FILL

January 2012 - I had a Rinnai E75cn system installed to replace an older Hydrotherm unit and 35g tank. Over the past 6 months it displays FILL quite often, and I have no heat/hot water when it does so. I have tried pressing the "R" button to reset it, and sometimes it works, most times it doesn't. I believe the system is saying it is low on water, and needs to be topped. I just can't find anything to outline these steps in better detail than what the manual says. If this is normal I need to know, if not normal, then something is wrong, and after only 16 months, there shouldn't be anything wrong with it. Other details: There is a flow-restrictor on the main water-in, set to 80psi. Without it, flow was over 120psi, too much for the system, so I was told. An Aqua-Pure water filter was also installed, prior to the flow-restrictor, and I change the filter on a regular basis, when it looks dirty.

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I'm sure you've resolved this by now! However, for anyone else looking, with any boiler changeout it seems to disturb any sediment that may have been in piping for some time for many reasons.Also, excess solder or flux chunks can create havoc. Any valves, restricters, prv can get gunked up in the process. Usually it gets stuck slightly open. Some have screens that get clogged as well.

Posted on Nov 05, 2013

  • Ricka182 Nov 06, 2013

    I wound up calling the installer back.. He called Rinnai. They came to the conclusion of a very small leak from behind the foam insulator was causing the pressure to drop over and over. It would drop due to the leak, then eventually fill up again after multiple reset cycles, then drop again. Due to the heat, it was pretty much evaporating, sans a little bit that dried on the copper below, so I never woul dhave seen it. It's been working like a charm since then, no issues. Thanks.



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SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
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Posted on Jan 02, 2017

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SOURCE: Rinnai 556F stuck on Low and will not produce heat

The Low code indicates that the heater did not start because of lack of gas or that the flame rod did not sense enough heat. Make sure all gas valves are on and if you use propane gas, that it has gas in the tank.

Assuming all gas is on, you will need to remove the front cover by first pulling off the very bottom trim piece. This is located below the louvers and by grasping both left and right sides of this trim, pull toward you. It is just held in place by little clips. Now taking a very new #2 Philips head screwdriver, remove 2 screws found on the extreme left louvered section of the front. Then 2 more on the extreme right. Two more near the center of the louvers. Now I think there are two more holding the bottom in. Gently move back and forth the front panel starting at the bottom and work out the clips at the top just below the instrument area. Be careful to not break any of the clips at the top. With the front off, at about the 5 o'clock position you will see a very small round hole with glass over it. Start the heater and look to see if it ignites and stays on for a second or two. If it does but goes out very quickly, you may have a corroded flame sensor. The flame sensor is located by looking into the small hole and up to the 11 o'clock position. All it is is a probe that sticks down. The only way to get to it is by removing the small window section of the heater and use a wire brush used to clean a gun and brush it. Or very gently take a thin but long regular screwdriver and scrape off the probe. Be careful not to damage the fragile white gasket when taking off the sight port.

If the heater never started, you have a restriction in the gas train. Typically I find that spiders make a nest inside the gas burner because the bugs they eat likes the gas smell. The only way to get to their web is to remove the burner from the unit and clean it. This is not an easy part to remove and suggest you call a technician.

Good Luck!

Posted on Nov 04, 2007

  • 1420 Answers

SOURCE: Ductless heater shutting down

There is a small wiring harness that goes from the main board down to the sparker board at the very bottom of the heater. Disconnect this harness and reconnect making sure all pins and contacts make good connection. If it continues, replace the wire harness. Also make sure the outlet that the heater is plugged into is a grounded outlet. Stray voltage can interrupt the thinking of this unit.

If all connections are good and the unit is grounded, you are probably looking at replacing the sparker board. I do have these parts and would be more than happy to send them to you for a donation.

Posted on Jan 18, 2008

  • 330 Answers

SOURCE: Rinnai Infinity instant hot water

call the installer back

Posted on Jul 03, 2008

  • 1420 Answers

SOURCE: Max temperature for Rinnai 556WT restricted to 74 degrees

There is no way to restrict the setting and keep it UL approved. If you cannot get the heater above a certain setting you have either too small of a heater, too much outside air entering the apartment or the gas pressures are not great enough.

Posted on Feb 20, 2009

  • 1420 Answers

SOURCE: My Rinnai says not to use it without an air filter

If you have a RHFE263, 431 or 556, the air filter is located at the top in the seam where the wall trim piece attaches to the heater. It looks like a dryer lint filter.

Posted on Feb 15, 2010

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