# Repair or Replace?



## Greg Di (Mar 12, 2005)

I would like to get some impartial reccomendations from those who know here online.

I have a Ruud UGDG-10EAUER gas-fired furnace in my house. I have had to replace the IFC once before about 3 years ago. Now, the furnace is short-cycling in that the HSI is glowing, the blower runs, and the burner lights, but goes out after less than 5 seconds. The furnace is constantly running on and off and the house is getting colder and colder.

I got a price to replace the IFC and HSI of about $600. I also asked how much a new furnace would be and it's $3,200.00 for a Carrier 58-STA090-116.

What would you do if it was your house? I'm not keen on dropping over $3k and honestly, I have no clue if this is a good price or even a good piece of equipment.

Thanks for your help.


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## trollmaster (Jan 2, 2007)

It sounds like what you are describing is a bad flame sensor.usualy about a 20 dollar part.If you do need a board and can change it yourself I would say you can get that for less than half that price. Probaly around 250.


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## hf05 (Mar 14, 2006)

I'd agree with the dirty flame rod.How old is the furnace?There does come a time when its foolish to put good into bad.Usually a piece of sandcloth on the rod and your good to go without actually microamping the sensor


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## #CARRIERMAN (Jan 4, 2007)

Hi Greg Di

I just read over this, I agree that for some reason your rectification circuit is not reading a good ground. If cleaning the flame sensor does not do the trick, take a jumper wire and attach it to the burner that the flame sensor is in line with. Attach the other end to a good ground at the control board and see if this stops the problem. The particular furnace you have should have a stamped endshot burner, they have problems with rusting and will not read a good ground. If so the part number for new burners are 752254002. They generally cost somewhere around $8.00 - $12.00 per burner. As far as the Carrier goes, I would personally go to the 90 plus unit, gas prices are not going down. And anything Carrier builds is of the finest quality, but I am a little byassed.

Good luck
Rusty


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## Greg Di (Mar 12, 2005)

Thanks guys!

I sanded off the flame sensor and for now, it looks that that little trick worked. 

The far right burner is stamped galvanized metal and it does have some rust on it (good call). I took it out to check and it's not rusted too badly.

The flame sensor is not attached to the the rusty burner, so I'm confused how that one being rusty affects the electrical system with the ground. Please educate me. As much as I am not an HVAC tech, getting into this furnace somehow interests me now that I see how it's put together.

There's also some kind of sensor above the burners, that's a little round metal circle that pops like a snapple bottle cap. I assume that is some sort of heat sensor? 

Since most of this stuff is pretty plug and play and I can order the parts online, should I replace the HSF, all the burners, and get a new Flame Sensor? I noticed there is a tiny scorch/burn/heat mark on the actual circuit board of the ICF on two resistors. It's not a burn-burn as much as a mark that tells me those two little buggers are getting hot. Is that normal?

Thanks for all your help. You have no idea how much I appreciate it. Plus, my wife stopped nagging me to get the thing working!


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## mdshunk (Mar 13, 2005)

Here's how a rusty burner assembly comes into play... 

That board is basically completing a circuit or a "circle" from the ground connection on the board, through the chassis of the furnace, through the burners, through the flame (the flame is conductive), through the flame rod, and through that rod wire back to the board. If the connection between the burner to the chassis is rusty and the flame to the burner area is rusty, that causes troubles. I've already run extra ground jumper wires to every place certain troubled burners mount to the frame of the furnace to solve a little of this.


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## #CARRIERMAN (Jan 4, 2007)

Hi Greg Di

Md did a good job explaining the flame circuit. The snap disk you are seeing is called a rollout limit. This is in case the flames come out of the burners backwards, and yes it can happen. This will generally happen if the unit gets sooted up or has a bad heat exchanger cell. The dark spot on the board will be around a pair of resistors. This is typically nothing to worry about. The board will typically have no problems. It will let you know when it does though.

Good luck
Rusty


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## Greg Di (Mar 12, 2005)

Thanks guys.

If I do end up needing to jump the ground, should I just take a wire, put it under one of the burner screws and then tie it into the ground from the power feed? Does it matter which burner I tie into or should I tie into all of them?

So far, the furnace is running well since I sanded the Flame Sensor. I can't believe the tech that came out didn't at least do that to get the unit working. Instead, he wanted to replace the IFC that turns out isn't even bad. Makes me wonder if they were scamming me or if he just wanted to do it "right" and replace everything so there would be no call backs.

What I can't believe is that the actual Carrier furnace he wanted to put in goes for less than $900 wholesale. That tells me that he was charging $2300 in labor for a simple install? Man, I'm in the wrong business! I don't mind paying for good work, but for a pretty plug and play operation, I can't see how that price is justified and I have a pretty good grasp of operating costs, overhead, etc...


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## FemaleAstarCO (Jan 25, 2007)

The guys did a great job walking you through all that. The flame sensor cleaning will probably do the trick its a fairly common issue now a days. I have probably 40 no heat calls a week that are just dirty flame sensors. I have to disagree however with Carrier. I have watched the production of Carrier over the years and the quality has decreased as the ads have increased. The biggest problem that I have found with Carrier is they become loud after a few years. The other problems are costs of repairing. Carrier parts are expensive. Far more for a Carrier board than a universal board. However Carrier is hard to match with Universal parts. Sorry Carrierman. This is just in Colorado I do not know about Jersey I have a brother in HVAC there I'll ask about the prices next time I talk to him. I know your prices are very high there as our average furnace installed here is $1900. Good luck.


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## #CARRIERMAN (Jan 4, 2007)

Hi FemaleAstarCo

Not a problem, I know everyone has different opinions, thats why there are so many maufacturers.

Rusty


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## mjm0073 (Jan 27, 2007)

*carrier furnace problem*

i have a customer that has a carrier two stage , variable speed furnace that is 4 years old. the klixon switch on the sealed combustion chamber trips at times. i noticed the top of the furnace gets real hot when it is in low speed only. i have checked gas pressure , burner alighnment , condensate drains , exhaust pipe and combustion air pipe. not sure where to turn from here , looking for ideas. thank you .


mike


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## #CARRIERMAN (Jan 4, 2007)

Hi mjm0073

I left you a response on your other post.

Rusty


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## NCSteve (Feb 3, 2007)

If Its Not Broke Dont Fix It, Get On A Maintenance Plan With A Reputable Company.


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