# Ruud Furnace Won't Fire



## SKIP4661 (Dec 3, 2008)

If the valve is clicking and not opening the main valve it is probably the gas valve.


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## HvacWiz (Nov 24, 2006)

*Check for 24v at valve when you hear it click, if you have 24v, you will need to replace the valve.*


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## jasonckcmo (Dec 22, 2008)

How do I check for 24V? Do I turn my multimeter to AC Volt, ground the black and put the red on one of the two terminals going to gas valve or what? I think I need to go get a new meter too. Don't think this one is working anymore.


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## yuri (Nov 29, 2008)

Check for 24 volts from R to C on the circuit board to verify that your meter works. If not buy a new one. Then check for 24 volts across the 2 wires on the gas valve while the igniter is glowing.


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## jasonckcmo (Dec 22, 2008)

ok, I'll do that as soon as it quits again. I just went down and pulled some connectors off and put them back on and the furnace fired this time. Gonna get this house warmed up first. (62 F.) Thanks for all the help, will keep posting.


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## jasonckcmo (Dec 22, 2008)

Ok, had to go buy a new meter. So now I checked to Volts at the valve and it shows 00.1 while the furnace is going through its startup cycle. When the valve clicks, it jumps to 5.x and 7.x once. It then did fire up, and read 26.x but that was after several trys. Does anyone have any ideas?


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## har199 (Jan 15, 2009)

*ruud furnace wont ignite*

sounds like your gas valve is on its last leg. a replacement valve is probably needed soon especially if its the original valve.


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## JohnH1 (Jan 9, 2009)

jasonckcmo said:


> Ok, had to go buy a new meter. So now I checked to Volts at the valve and it shows 00.1 while the furnace is going through its startup cycle. When the valve clicks, it jumps to 5.x and 7.x once. It then did fire up, and read 26.x but that was after several trys. Does anyone have any ideas?


Normally at 5 or 7 vlt the valve wont click. Since it clicks it sounds like the valve is trying to open. But if you are trully only getting 5 to 7 volts you may have a bad board.


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## jasonckcmo (Dec 22, 2008)

I think its the board. I can jump a wire from 24v on the board up to the gas valve when it is ready to fire up and it does. If i hold that wire there for awhile, then take it off, it will usually run on its own, but not everytime. It will usually quit in the middle of the night. Then sometimes when I remove the jumper, the gas valve just closes.


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## frankie3s (Jan 6, 2009)

Check all the wire connections on the board and make sure that your grounds are OK. In some of the other posts, people have mentioned that the some PC boards have had bad solder joints and/or lose molex connectors.


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## hallwayhouse (Oct 31, 2009)

*Did you replace the circuit board or the valve?*

I am about to replace the valve on my Ruud furnace. It's the same age as yours and having the same symptoms. I have replaced these kinds of parts on other units over the years and believe it's time to replace the valve. I am wondering if you ended up replacing the board too. thanks!


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## frankie3s (Jan 6, 2009)

I had a Lennox furnace that had the same issue and in the end replaced the gas regulator and the problem has since been resolved (did this last winter).

What I think caused the regulator to fail in the first place (beside normal wear and tear issues) was that the Honeywell thermostat that I was using was too sensitive. The furnace would stop and then come back on 5 to 6 minutes after. I replaced the thermostat with a Lux one that I bought at Costco for $50 CDN and it is working exactly as it should. Not coming on more that 3 or 4 times an hour (I remember reading somewhere that the furnace should not be coming on more than 6 times and hour. In my previous case it was like 10!).


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## hallwayhouse (Oct 31, 2009)

frankie... thanks for the response... my situation is exactly like the orginal post here. The thermostat calls for heat, the draft inducer kicks in, the glow plug lights for about a minute, then you hear a click from the valve, (usually this is when the valve opens to let the gas through) instead, the glow plug turns off and the furnace blower continues to run. What do you mean by "gas regulator" do you mean the valve? I am happy to also replace the thermostat. It's 15 years old too and a cheap one. 

