Eternal water heater repair question

[Ron7]

My eternal 145 has been getting finicky-starting a shower fine, then going cool after a few minutes for just a minute or two, then back to the original temp for the rest of the shower.
Now all of a sudden it’ll heat the tank on standby fine, but won’t burn hard enough to keep up at normal flows. I have to turn it up all the way for a shower that’s just luke warm and have to slow down the flow to fill a tub that’s only warm.
No error codes at all and the manual isn’t much help without a code. Any ideas from the pro’s?

 

[Sproutnik]

Bad flow sensor?

 

[Sponsor]

 

[Sproutnik]

After checking the reviews on Amazon for the Eternal 145, I feel for you, buddy! Based on what folks are complaining about in those reviews, it sounds like it could be a problem with the heat exchanger -- folks mentioned that the heat exchanger can crack, and I wonder if that's the type of failure that wouldn't throw a code.

 

[Plumber69]

Maybe dirty flame sensor. I came across a similar problem with the same unit but it gave an error code. I suggest having one person at the tank and other at the shower. run the shower while on the phone... when it gets cold see what the tank is doing. Take the cover off

 

[Work it!]

FIXED my GU100 Eternal tankless, bought in 2014. Its only been a day but this is more than I could find online to fix it.
Lost hot water recently and found E27 error on the front panel. Found out that the company went belly up and so on. Opened it up and it was totally dry inside and according to the error code there was a problem with the mixing valve initializing. Saw a video on Youtube about this and followed the directions to remove the mixing valve assy. It's the white plastic thing with two wiring harnesses attached to the bottom of the gray plastick mixing valve. Easy peasy, 15 minutes. Spent two hours online reading the forums and nearly bought another tankless online. Slept on it. Woke up remembering one simple post about the same control valve motor being used by other companies. Googled the part number on the control unit (NSAE101). Found one online for $55 (Boston Heating Supply ---Sales@bostonheatingsupply.com) The part is listed as follows: Navien 30011532A Water Adjustment Valve
It comes with a mixing valve that you need to take off and put the Eterrnal part in its place. Put it in and we're back in business.
Note: YOU HAVE TO DISMANTLE THE BAD NSAE101 TO MAKE SURE YOU MATCH THE POSITION OF THE SMALL MAGNET ON THE LARGER GEAR OF THE BAD NSAE101 MOTOR CONTROL UNIT WITH THE NEW NSAE101!
When I first removed the control unit from the mixing valve and took it apart it was full of water and the electronics were probably compromised. The control unit is two halves held together by 4 tabs. I used a small screw driver to pry the tabs back and slipped a piece of 24 gauge wire up into the slot I created when prying apart. With all 4 tabs held out by the wires, the two halves pry apart easily without breaking the tabs.

 

[Work it!]

These pics of the NSAE101 motor control unit to go with the post above. First pic shows how to get the unit apart w/o breaking the tabs. Second pic points to the magnet on the large gear whose position you will need to match in the new NSAE101. Out.

 

[Greg Zaller]

I have a GU195S from 2010. Was having ignition problems then got the E27 and an E03 errors. Ordered the
Navien 30011532A Water Adjustment Valve for $67 with priority mail which arrived in four days. Lubricated the valve with silicone (probably cause of e27) (Prior had water issue from o-ring LEAK above and solved by opening motor and cleaning with wd40 and lubricating with grease. Also protected motor from future leaks) Note: was able to operate by disconnecting motor from valve while remaining electrically connected to computer to remove load and not get error message but water temp fluctuated (good in emergency).

Seem to have solved the E03 error by using torx bit to open gas valve and adjust clockwise 1.5 turns to increase gas flow. Prior would light but switch off due to flame fluctuations. Details: Gas pressure drops from 18 cm water to 15 during operation typically. Gas line is probably 50 ft of 3/4 inch (I know this is long but the unit worked for ten years this way including extended hydronic use)

Question: I thought I could copy valve alignment of Navien unit but it is a different setup so I guessed at the position of the valve when assembling. WHAT IS THE POSITION OF THE ADJUSTING VALVE WHEN REATTACHING TO MOTOR???? I USED 50 DEGREES COUNTER CLOCKWISE FROM FULL CLOCKWISE POSITION. I also wish I could know what all of the dip switches do. My unit has 8 switches on upper right switch areas.