# Ruud Furnace issue



## grubslinger (Oct 24, 2006)

The weather is just now getting cool enough to fire up the furnace, so of course I'm encountering problems like so many others I see. For the first week or so, it was working properly, but in the past couple days its been acting up. It seems to be shutting down for some reason and will not fire up until I cycle it a few times from off back to heat. 

When I cycle it to off, then back to heat I can hear the furnace ignite and if I walk outside it is blowing warm air out the exhaust. So it appears to be lighting properly (or as best as I can tell). After about 1 minutes time, it will shut down. Sometimes the blower will kick on and will blow warm air as usual. however, more times than not the blower will not kick on until I cycle the unit a few times. 

Once it does actually begin working, sometimes it will work properly for a few hours, sometimes it will only kick in about 2 or 3 times before it eventually shuts down again. 

At first, I thought it may have been something with the thermostat, I replaced that but its still doing the same thing. I dont really know a whole lot about HVAC, however I am fairly mechanically inclined and if there are some basic troubleshooting things I can do without calling in a professional that would be great. Any advice?

the furnace as best as I can tell is a ruud 3 ton central air/heat unit and was installed when the house was built in 1997. I cant seem to find any more documentation than that.


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## #CARRIERMAN (Oct 18, 2006)

Hi grubslinger

Try turning the fan switch on you thermostat to on, the blower should come on almost instantly. If this happens chances are your blower motor is ok. If it starts kind of slowly it probably needs a run capacitor. The motor usually makes a destinct growling sound when the run capacitor is bad. If the motor makes this noise, take the run capacitor off and have it tested. It has to be within 10% of it rated microfarads. Anyone with a Fluke 12 or higher can test it for you.

Good luck, let me know if it doesn't work.
Rusty


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## grubslinger (Oct 24, 2006)

the fan does work if in the on position. It does not blow warm air, but it does work.

--edit--
I guess I should say it does not blow warm air after the unit has shut down. Occasionally leaving the fan to on will result in it blowing warm air, but only after I reset it.


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## #CARRIERMAN (Oct 18, 2006)

Hi grubslinger

That helps me understand a little more of whats going on. This unit appears to be electronic ignition. What probably needs to be done is the flame sensor cleaned. Use a wire brush DO NOT USE SANDPAPER! Make sure to shut the power of to unit before performing this, the flame sensor rod can have voltage on it. Give this a try, let me know if I can help any further.

Rusty


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## grubslinger (Oct 24, 2006)

thanks Rusty,

I've been doing a bunch of reading and I've thought the same thing. I'll have to give this a try once I get home tonight.

Just so I'm understanding this correct, the flame sensor basically is there to ensure that the unit ignited properly to prevent unburnt gas from leaking out and causing a quite explosive situation correct?

So by the flame sensor being dirty or faulty in some way, the unit is shutting down and not allowing it to re-ignite after the initial reset for a safety precausion?


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## #CARRIERMAN (Oct 18, 2006)

Hi grubslinger

That about the best way to put it. It looks like you have a pretty good grasp on the issue. Just one last note, when you pull flame sensor out be careful not to damage porcelin. If you do you will need to replace flame sensor. Don't let this detour you, you will be fine.

Good luck.
Rusty


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## grubslinger (Oct 24, 2006)

One last question. How difficult is it to access the flame sensor, and do you have any general guidlines on what I'd have to do to get to it? Is it usually pretty easy to access or do I have to have a degree in physics to get to it?

As I said, I'm a novice to hvac since I'm a first time homeowner and this is the first problem I've had with it, but I'm quite eager to learn.


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## #CARRIERMAN (Oct 18, 2006)

Hi grubslinger

Usually speaking Rheem/Ruud are very easy to work on. Even us toiletcscrubbers can do it. Just kidding. All you have to do is look for the stainless steel rod with a single white or orange wire coming off of it. You will probably need a 1/4" nut driver to pull it out. Just take your time, if you have any further questions this toiletscrubbing physics professor will help.

Good luck.
Rusty


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## grubslinger (Oct 24, 2006)

Thanks for the help so far. I just got home, pulled the flame sensor, and although it didnt appear dirty I did give it a little cleaning.

