Interesting find

Drove by this house for sale. First time I’ve seen this.
Has anybody else seen this before?

Looks like they ran the vents for the new high efficiency system up an old chimney chase.

Yep. About 20% of the time with old homes. They got rid of an old, inefficient furnace and installed a new high efficiency furnace. Why drill holes in the side of the house? Hope they still put a cap over the rest and sealed the chimney.

One would think that putting the intake and exhaust on the side of the house would be better. I figure many older homes have chimneys in rough shape and removing the chimney would keep the house warmer by getting rid of the stack effect.

Yes a few and I see nothing wrong with doing this .Great way to do it.

Looks like an add for Viagra, before n after pics…

Totally wrong! If this is for a high efficiency furnace it won’t work. The low temperature of the HE furnace exhaust will not have sufficient buoyancy to make the trip up the old chimney. That is why they are vented out the side of the house. Improper installation.

Please post one, just one, installation manual or manufacturer that substantiates your claim. It is common and allowed. The only difference is that when installed this way, in any exterior portion of chimney, the exhaust vent must be insulated.

Stephen, you go first show me an installation manual that say it is okay to vent a HE furnace up a 2 story house brick chimney.

Looking further it looks like it is not allowed.
No way to support the pipes inside the chimney for one thing .
I could not find any place where it is a recommended method.

I looked at the first one that came up on Google. Lennox High Efficiency Model EL296E. No issues. Approved to vent through the chimney as long as the vent is the proper size. See Figure 46, and Table 5 for the allowable length of the vent pipes and number of 90’s allowed.

Your turn.

http://www.thermopride.com/pdf/422690I%20TPace-VSAInstallersManual.pdf

Not only is vertical venting allowed, it’s preferred. There is a chart for pipe length as well you can look at.

Ah. Stephen beat me too it.

http://www.crownboiler.com/documents/90_Series_UCA_Installation_Manual.pdf

I agree with Juan. Vertical installation is the preferred installation.

Here is a another link that sees no issue with the vent pipe in an abandoned chimney as long as the top is properly capped.

http://www.totalairsupply.com/files/9%20November%2007%20Venting%20&%20Draining%20Condensing%20Furnaces.pdf

If it’s power vented, how does buoyancy matter?

Gerald… still waiting for your response… yoo hoo… :wink:

Spoke too soon. :slight_smile:

Stephen, check table 7 in your example manual. The vertical lengths are very much limited by the minimum cold temperature as there is no visible insulation in the picture I stand by my comments.

NOTE

  • See table 7 for maximum allowed exhaust pipe
    length without insulation in unconditioned space during
    winter design temperatures below 32°F (0°C). If required
    exhaust pipe should be insulated with 1/2” (13mm) Arma*
    flex or equivalent. In extreme cold climate areas, 3/4”
    (19mm) Armaflex or equivalent may be necessary. Insula*
    tion on outside runs of exhaust pipe must be painted or
    wrapped to protect insulation from deterioration. Exhaust
    pipe insulation may not be necessary in some specific ap*
    plications.

Look at Table 7 in the manual your reference, the exhaust length are limited for no insulation of piping. I see no insulation in the picture and stand by my comments.

NOTE

  • See table 7 for maximum allowed exhaust pipe
    length without insulation in unconditioned space during
    winter design temperatures below 32°F (0°C). If required
    exhaust pipe should be insulated with 1/2” (13mm) Arma*
    flex or equivalent. In extreme cold climate areas, 3/4”
    (19mm) Armaflex or equivalent may be necessary. Insula*
    tion on outside runs of exhaust pipe must be painted or
    wrapped to protect insulation from deterioration. Exhaust
    pipe insulation may not be necessary in some specific ap*
    plications.

I have become friends with a chimney sweep from the Netherlands with a 4 year degree and many years experience. His question is this. How do you keep the moisture out of the chimney? No rain cap and not a good idea to seal with mortar. So easy access for flue but bad for the chimney?

Why is mortar a bad idea? I see the vents and combustion air pipes through brick walls or foundation walls all the time. Is there something bad about applying a mortar crown around the pipes?