# Furnace flashes a fault code that doesn’t exist in Rheem documentation



## slwtypmark (May 17, 2018)

In the Rheem Installation Instruction/Troubleshooting guide I found on-line, They have '55' & '57' Error codes listed, but no "56". 55 & 57 both deal with the HPS(High Pressure Switch) Do not know if '56' deals with the HPS also or something else. I have a contact at Rheem, I will try to get an answer for you Monday


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## oq1492 (May 31, 2018)

Thank you! Your efforts are truly appreciated. Rheem "Customer Service" told me: (1) that they did not know the answer, (2) that they don't deal with technical issues and (3) the Rheem technical/engineering types who would probably know the answer are only supposed to talk directly with licensed contractors and are not authorized to talk to end-customers. I get it - it's complicated stuff and they don't want amateurs blowing themselves up or CO-poisoning themselves or their families, but come on, just add the code to the published list. I look forward to hearing back from you and relaying any info to the local techs.


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## Chris130 (Feb 3, 2014)

I don't have this furnace, so perhaps I'll be totally off-target here, but does your fault code display as a sequence of long & short flashes (or short & long flashes)?

If so, is it possible that you're perhaps getting the sequence mixed up? 

My furnace does fault codes like that, and every time I've had one come up, I'm pretty sure that I mixed up the sequence the first time I "read" it, so I can well sympathize it's very easy to misinterpret (especially when you get into higher digits like 5, 6, etc)!


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## oq1492 (May 31, 2018)

Thanks for your response, but I'm certain the code sequence represents "56". This unit's method of displaying 2-digit fault codes is to display the first digit for 1 second, immediately followed by a 1-second display of the second digit, followed by a 1/2 second pause. The display cycle then repeats. When multiple faults are present, for example, when the unit enters the 1 hour lockout (code "10") that follows around four code 56 cycles, the code sequence is separated by a dash (-), with the "10" appearing first. I have had way too many opportunities over the past few weeks to confirm that the "5" always precedes the "6".


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## 57TinkerMan (Jun 17, 2018)

It's possible that the analog display does not light up correctly, thereby making a fault code of 58 look like 56. A 58 fault code is "water sensed circuit open". I hope it's as simple as that.


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## 57TinkerMan (Jun 17, 2018)

57TinkerMan said:


> It's possible that the analog display...



Oops, should have said, "LED" display.


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## oq1492 (May 31, 2018)

Thanks for your reply. I'll pass your idea along to the techs, although things seem to be pointing in the direction of the vent system. It recently had to be modified due to combustion gas recirculation issues and it looks like something ain't right.


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## slwtypmark (May 17, 2018)

Still waiting on a call back from Rheem guy oq...yes, '55' & '57' deal with the HPS in the circuit for the Draft Inducer or Vent. Hope to have you an answer asap!(Would be interested to know what kind of 'modification' was needed ???


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## oq1492 (May 31, 2018)

Thanks slwtypmark. When originally installed about a year ago the system was left with combustion gases venting horizontally from the large basement-level equipment room into the crawl space under the house for approx a 4 ft run thru 2" pvc pipe. You could usually smell it out in the driveway but, miraculously we never had a problem with exhaust recirculating into the house itself. However, in the past couple of months the weather has been unusually bad and it appears to have affected the prevailing wind direction or something, causing occassional recirculation into the house and even once setting off the CO detectors. At that point I insisted on them coming back out to redirect the venting. So they connected the existing horizontal 2" pipe to a vertical 3" pipe that travels up about 12 feet and thru the roof. No more recirculation issues, but we only get 1 hour of relatively weak heat at best, then the machine goes thru a series of 4 or 5 short cycles, during which it throws the 56 error code, then locks out for precisely an hour (fault code 10), then repeats the entire cycle, although for shorter and shorter durations.


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## 57TinkerMan (Jun 17, 2018)

By chance is the reducer connecting the 3" to the 2" pipe installed on the horizontal 2" pipe. If so, you would have needed an eccentric reducer or install a concentric reducer on the vertical 3" pipe. You might have a condensate build up beyond the reducer if it is concentric and installed horizontally.


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## oq1492 (May 31, 2018)

There are no eccentric reducers in the set-up, only a concentric attached to the 3" vertical.


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## 57TinkerMan (Jun 17, 2018)

Ok, my last idea didn't pan out. Is this furnace at altitude? Are you using propane or natural gas? I ask because you mentioned the exhaust had a very noticeable odor to it. I know this doesn't solve the 56 error code but may lead to why you are getting an error code in the first place. One more thing when your guys extended the exhaust vent did they extend the intake as well?


