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Replacing or Repairing an Older Furnace

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1victorianfarmhouse

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Last spring I was having issue with the main furnace (Luxaire) in my house not working reliably. It's older, I think it dates to 1996. Mainly, it wasn't coming on regularly. it might be a gas valve or pressure switch and that problem may be the main issue, or there may be others. From peering into it when it was working, I think the Heat Exchanger was showing signs of rusting out in some areas, and some other parts might also be suspect. I have no problem with disassembling it, and the quality of the original installation is better that what I've seen in friend's newer basements. My question is whether I can get the proper replacement parts without having to buy an entire new furnace? Thanks, Vince
 

Sparky617

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Gas or oil? A 24 year old furnace with a rusting heat exchanger is getting pretty long in the tooth. A new one is going to be much more efficient. Our gas furnaces and ACs are 21 years old and I'm getting ready to replace both systems. Over the past year I've had to add more refrigerant, replace a starter relay and a blower motor. Through good maintenance I've been able to keep mine going much longer than my neighbors, but there comes a time when you just need to stop throwing money at it. I was fortunate that when the blower motor seized up I was able to get a new one installed into the housing at a local motor shop for $125. I didn't mind putting that into the unit to push the replacement out another six months or so. Just having AC until I could get the unit replaced would have been worth $125.

No one here can assess whether it is time to throw in the towel on your unit. I'd get a good independent HVAC tech to come out and service the unit before heating season. Parts can be hard to come by for someone who isn't licensed. My local Carrier supplier won't sell me parts. I've bought some online, but shipping can be a killer on large or heavy parts. I have a great HVAC contractor who believes in keeping it going as long as possible. Places like ARS specialize in selling new units. I have neighbors getting ready to replace their replacements. ARS will recommend replacing anything over 7 years old. I've gotten 3x that out of my units while maybe spending $2500-3000 in annual inspections and repairs.
 

1victorianfarmhouse

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Sparky, thanks for the great reply! It's a gas furnace. I've heard that some parts may be tough to get, but not sure just which they might be yet. I am always tempted to try and repair things unless buying a new one makes sense both financially and operationally. You make a very good point about the newer ones being significantly more efficient. I'll admit that I'm reluctant to call someone in to look at it as I don't want to be wasting their time if they are hoping to sell me on a new one plus installation that I would rather buy and install myself to save a good deal of money.
 

Sparky617

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Sparky, thanks for the great reply! It's a gas furnace. I've heard that some parts may be tough to get, but not sure just which they might be yet. I am always tempted to try and repair things unless buying a new one makes sense both financially and operationally. You make a very good point about the newer ones being significantly more efficient. I'll admit that I'm reluctant to call someone in to look at it as I don't want to be wasting their time if they are hoping to sell me on a new one plus installation that I would rather buy and install myself to save a good deal of money.

Try to find an independent HVAC guy. Personally I'd never use ARS. If you know any good real estate agents they usually have HVAC guys they know and trust to do HVAC inspections when they are working with buyers of existing homes.
 

1victorianfarmhouse

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Thanks for the replies! I'm trying to break in a new computer, and having fun figuring out all my passwords and usernames, LOL.

I've dealt with HVAC guys in the past, and they all want to sell a new furnace for big bucks. Trying to find a guy who can actually troubleshoot anything is difficult. When I bought the house 10 years ago, the furnace didn't go on when it should have, and I called a local place. It took him about 10 minutes to figure out he needed to sell me a new furnace for 4k. I thought it was odd that the furnace worked fine when the inspector tested it a couple weeks before. A friend of mine who's a mechanical engineer stopped by a couple days later, looked at the furnace, unplugged a few things and plugged them back together, and told me the motor wasn't going on and I should get a replacement motor. I did and that solved the problem for $180. Having worked on cars as a hobby for 30+ years, I have little appreciation for people who can't or won't diagnose something and instead quote a big price hoping to find a sucker.

The past few weeks have been interesting with the furnace. I've begun to think the problem may lie with the thermostat. It is an older (10 years or more). round Honeywell. The weather was fairly chilly, in the 20s and below for a week, and the furnace would start up only sometimes. I would have the thermostat set at 70. and the temp in the house would get down to about 55 without the furnace starting. I carefully blew and swabbed the dust off the glass tube and rest of the insides. The past week the temps outside were in the upper 20s and lower thirties, and the furnace worked flawlessly. Inside temps were warmer, too.

Today the furnace didn't greet me with warm air in the morning, and the outside temp was 21, inside temp was upper 50s. Furnace wasn't turning on, but the inducer was running and had been running. I shut it off, and turned it back on. Within a minute the pilot came back on and lit the furnace. It'll be interesting to see if it keeps the house warm today or it it chooses to be temperamental.

Does this sound like a simple thermostat? Comments always welcome!

Thanks as always!

Vince
 

BuzzLOL

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The inducer produces a vacuum that is sensed by a vacuum switch that then tells the furnace it's OK to proceed to the next step... that switch may be going bad... or it could be the igniter... or flame semsor...
In my furnace the thermostat closes a 24 volt circuit that causes a solenoid to close and energize 120 volts for the rest of the steps... the 20 year old solenoid was having trouble pulling up, needed to tap it first time furnace turned on in fall, got me 5 more years... then that didn't work, so I remounted it upside down to let gravity help it against the spring... bought me 10 more years, but it's prolly time for a new solenoid now... or maybe it can be disassembled and cleaned... haven't got into it yet...
 

tmiskimen

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May be the flame sensor. Could just need cleaning. Our dau. had this problem. Furnace would not come on in morning then by the time she got home from work it was fine. Turns out the flame sensor needed cleaning and her nice repair guy even showed her how to do it. In the morning when everyone was turning up their T'stat the gas pressure in her allotment would drop slightly and the flame sensor would shut the furnace down then after 8 hours the furnace would try again. By this time gas pressure was back up and all would be fine. All furnace electronic logic is a bit different so don't know if this applies to your situation.
 