A couple years ago I had a similar problem with another Ruud furnace, and replaced the glow plug, valve, and the circuit board. Nothing worked and I replaced the furnace.


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## frankie3s (Jan 6, 2009)

hallwayhouse said:


> frankie... thanks for the response... my situation is exactly like the orginal post here. The thermostat calls for heat, the draft inducer kicks in, the glow plug lights for about a minute, then you hear a click from the valve, (usually this is when the valve opens to let the gas through) instead, the glow plug turns off and the furnace blower continues to run. What do you mean by "gas regulator" do you mean the valve? I am happy to also replace the thermostat. It's 15 years old too and a cheap one.
> 
> A couple years ago I had a similar problem with another Ruud furnace, and replaced the glow plug, valve, and the circuit board. Nothing worked and I replaced the furnace.


Yup, I mean the valve. The one the op had quoted "Honeywell gas valve VR8205H" is known to have a lot of issues and Honeywell had discontinued some of them and had replaced it with something newer. If you have cleaned the flame sensor and the above problem is still happening then it might be time to replace the valve.

Click here to find out if your gas valve has been discontinued and what the replacement would be,
http://customer.honeywell.com/Honeywell/CatalogNavigator.aspx?Definition=ObsSearch&Catalog=&ChannelID={03E741AF-5630-4558-8935-E56D3759DC16}&SearchFrame=ALL&ReturnUrl=http://customer.honeywell.com/honeywell/UI/Templates/CMSTemplates/ProductXRef.aspx?NRMODE=Published%26NRNODEGUID={076DF614-2EDB-481E-8A9A-4DE159079029}%26NRORIGINALURL=/Business/Cultures/en-US/Products/Cross+Reference/%26NRCACHEHINT=Guest



I hope this helps!


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## frankie3s (Jan 6, 2009)

hallwayhouse said:


> frankie... thanks for the response... my situation is exactly like the orginal post here. The thermostat calls for heat, the draft inducer kicks in, the glow plug lights for about a minute, then you hear a click from the valve, (usually this is when the valve opens to let the gas through) instead, the glow plug turns off and the furnace blower continues to run. What do you mean by "gas regulator" do you mean the valve? I am happy to also replace the thermostat. It's 15 years old too and a cheap one.
> 
> A couple years ago I had a similar problem with another Ruud furnace, and replaced the glow plug, valve, and the circuit board. Nothing worked and I replaced the furnace.


Yup, I mean the valve. The one the op had quoted "Honeywell gas valve VR8205H" is known to have a lot of issues and Honeywell had discontinued some of them and had replaced it with something newer. If you have cleaned the flame sensor and the above problem is still happening then it might be time to replace the valve.

Click here to find out if your gas valve has been discontinued and what the replacement would be,
http://customer.honeywell.com/Honeywell/CatalogNavigator.aspx?Definition=ObsSearch&Catalog=&ChannelID={03E741AF-5630-4558-8935-E56D3759DC16}&SearchFrame=ALL&ReturnUrl=http://customer.honeywell.com/honeywell/UI/Templates/CMSTemplates/ProductXRef.aspx?NRMODE=Published%26NRNODEGUID={076DF614-2EDB-481E-8A9A-4DE159079029}%26NRORIGINALURL=/Business/Cultures/en-US/Products/Cross+Reference/%26NRCACHEHINT=Guest

If you do switch out the valve with a newer one (which is probably the issue providing that you did first clean the flame sensor), Personally I would also look at changing the thermostat seeing that it is 15 years old. I'm sure over time they do wear a bit and a new more modern one maybe more accurate. I had a top of the line Honeywell one that caused my furnace to cycle too much. Now that I had replaced it and the valve the furnace is working exactly as it should.

Here is the thermostat that I bought at Costco for $50 CDN,
http://www.luxproducts.com/thermostats/tx9000ts.htm

And it's touch screen too!

Disclaimer:
I must stress for safety purposes that only qualified, trained people should be working on furnaces or the repairing or replacement of. 

I hope this helps!