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## oq1492 (May 31, 2018)

I'm in the Andes mountains just north of Bogota Colombia at 9,200 ft, using propane. The machine has been adapted for both LP gas and high altitude. Two of my neighbors have identical Rheem furnaces installed and serviced by the same company, and have no complaints. Neither did I until the techs modified the venting and tweaked some gas pressure settings within the past few weeks. The intake vent was not modified, in fact it's "as delivered" with no pipe attached.


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## 57TinkerMan (Jun 17, 2018)

I love Colombia, we spent several months touring around, can't wait to go back. This one is puzzling. So additional questions for you. You furnace is non direct venting. Do you have adequate combustion air available where the furnace is located? Between 9000 and 10000 ft you should have #63 orifices installed in the manifold and gas pressure adjusted to 10" wc. Your exhaust should not be too "smelly". You could drop the gas pressure to 9 or 9.5 inches and see if that helps. And what do think the total length of your vent pipe is and number of elbows etc.? I've serviced quite a few furnaces in Leadville, CO and altitude can do some weird things!


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## slwtypmark (May 17, 2018)

Ok oq, Good news, Bad news(First the Bad) Rheem Guy says there is No #56 Fault Code. He thinks your furnace is probably installed Horizontally & that it's really a '59' He said to have you stand on your head and look at it with your Left eye Closed!  jk (The Good!) It turns out that '59' is for 'High Water'. This would be the area we would be looking at close after you filled us in on the 'Modifications' made! You answered TinkerMan that The 3-2" pvc reducer is installed in the 'Vertical' piping so you wouldn't need an Eccentric reducer but hearing your description of what happens and the shorter and shorter cycles you descibed, it sure sounds to me like the furnace is not draining properly. Maybe the changes to be made at install with drain tubes was not done correctly and you got by(If you want to call being able to smell the products of combustion and setting off CO detectors with a First Year 90+ furnace getting by!) but after they made 'Modifications', it's worse. I hate to say it but I think you need to get a 'New set of Eyes' on the situation. Just because they didn't know what a '56' code was doesn't mean they didn't have a bunch of clues to troubleshoot the symptoms and get to the bottom of it.


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## slwtypmark (May 17, 2018)

Columbia! Now I understand why we are working on your 'Heat'!..You're on the 'wrong side' of the equator, no wonder it looks like a '56'..Close your Right Eye!


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## slwtypmark (May 17, 2018)

Scratch that last! Didn't trust my Geography and looked you up. I guess you are on 'Our Side'...Barely! Didn't realize the Equator is "IN YOUR BACKYARD"!


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## 57TinkerMan (Jun 17, 2018)

I agree with the slow drain possibility. Taken from the link below the text:


“If the modifications aren’t made for our altitude, you get a real sooty flame because the gas/air mixture is running too rich. In condensing furnaces, it can soot up enough that it will block the secondary heat exchanger in the furnace, which will eventually shut off the operation because the condensate won’t drain.”


https://www.achrnews.com/articles/136057-furnaces-must-be-modified-for-high-altitude-applications


Mostly conjecture and not saying that your furnace was not set up correctly but the flue gas odor at the exhaust outlet points to the fuel mixture being a bit rich. Did you notice if the interior of the 2" pipe was discolored? Maybe something your techs can check for you.


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## oq1492 (May 31, 2018)

Thanks everyone - I'm still a little confused since the unit is installed in the upflow configuration shown in the manual and the card is in the corresponding position (not upside down). BUT - I distinctly recall seeing very early in this process when they were doing some sort of testing that the card flashed "6" "E" and I thought that was bizarre since there is no 6E code or anything else with an "E". Of course! it was a "93" Internal Control Fault. And I also recall being surprised at how sooty one of the disconnected elbows was. I'm forwarding the "59" info to the local techs.


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## 57TinkerMan (Jun 17, 2018)

Looks like you found your problem. If your 2" vent pipe is sooty imagine what the internals of the heat exchanger look like. I'm not sure but I think most manufacturers would recommend (at a minimum) replacing the heat exchanger. Based on your comments throughout this thread it sounds like your furnace was not setup properly (orifices/gas pressure) from the start. Modifying your exhaust just helped to speed up the process. One additional thing to check or find out is, did your techs adjust the pressure switch that proves you have sufficient combustion air? Happens all the time here in Colorado. Some pressure switches have an anti-tamper sealant over the adjustment screw. Your switch may have this and it's easy to see if the seal has been broken. If so, get a new switch too. Might be wishful thinking but the furnace should be adjusted with a combustion analyzer especially at your altitude.

