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I Really Didn't Need This Just Now
We've been considering having our Carrier 58GP gas furnace inspected before winter swoops upon us. It has been working well for us for years but it was overdue for a routine inspection & general cleaning; it turns 24 tomorrow so it probably needed some TLC. Last week, I finally telephoned the original vendor of the furnace and scheduled an appointment. That happened today, and it wasn't pretty.
When the technician removes the front panel and immediately says "Uh oh," you know you have problems.
Immediately, he could see the pilot light was the wrong colour: it was bright orange instead of faint blue, indicating the feed to the light is partly clogged or restricted in some fashion.
Using a hand-held device with an extension shining a red light, he probed connections in the gas feed to look for leaks. The pipes to the furnace and all of the internals except for the control valves were OK; the control valves had a faint leak but that's not unexpected for a furnace this old.
The bad news worsened once we started up the furnace.
This type of gas furnace is allowed to have carbon monoxide emissions up to 400 parts per million (ppm) in the first minutes of igniting; once warmed up, CO should not exceed 100 ppm. Ours immediately spiked to over 2400 ppm and never dropped. Seriously not good.
Looking down at the individual bays of gas burners, it was clear that bay #2 wasn't fully lighting. We could see a couple inches of flame along the burner nearest the front but the back 10-12" were entirely unlit, indicating either a blockage or a crack. Even presuming one could find a suitable replacement for a system this old, it would cost $1600-$1800 USD to replace. Ouch.
The technician turned off his devices and the furnace and then gave me the dreaded news: county codes and his county licensing require him to turn off the furnace entirely and inform us it was not to be used until it was repaired or replaced.
We knew the furnace was old and inefficient, but I was at least hoping it would be fine until we could replace it at convenience in 2011. After absorbing a number of large financial hits from the extended family over the past year, we were finally making headway and I wanted to get our finances entirely under control before making large capital expenses. Clearly, it is not to be.
We were able to make an appointment with an estimator for this afternoon to look at options. We were considering replacing the furnace with a high efficiency unit which would meet the regulations for a $1500 USD tax credit from the federal gov't as well as a $500 credit from Maryland. Unfortunately, the additional duct & chimney work required for such a furnace would absorb the entire credit and a further $2k. A high efficiency unit would require a separate air intake from outdoors as well as a separate exhaust conduit; since the exhaust would be redirected from the chimney, it would place our gas water heater out of compliance so we'd need to line the chimney to stay within code.
Our next best option was to purchase an 80% efficient 100,000 BTU Amana/Goodman AMV8 model. We could use the existing chimney & duct work, we still get a more efficient unit that our current system and the variable speed fan system will work well with our current digital thermostat. For $4,600 USD, we get the permits, a new furnace, disposal of the old beast, a new condensation pump & external drain, a whole-house humidifier system (Honeywell HE265-A bypass) with its own condensate pump, an upgrade for code compliance for the water heater's exhaust (3" duct work replaced with 4") and a 10 year parts & labor warranty with lifetime warranty on the heat exchanger. The new toy should arrive for installation Monday morning.
I really didn't want to spend $4,600 USD right now, but there's no denying the old beast was reaching the end of its life. At least we'll have a replacement before winter arrives and we got what I believe to be a decent deal.
When the technician removes the front panel and immediately says "Uh oh," you know you have problems.
Immediately, he could see the pilot light was the wrong colour: it was bright orange instead of faint blue, indicating the feed to the light is partly clogged or restricted in some fashion.
Using a hand-held device with an extension shining a red light, he probed connections in the gas feed to look for leaks. The pipes to the furnace and all of the internals except for the control valves were OK; the control valves had a faint leak but that's not unexpected for a furnace this old.
The bad news worsened once we started up the furnace.
This type of gas furnace is allowed to have carbon monoxide emissions up to 400 parts per million (ppm) in the first minutes of igniting; once warmed up, CO should not exceed 100 ppm. Ours immediately spiked to over 2400 ppm and never dropped. Seriously not good.
Looking down at the individual bays of gas burners, it was clear that bay #2 wasn't fully lighting. We could see a couple inches of flame along the burner nearest the front but the back 10-12" were entirely unlit, indicating either a blockage or a crack. Even presuming one could find a suitable replacement for a system this old, it would cost $1600-$1800 USD to replace. Ouch.
The technician turned off his devices and the furnace and then gave me the dreaded news: county codes and his county licensing require him to turn off the furnace entirely and inform us it was not to be used until it was repaired or replaced.
We knew the furnace was old and inefficient, but I was at least hoping it would be fine until we could replace it at convenience in 2011. After absorbing a number of large financial hits from the extended family over the past year, we were finally making headway and I wanted to get our finances entirely under control before making large capital expenses. Clearly, it is not to be.
We were able to make an appointment with an estimator for this afternoon to look at options. We were considering replacing the furnace with a high efficiency unit which would meet the regulations for a $1500 USD tax credit from the federal gov't as well as a $500 credit from Maryland. Unfortunately, the additional duct & chimney work required for such a furnace would absorb the entire credit and a further $2k. A high efficiency unit would require a separate air intake from outdoors as well as a separate exhaust conduit; since the exhaust would be redirected from the chimney, it would place our gas water heater out of compliance so we'd need to line the chimney to stay within code.
Our next best option was to purchase an 80% efficient 100,000 BTU Amana/Goodman AMV8 model. We could use the existing chimney & duct work, we still get a more efficient unit that our current system and the variable speed fan system will work well with our current digital thermostat. For $4,600 USD, we get the permits, a new furnace, disposal of the old beast, a new condensation pump & external drain, a whole-house humidifier system (Honeywell HE265-A bypass) with its own condensate pump, an upgrade for code compliance for the water heater's exhaust (3" duct work replaced with 4") and a 10 year parts & labor warranty with lifetime warranty on the heat exchanger. The new toy should arrive for installation Monday morning.
I really didn't want to spend $4,600 USD right now, but there's no denying the old beast was reaching the end of its life. At least we'll have a replacement before winter arrives and we got what I believe to be a decent deal.
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Any chance some of that CO was getting in your house?
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Almost certainly. The accumulated brain damage might explain the lack of Nobel prize trophies on the mantle and/or my propensity to give money to needy family members.
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Seriously, do something about that old CO emitting furnace.
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a) good that you're getting it replaced NOW instead of in the middle of January, when "I'm afraid county codes require me to shut it off completely" would make for a rather rushed purchase of a replacement, not to mention a seriously chilly house in the interim; and
b) it's a good thing that you found out about the carbon monoxide. Those codes are in place to protect you, and CO is lethal. We'd all hate to have been reading about you as headlines in a "local residents killed by their furnace" story. Despite your headline, you really DID need that furnace taken out of your lives right now.
c) if you want to draw some financial balm out of this: assume your old furnace had lasted until spring 2011. How much gas would you have burned? Given (i) its general inefficiency (that particular model) and (ii) particular problems (burning with yellow flame = incomplete combustion = not as much energy out of the gas consumed as you might have had), you'll actually save $$ just on this winter's gas consumption.
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