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## hallwayhouse (Oct 31, 2009)

yes, this is very helpful. I don't even have to look this part up. I have 3 of these furnaces in an apartment building. I have replaced these valves in the past. I don't know for sure if I have replaced this one, but if I did, it could have been replaced with the same faulty valve. The trick is making sure I buy the updated version of this valve. So I will look at the honeywell site to figure this out. thanks again! the disclaimer is also noted.


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## hallwayhouse (Oct 31, 2009)

*replaced the valve.... still not working*

So I bought a new Honeywell valve and the installation was comleted a couple weeks ago. I was so deflated because it didn't fix the problem. I have been so busy I haven't been able to continue working on it. I will be working on it again this Saturday and plan to test the 24 v coming to the valve and suspect I will discover the valve isnt getting the 24 volts to open the chamber. Everything else with this system is working. I reconnected both wires running from the board to the valve and no change. Does it make sense to plan on replacing the board?


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## frankie3s (Jan 6, 2009)

hallwayhouse said:


> So I bought a new Honeywell valve and the installation was comleted a couple weeks ago. I was so deflated because it didn't fix the problem. I have been so busy I haven't been able to continue working on it. I will be working on it again this Saturday and plan to test the 24 v coming to the valve and suspect I will discover the valve isnt getting the 24 volts to open the chamber. Everything else with this system is working. I reconnected both wires running from the board to the valve and no change. Does it make sense to plan on replacing the board?


Definitely check and ensure that you are getting 24v to the valve. Before replacing the board, make sure that the voltages coming out of any transformers (my furnace had 2 close to the board) are correct also.

Another thing that you'll want to do is to make sure that all the wires are plugged in firmly everywhere and don't hesitate to wiggle them a little as you're checking on them. I've read in other forums about bad solder joints on the board also. If you do remove the board, don't forget to label the wires first and then look on the other side for bad solder joints.


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## hallwayhouse (Oct 31, 2009)

*I am getting closer....*

I was able to get the furnace to light. It is not lighting consistently. Here's what I did to get to this point:

I used a can of air to clean the dirty circuit board. As soon as I did this the furnace worked right away. But didn't light on a repeated cycle. 

Now what happens is the furnace begins it's cycle, the hot surface lighter begins to glow, the valve clicks, and you hear gas starting to flow, then the fan blower kicks on (before the fan blower wouldn't even run) and the burners don't light. It will do this cycle several times, and then shut down the furnace. Then you can cut the power to the furnace and begin the cycles over again and the burners may light. 

Also, I checked for bad solder joints and found nothing wrong. The back of the board was also very dirty. So I cleaned it up and am getting the same results. 

At this point, it is either the transformer (I only have one connected to the board) or the circuit board. Since I am able to get a read of 24 V from the valve after it clicks, I don't think it is the transformer. 

Is it possible for a circuit board to work intermittently? If so, I will replace the board and should be done with this. 

Thanks for any further comments and suggestions.


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## frankie3s (Jan 6, 2009)

hallwayhouse said:


> Now what happens is the furnace begins it's cycle, the hot surface lighter begins to glow, the valve clicks, and you hear gas starting to flow, then the fan blower kicks on (before the fan blower wouldn't even run) and the burners don't light. It will do this cycle several times, and then shut down the furnace. Then you can cut the power to the furnace and begin the cycles over again and the burners may light. .


What you had mentioned here sounds like the board is functioning normally. Because there are no moving parts on the board it is very rare for it to fail intermittently much like a mechanical device would. The statement that you had mentioned above makes me still think it could be a gas valve issue but you had mentioned that you did replace it with a new one so I'm very reluctant to reconsider it. 

Maybe the flow of gas to the gas valve has gone down (though rare)? I was thinking when the burners cycle several times and then finally ignites it could be only after a build up of gas is in the chamber? On the Honeywell gas valve you can adjust the flow. Make sure to note the position of where the screw is before you adjust it (the manual that came with the gas valve will tell you how). 

The only other thing left would be to look at the flame sensor again and to make sure that it is clean so that it will able to detect the presence of a flame. You can use steel wool or sandpaper to clean it with. You're not going to like this but I think we're not done with the gas valve yet. If the place that you had bought it from is anything like we have here, it's not uncommon that used/bad valves are exchanged with good ones and then returned for someone else to have fun with. 

