Would it be worth it to disassemble and clean an older furnace?

The furnace in question is approximately 20 years old, and has never been serviced...

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-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.

Yes.

If this is a typical central unit then not only will the burner orifices need to be cleaned but the heat exchanging unit above them.

There will be a great deal of black soot to deal with. Wear a face mask which are available at any hardware retailer.

There are long brushes that are made just for this type of work.

You might also scour the internet for instructions. The work is not hard, but you want to do it right if you are in there.

Don't use canned air to clean it with...I know a guy we call "Crispy" that is permanently scarred from the resulting explosion.

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1987 560SL
85,000 miles

Just buy another furnace.

Get some 1000cc/min injectors and a Megasquirt controller

Sixto
87 300D

And lower the chimney. Hellaflush chimney!

This may be the best suggestion you will receive. Changing out a furnace unit is not difficult, and the advances made in furnace tech over the past twenty years might allow you to someday pay for the new unit in energy savings.

The ease of changing the unit out will vary depending on the unit and your skill level, but this is an option that should not be dismissed out of hand.

Your municipality might require a permit to replace the furnace and/or a license to perform the job. There might be new codes in effect when you replace the furnace. We faced all that some years ago when we replaced our water heater with a seemingly identical one.

Sixto
87 300D

What they don't know, won't cost you....

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On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif

The downside to a new furnace is that it likely to be more complicated than the one you have and more difficult to maintain by the DIY.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

If you choose to go the replacement route, opt for a 90%-92% efficiency unit. We have seen hundreds of the "high efficiency" units (93% and over) installed over the past few years through various government sponsered energy conservation programs and can say unequivically that if you go for one of these you will probably be sorry.

Bottom line is that they are totally electronically controlled and you will spend many times what you might save in fuel costs replacing "boards" that seem to crap out within minutes of the warranty expiration.

All of the HVAC contractors that we work with tell the same tale. They see the high efficieny units as a royal PITA and will usually recommend the low 90% class.

Jim

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2005 C240 4matic wagon (daily driver)
87 190D - 225K (on loan)
85 190D - 312K (on loan)
2011 Subaru Legacy AWD (Wife's)

Exactly what I was thinking about. The best is a simple gas valve, pilot, thermocouple, limit switch and a thermostat.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

A gas furnace shouldn't need much cleaning. Other than built up dust. The gas burns clean and the burners need little attention. If the furnace runs well, give it a once over and drive it till it dies. A newer furnace will take a long time to pay back the expenditure.

Mine is a 92% efficiency and its electronically controlled in every way, has been working fine for years with no repairs, when really cold it runs 6-7 hours a day. My father in law has a 99% efficiency furnace and its got to be at least 10+ years old by now, no issues either. The fuel savings add up real fast, especially up here where its super cold for a good portion of the year.

Best idea would be to replace it with the highest quality highest efficiency unit you can reasonably buy, with a nice long warranty.


Compared to a car even the electronic furnaces are technologically simple, just sensors and a control board....not really that hard to work on if something goes wrong. Mine has a huge thick manual with all the error codes (board has LED's to blink the issue like a car would)

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

There shouldn't be any soot in a gas furnace, or an oil furnace either, for that matter. If there is, you have another problem beyond normal cleaning.

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'83 300D, 126K miles.