Carrier Infinity Furnace Heat exchanger shot

[Cropduster172]

Was getting error codes for limit switch. It's an 11 year old Carrier Infinity. The tech. came out, cleaned the burners and showed me the flame roll out.
It's the heat exchanger...no argument.
Question is do you pay to replace the heat exchanger or get a new furnace?
AC is fine...so it's just the furnace.
AFUE 90.
Carrier does warranty the heat exchanger but is adamant about proving routine service which I can't do as we've only been here a year and no service records left fo the HVAC system.
My inclination is to replace the furnace with a mid level with fewer bells and whistles...a Bryant or Payne....both Carrier brands.

 

[wag123]

Heat exchanger shot in only 11 years? I would be looking at another brand.

 

[dishdude]

How much is the heat exchanger vs. system replacement?

 

[jeepman3071]

Heat exchanger shot in only 11 years? I would be looking at another brand.

11 years is considered the life of many modern units unfortunately.

 

[Cropduster172]

How much is the heat exchanger vs. system replacement?

Waiting on that estimate. Got pricing for replacement furnaces.
I won't go top of the line Carrier Infinity...not for a 3 BR townhome. I'm looking at middle of the line Payne if I replace. If it's $2500 to replace excgange and $4700 to replace the furnace, I'll get a new furnace.
The price difference seems to be 1 or 2 stage gas valves and variable speed motors vs single or 2 speed ones.

 

[tmorris1]

I have had really good luck with Lennox at both of my houses. At the current house I replaced the 33 year old Lennox in 2009 (New A/C and furnace) and I haven't touched it since. I have them check it every year or 2, but it hasn't missed a beat. It has the variable speed DC fan that runs continuously all winter.

 

[mightymousetech]

Going to a variable speed motor will pay for the upgrade in electricity cost alone.

 

[slug_bug]

The heat exchanger was replaced on my Lennox furnace due to a recall 24 years ago. Furnace is still running great with no issues.

 

[tmorris1]

Going to a variable speed motor will pay for the upgrade in electricity cost alone.

I noticed that immediately. They told me the DC drew about 60W and my old AC squirrel cage motor was about 500-600 Watts. So quiet too, all you hear is air.

 

[Cropduster172]

If I decide to go new furnace, am currently thinking the Payne with the 2 stage gas valve and variable speed motor....$5700.
Will find out about heat exchanger price later today.

 

[Oily_Thing]

I sure would not go back to Carrier or it's lower-quality sub brands.

 

[Cropduster172]

I sure would not go back to Carrier or it's lower-quality sub brands.

Carrier and it's brands have the best warranty and parts availability in the business. Also, the AC is Carrier...not sure if that will matter.
Also, have a Payne in our beach house that has been a work horse.

 

[ecotourist]

My inclination is to replace the furnace with a mid level with fewer bells and whistles...a Bryant or Payne....both Carrier brands.

11 years doesn't sound like very good service to me.

I'm not sure I buy the requirement for proof of regular service to get warranty coverage. How exactly would lack of regular service hurt a heat exchanger?

After that run around why would you even consider Carrier sub-brands? Do you expect them to be better than Carrier? As good, even?

 

[mk378]

If the A/C coil is above the furnace, it can drip water onto the heat exchanger and cause premature rust out. Look for that upon disassembly.

 

[tmorris1]

If the A/C coil is above the furnace, it can drip water onto the heat exchanger and cause premature rust out. Look for that upon disassembly.

Isn't that how every furnace is?

 

[Cropduster172]

Isn't that how every furnace is?

Yeah...I'm pretty sure that's nonsense.

 

[tmorris1]

Yeah...I'm pretty sure that's nonsense.

I'm no HVAC guy, but I think that is the only way I have ever seen it. The A coil is above the furnace heat exchanger and I think they are all stainless steel now too.

 

[manicrodder]

Isn't that how every furnace is?

It is for every furnace that's an up flow. Dripping condensation could occur if the tray which is integral to the evaporator is damaged or blocked but that's rare. I never had that happen In my 16 years in the trade.
The spray nozzle type humidifiers are a different story. Seen plenty of those corrode exchangers.

 

[UncleDave]

Seems to be a common failure.

My companies owner has had 2 fail in 12 years.
Its a great brand otherwise and fine performing equipment.

That said-

If Id buy again Id go Lennox again- the signature series gear has been fantastic.

 

[wag123]

If the A/C coil is above the furnace, it can drip water onto the heat exchanger and cause premature rust out. Look for that upon disassembly.

The OP has a High-Efficiency Condensing Furnace which has two heat exchangers. The problem with some of these is the condensation that forms in the secondary heat exchanger causes it to corrode. As the gases cool, they condense to form water and carbon dioxide which together form carbonic acid. The water (called condensate) drips out through a drain pipe, and the remaining flue gases are vented to the outdoors through a plastic pipe. Carrier has had a lot of problems with this going back at least 25 years, and they have lost several class action lawsuits because of it. The solution to this problem is to switch to a manufacturer's product that doesn't have this problem or use a lower 80-83% efficiency furnace that only has one heat exchanger.
Also, I personally have a problem with a manufacturer that requires an annual service by an authorized dealer to keep their warranty in effect (and this applies to ANY product).