I'm so anal about this that I look parts over like a hawk and if I see a mark on the electrical contacts or adjustment screws, I reject it.


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## Marty S. (Oct 31, 2009)

Clean the burners,gas orifices and crossovers. After that check incoming and manifold gas pressure.


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## hallwayhouse (Oct 31, 2009)

Another point of clarification.... this furnace has a Hot Surface Ignitor, there isn't a flame sensor. I have another Ruud/Rheem furnace with a standing pilot, but with this furnace there is only an electronic HSI

It seems to me that there should be an answer to a couple simple questions. 

Will a circuit board function intermittently? (this board was very dirty and could not get the furnace to light before I cleaned it) 

Will a transformer function intermittently? (all or nothing?) 

What would change the gas flow or pressure? 

The Honeywell gas valve looked brand new to me with no signs of a previous installation. 

If there was a gas flow problem, why does it ever light and run through a cycle? It would seem as though there isn't a gas flow problem. 

Also, I cleaned the area around the burners. I didn't take them apart and clean, but I did clean the area. 

thanks for the responses!!!


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## frankie3s (Jan 6, 2009)

hallwayhouse said:


> Another point of clarification.... this furnace has a Hot Surface Ignitor, there isn't a flame sensor. I have another Ruud/Rheem furnace with a standing pilot, but with this furnace there is only an electronic HSI
> 
> It seems to me that there should be an answer to a couple simple questions.
> 
> ...



Reading from http://homerepair.about.com/od/heatingcoolingrepair/ss/furn_electr_ign_4.htm it offers some good advice about HSI. Specially some things to look out for and it does mention that there is a flame sensor,

*"Hot Surface Ignition *
The hot surface igniter is the most commonly used electronic ignition system used today. The reason is they are reliable, inexpensive and the electronic controls they require are also less expensive. *All they require is a flame sensor to detect the igniter glow and open the main burner valve.*"

Another point....

"Under normal conditions the igniter should last for 3-5 years. However, it will eventually crack and need to be replaced, quicker if the oils from your skin get on the element by improper handling."

Go through this information and see if any of it applies. Also, there has to be something to detect the presence of a flame for sure.


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## hallwayhouse (Oct 31, 2009)

I get the flame sensor now.... all this time I assumed flame sensor was for a pilot.... there's another thread at this site that shows some pictures. this Ruud system looks exactly like mine and helps me understand the flame sensor. 

http://www.diychatroom.com/f17/ruud-furnace-issue-upgrade-board-flame-sensor-55399/

I have not cleaned the flame sensor as you suggested a few weeks ago. So now I think I have more I can do to make some progress here. The fact that the furnace works intermittently lines up with the flame sensor (a somewhat mechanical device) theory. 

I will do my best to clean the flame sensor, burners, etc.. and hope to finish this project. 

The weather is finally starting to get cold around here so I need to get this right soon. thanks again!


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## Marty S. (Oct 31, 2009)

Dirt,rust and spider webs cause gas blockage or partial blockage. They can also plug regulator vents causing drops and spikes in pressure. All of that can and does cause an ignition failure. New gas valves need to be adjusted properly. Once again, clean the burners-clean the gas orifices- check the gas pressures with a manometer.


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## hallwayhouse (Oct 31, 2009)

*Ruud furnace is running again!*

Thank you all who chimed in about my furnace problem. I am very satisfied and cherish the knowledge I gained through troubleshooting this furnace. The flame sensor had a little bit of residue on it. Probably enough to disable it. Also, I know the orifices were dirty. The 2 burners are flowing stronger than before. 

Part of my problem with this furnace was not having great access to the system. It sits in a hallway closet and I only have an approach from the left side. I never even noticed the flame sensor until today. 

About 4 years ago I had a similar problem with the same kind of furnace and ended up replacing it. I really appreciate this DIY website and will recommend it to everyone. 

:thumbup:


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