NeilG

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Warning Signs: When you may need to replace your furnace

16-20 years: The average life expectancy of a furnace
A few weeks ago, I turned off the gas, probably for the last time, on a 67 year old floor furnace. I was smelling gas. We live in SoCAL, so I'm using electric spacer heaters for the few hours in the morning when we need it. No problem with freezing pipes, as 40F is about as cold as it ever gets, and only at night. When the plague is over, I'll have someone install something new.
A few years ago, I got an estimate for some AC and the HVAC guy and I discussed replacing the furnace. Typically, in this area, people have replaced floor furnaces with wall mounted units. All this guy wanted to sell me was a split unit and to heat with electricity, which, with the price of natural gas, is insane. Two more estimates, same basic idea. I don't know why they don't have more imagination. I guess I'll have this go-around when I get the furnace done. I never did install AC.
 

lou-in-usa

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I know a civil engineer in California who tells me that by state law, all new construction will only have electric appliances, including heat. Do you know if this applies to retrofits?
 

tmiskimen

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And this is the same state that shuts off your electric when the wind blows:oops:
 

NeilG

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I know a civil engineer in California who tells me that by state law, all new construction will only have electric appliances, including heat. Do you know if this applies to retrofits?
I don't know about new construction, but I can buy gas furnaces at HD, so I'd guess it's allowed for retrofits. I hope it's not true for new stuff. No sane cook wants to use an electric stove.
 

BuzzLOL

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I know a civil engineer in California who tells me that by state law, all new construction will only have electric appliances, including heat. Do you know if this applies to retrofits?
About 40 years ago here in N.W. Ohio they weren't allowing new gas customers so all the new housing developments were using electric heat... but electric costs 4 - 10 times as much to heat with as natural gas... Natural gas went way up for a while, but is now, amazingly, back down to 40 years ago prices!
 

tomtheelder2020

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lou-in-usa, as a resident of CA and after some Google searching, I conclude your friend's information sources should not be trusted. As best I can tell, he is referring to SB 49 (2019) which requires the CA Energy Comission to "foster the development of smart appliances that can shift demand for electricity to when renewable power production is at its peak." That law passed the Assembly by (60-15) and the Senate by 31-9. so it seems not terribly controversial.
 

68bucks

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About 40 years ago here in N.W. Ohio they weren't allowing new gas customers so all the new housing developments were using electric heat... but electric costs 4 - 10 times as much to heat with as natural gas... Natural gas went way up for a while, but is now, amazingly, back down to 40 years ago prices!
I don't remember a time when they weren't allowing new gas customers. I'm 60 so I hadn't purchased my 1st home yet so maybe that's true. I know in that period a lot of homes were going all electric it was the popular thing. Both my kids have total electric homes. Told them they were crazy to buy an all electric home but they did. 40 years ago we used fuel oil as did a lot of people, every home my parents ever owned was oil heat. Just about 40 years ago oil went through the roof, relatively speaking so a lot of people went electric it was cheaper cleaner and simpler depending on the system you used. Forced air electric is the worst. NG is not available to a lot of people especially rural. NG went up with demand but fracking produces a ton of NG in conjunction with the oil so supply is way higher along with new tech to produce, handle and ship LNG. Thats why NG prices are what they are, over supply. Same reason all these small NG powered electric generation plants have popped up. Some day NG will get expensive again and that electricity will go right with it Un less renewable can fill the gap at a good cost.
 

Fireguy5674

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In the early 70's in central Illinois they were not allowing any new NG services. I believe it was a concern over supply. However, when I built a home in '79 I was able to get it.
 

BuzzLOL

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Gas, gasoline, and oil went way up again while BushJr. was president. At the end of Pres. Clinton, crude oil was $9.99/barrel. By the end of BushJr. in 2008 it was $157.00/barrel and gasoline was $5/gal., $6/gal. in California and Hawaii. Nat. Gas $1.20/CCF. Now I pay about 35c/CCF for Nat. Gas because Pres. Trump insisted that USA become self sufficient on energy, but Pres. Biden has already taken steps to quickly end that.
 

68bucks

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Gas, gasoline, and oil went way up again while BushJr. was president. At the end of Pres. Clinton, crude oil was $9.99/barrel. By the end of BushJr. in 2008 it was $157.00/barrel and gasoline was $5/gal., $6/gal. in California and Hawaii. Nat. Gas $1.20/CCF. Now I pay about 35c/CCF for Nat. Gas because Pres. Trump insisted that USA become self sufficient on energy, but Pres. Biden has already taken steps to quickly end that.
By this chart I found it looks like residential NG prices peaked from about 2006 - 2008 then dropped sharply until about 2013-20016 but has remained relatively flat since 2013. That is about what I experienced on an industrial basis at a manufacturing plant that I worked at. Gas saving projects were a big deal from the 1980's until about 2010. After that point projects that had NG savings potential were never ignored but dropped a lot in significance. I wish I has NG at my house. At least in this day it makes fuel choice sort of a no brainer, but alas I'm stuck in propane land.
 
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