Best of luck, Mike


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## oq1492 (May 31, 2018)

Definitely not set up correctly at original install. I now realize that they didn't bother to change out the orifices and precisely tune the incoming gas pressure until 2 or 3 weeks ago, when they came out because of the recirculation issues I was having. When they saw the flame quality and the soot build-up it really caught their attention. They did adjust the gas pressure to 10" wc, but I'm still not sure exactly what size replacement orifices they used. I compared them to the originals when they were working on it and the new ones were much smaller, but I didn't take note of the size. I'll be asking them for confirmation. They also did some clean-up around the heat exchanger and had to clean out the condensate trap at that time.


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## oq1492 (May 31, 2018)

Good article! Given some space limitations, I'll see to what extent they can replace the existing 2" pipe with 3". It's not a long run of 2" (8-10 ft?) but that doesn't include the 2 standard 90 and 2 45 elbows, which I think max's out Rheem's 20 ft guideline for 2" pipe attached to this particular unit.


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## 57TinkerMan (Jun 17, 2018)

Unfortunate circumstances for sure, but it sounds like your techs have been responsive so far. If this happened to me my concerns/questions would be as follows.


1. Furnace over fired, did this warp/distort the heat exchanger.

2. Secondary heat exchanger probably clogged with soot. Can it be cleaned, if so, see item 1. Probably have to pull the exchanger to verify either way. I'm not thinking that corrosion is an issue due to the age of the furnace.

3. What does Rheem recommend, cleaning or replacing the heat exchanger.


4. How they verify (for your peace of mind) proper operation when the repair is completed...combustion analysis, orifice size, gas pressure...

The one problem with sooted up heat exchangers especially at your altitude is you need to get them squeaky clean so you don't have a repeat. Once again I am not really familiar with Rheem products and don't know if that can be achieved with a water/compressed air flush.
If I were in the states I would probably want a new furnace, not that I would get one though.

Looking at the literature again it does state that for your altitude to use a #63 orifice for the burners it goes on to say that #64 orifices are available too. I'd have to look at my orifice/btu chart to see where that would put you btu-wise. I'm sure there are others on this forum with more Rheem knowledge then I have hopefully they will chime in with some suggestions too.

Edit: just saw your last post, have them go 3" no 2" at all.
Edit2: A #64 orifice in place of a #63 orifice would drop the btu's per burner about 500 btu.
Do you live in a really large house, insulated well?



Good luck and let us know how it all turns out.


Mike


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## slwtypmark (May 17, 2018)

I will go along with everything Mike said..except One. This has been a case of "Gross Negligence" from the Install and thankfully you and your family are ok! I would have to switch but If you decide to stay with them, minimum, you must demand they send there most Senior Tech so this thing gets done Right & SAFE!


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## oq1492 (May 31, 2018)

Found an easier solution for the upside-down fault display than standing on my head and looking at it with my left eye: On page 89 of the Rheem manual it says the display orientation is determined by the position of dipswitch SW1 on the dipswitch bank. For an upflow installed unit like mine SW1 should be in the OFF position, as delivered. Someone had set it to ON. I have reset it to OFF and the furnace is now coding an easily recognizable "59".


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## slwtypmark (May 17, 2018)

Good find! I apologize, Rheem guy did mention checking that & i forgot to pass it along!


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## oq1492 (May 31, 2018)

Current status: progress, solutions, but now with a new problem. (1) They replaced all 2" exhaust pipe with 3" pipe, so I now have approx. 64 equivalent feet of properly angled 3" exhaust venting. (2) They replaced the secondary gas regulator because the adjustment mechanism had gotten jammed. (3) Addressed and resolved the error code 59 problem by cleaning out condensate drainage, shortened the travel and adjusted angle of pipes to ensure proper drainage, replaced the condensate trap and the 2 water/moisture sensors. No more "59 - water sensed" error. Now we're getting error code 33, MRLC (Manual Reset Limit Control)(AKA Roll-Out) Open. The furnace will operate between 1 to 3 hours then emit error code 33. Flame goes out and unit just blows cold air until I either turn it off or hit the reset button. It may just be my imagination, but it seems to me that the intensity of the heat slowly diminishes during the time the unit is actually heating. However, at no point is it really giving off an intense heat at the room vents and, at best, we're lucky to get the temperature (as indicated at the thermostat) up from 52*F (beginning ambient temp) to a maximum of 61*F. That's as warm as it gets, even after a 3 hour run time. In a 3000 sq. ft. home with a 115k BTU furnace. The techs are also dealing with the quality of the flame. As it travels thru the initial heat exchanger it quickly goes from a perfect blue to mostly yellow. On the last visit, after eliminating error code 59 and then getting error code 33, the main tech spent his time mainly trying to balance flame quality/error code 33 generation by tweaking gas pressure at the initial and secondary regulators and the furnace's gas valve. It was like watching someone juggling. The initial regulator wound up left at 5 psi, while the secondary regulator has been moved up from 10" wc to 13" wc, and then some tweaking of the gas valve. But the flame continues to look way too yellow and, as I said, the best heat runtime we've gotten is around 3 hours. He has also tested the MRLC switch and says it's OK. And that's where we stand right now. By the way, this unit had no problem achieving a comfortable 68*F at the thermostat when first installed last year, despite the high altitude/LP adjustments having essentially been neglected when it was originally installed. Sure did seem to burn thru a lot of LP gas though, which is why we rarely ran it very long.