However, that was not my problem afterall. After re-installing and testing it still did not function properly. So I had the wife operate the thermostat while I watched what was happening.

Its got 4 burners, the igniter is on the left one, flame sensor on the right one. When the unit kicks on, only the left burner is lighting. I'm assuming there is some method for it to cross-ignite the other burners, but that is just not happening. Thus, the flame sensor isnt getting the proper reading and shutting the system down.

Is there anything further I can do or is it now in the hands of a professional?


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## #CARRIERMAN (Oct 18, 2006)

Hi grubslinger

Now you can fix your furnace, all you need to due is remove the burners. Use your wire brush and clean them really good. If the burners are in really bad shape ( rusted badly ). Go to your nearest Rheem/ Ruud dealer and get some new ones. They generally range between $12.00 to $20.00 per burner. See i told you it wasn't that bad. If you lived in Independence Ks, I keep these burners in stock.

Good luck.
Rusty


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## grubslinger (Oct 24, 2006)

Thanks yet again. I sure hope that is the problem.

Just so I understand the mechanics at work, how does it cross ignite the other burners? Of course, when I get the burners out and begin looking at them, I may be able to answer my own question.


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## grubslinger (Oct 24, 2006)

Thanks Rusty.

I pulled the burners, ran to Lowes to get a smaller wire brush since mine wasnt well suited to the job, cleaned, and reinstalled. They were indeed a bit on the rusty side. After a thourogh cleaning and reinstalling the system is firing all 4 burners right off the bat.

The problem seems to be solved and all it cost me was a few hours and 2 bucks for a wire brush. No more waking up with frost on my nose!

Thanks much for your advice,
Brad


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## #CARRIERMAN (Oct 18, 2006)

Hi grubslinger

Thats what I joined for. Glad your furnace is running. Have a safe and happy winter.

Rusty


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## nursemaid (Nov 4, 2006)

*help with my ruud*

Hello
OUr furnace was working good now all of a sudden it's decided to stop we replaced the thermostat you can hear the blower come on but all it does is blow our cold air I am guessing that the burners are not lighting.It doesn't have a pilot light it has some kind of ignition system.Any ideas would be welcomed seeing how we can't reach our landlord and its the weekend.
Thanks Lorrie


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## nautilus_3 (Mar 8, 2007)

*I too am having an issue with my RUUD*


Hello, im having issues with my RUUD Furnace. Its an LP, with a hot surface igniter..

When I go to the thermostat, you can turn the fan on and works fine. Set it to Auto, then noting happens. I go the furnace and open the service panel and see and hear nothing. I bought a multimeter and checked for continuity and voltage and all seems to be ok. I checked the Voltage on the HSI and it showed 12 or 24 volts (cant remember exactly).. so I assume it was trying to work, unless there is always a voltage on that.. Looking at the control module the HSI is hooked up to, is showing that everything plugged into that section is 120Volts. So maybe it goes from 12 or 24 volts to 120 when the system activates. But what could cause it not to activate. I'm kind of stuck in the fact that im not sure what to check next. I keep hearing about Flame Sensors but I cant seem to locate mine.. Its a RUUD and im not sure of the model. Its about 14 years old.

Thanks,
Chris


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## rakes9720 (Dec 13, 2006)

Turn the thermostat up real high and go see exactly what happens. First the little inducer motor should turn on. Tell us what happened.


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## nautilus_3 (Mar 8, 2007)

sorry it took a long time to get back to this. Basically, I ended up letting the problem sit till that next winter hit and was forced to deal with it and call in the Pro's.

Called in an HVAC company and they traced it to a faulty controller unit. A replacement module was not available (probably due to its age) and a universal type unit was installed (thankfully such a thing exists as I couldn't afford buying a whole new system). Once that was replaced, it fired up nicely. Total job cost $750.. 

Still runs like a champ today. Although now the system is almost 20 years old and now im thinking of getting a more efficient unit... Also to avoid any new problems that tend to occur with age and use.

Thanks for the help!


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