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## slwtypmark (May 17, 2018)

Sure glad they came back and made all those corrections but Tinkerman gave the warning to you previously, with all that they did wrong during initial set-up, We kinda expected Heat Exchanger problems and it sounds like that's what you are probably experiencing! Listen, I'm glad they made the other corrections but you need to put your foot down & demand they make this RIGHT!..whatever it takes!..including a New Heat Exchanger! Your other recourse may be that you have to go to Rheem directly. None of this is your fault..no reason you shouldn't be able to keep your house at '68'!


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## 57TinkerMan (Jun 17, 2018)

I agree that your heat exchanger is still plugged. Did the guys actually remove the HX and clean it out? It sounds like from your description that they did everything but that. You will not be successful until the HX is 100% clean. You are also dealing with a major safety issue, do not keep resetting the roll out switch! 



One other thought, are you using propane, butane or a mix? Butane has a higher heat content than propane, remember it's all called propane in Latin America but there is a difference.



http://www.exothink.com/Pages/btu.html


If you are using butane you might want to use the #64 orifices when things get straightened out.


Good Luck, Mike


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## oq1492 (May 31, 2018)

Current (and hopefully final) status: A couple of days after my last update it started throwing error code 59 again, as well as 33. I shut down the furnace, alerted them to the problem and relayed the heat exchanger concerns. Although it turned out to not be necessary, they came out last week ready to take the furnace back to their workshop to overhaul it and temporarily replace it with a similar but smaller "loaner". Before doing so, they took out the heat exchangers. I wasn't present for this event, but they took pictures. Yikes! Nasty. They cleaned everything out with a water hose, etc. Seeing only the pictures, I can't vouch for squeaky clean, but they looked like new in the photos. They also inspected the heat exchangers and found no warping, cracking or other defects. They also cleaned out the condensate trap and drainage (again), including taking apart the induced draft blower for a thorough cleaning. They also installed #62 orifices (#63 not currently available in-country). Turns out that when they originally changed out the as-delivered orifices they did use a smaller size, but still not really in the ballpark for my altitude. They did a little more tweaking of the gas pressure (it's basically back to 10"), turned it on - and the furnace has been working well for a solid week so far. No errors, great heat quality, good looking flames, etc. When I'm up on the roof even the exhaust gasses seem a lot milder smelling. The techs call me every couple of days to make sure it's still running ok, and as long as it continues to function as it should, the plan is for them to come out once a month for the next few months to check the system thoroughly. We have requested that they extend their warranty for another year (no formal reply back on that yet). This has been a great learning experience for all involved and, while I appreciate the techs' tenacity and genuine concern for getting this right, I don't think we would have this solved yet if it wasn't for the great advice and insights provided right here in this forum by 57TinkerMan and slwtypmark. THANK YOU!


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## 57TinkerMan (Jun 17, 2018)

Good news! I'm glad it's working out for you. I'm impressed with the follow through of you techs. Definitely get the #63 orifices installed don't leave anything to chance. One thought I have is, if the "temporary" furnace is new(ish) and has the same efficiency of your original furnace and is heating well why not keep it? The smaller capacity will be more efficient and may provide a more even heat through out your house. You also had mentioned that the techs had adjusted your pressure regulators from their original settings, you might want them to revisit that if they haven't done so.


Mike


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## slwtypmark (May 17, 2018)

I might 'Type SLOOOOOW' but every once in a while I'm able to chip in for the greater good of the DIYer!  Glad this thing looks like it is getting resolved! Glad they are doing whatever necessary to make it right(And SAFE!)..and the continued monitoring sounds real good..you can't take any chances with Gas appliances! Glad you can sleep Safer & Warmer now!  Mark


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## mikefrommi (Mar 5, 2011)

Hi, realize this thread is a little old. But I came across a code 65 today. It was caused when I shut the LP Tank off to do some work. I assume because of loss of LP to the pilot. I shut the sys off per the lighting instructions - turn it to low - turned the sys back on (the pilot & main burn came back on) - and set the temp.


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