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  1. #1
    Join Date
    Jan 2006
    Location
    Minneapolis, MN
    Posts
    70
    First, thanks to all of the very helpful people I have heard from on this forum on a variety of posts! You have really helped me out on a major purchase!

    Finally, maybe my last question. I recently had a Rheem Modulating furnace installed in my home. In the install, they patched into an existing 2" vent. The setup is 3" PVC from the furnace through an elbow to a 3"-2" contraction, then into existing 2" pipe. All looks very nice, except I noted from reading through the installation manual (I am a nerd about such things), it is stated that there should be no longer than a 10' run of 2" pipe when there are 5-6 elbows (for the 75,000 BTU furnace). Due to an awkward location of the furnace in my home, the exisitng 2" vent run has 6 elbows and runs for a total of at least 20 feet. So, the new vent line has about 12 feet of 3" pipe including one elbow then about 20 feet of 2" pipe with 6 elbows.

    I asked about this and got answers I didn't like. I was told (1) that they had installed far longer 2" runs for this furnace with no problems, (2) that the pressure-limiter switch would keep the furnace from running if there were a venting problem, and (3) since most of the run is vertical it's not a problem.

    I worry that (1) the existing setup, though easy to install, clearly violates the guidelines in the manual, (2) will this shorten the vent blower life?, and (3) is this a safety hazard?

    Am I being too concerned? What is a good way to proceed?

    Thanks again!

  2. #2
    Join Date
    Jul 2004
    Location
    midwest
    Posts
    2,868
    They need to install it exactly like the install instructions say and no different. If what you say is correct the pressure switch could be on the edge of making or not and any change in wind or many other conditions might leave you with no heat. If anything I always go bigger when its close on the total length after finding out that some furnaces will not work under certain conditions when the length is pushed to the maximum allowed.

  3. #3
    Join Date
    Oct 2002
    Location
    pleasant prairie wi
    Posts
    246
    got any pics???

    so they started 3" at the furnace and reduced to 2" before it terminated???
    LOVED BY FEW, HATED BY MANY!!!

  4. #4
    Join Date
    Feb 2006
    Location
    Omaha, NE
    Posts
    1
    Your installation instructions show a max vent length of 10' with 6 elbows. You have 20' of 2". The furnace was not tested to operate outside of those parameters. You will have vent pressure switch problems

  5. #5
    Join Date
    Jul 2002
    Posts
    962
    They probably should have discussed this with you when they quoted the job. The problem now is who is willing to pay for this work. It sounds like they where trying to save you money and them some work. Why not offer to pay half of the cost to make it right?

  6. #6
    Join Date
    Jul 2004
    Location
    midwest
    Posts
    2,868
    Originally posted by Chill
    They probably should have discussed this with you when they quoted the job. The problem now is who is willing to pay for this work. It sounds like they where trying to save you money and them some work. Why not offer to pay half of the cost to make it right?
    I disagree with this line of thinking. They Should know what is required and they should have included everything in their bid to install it according to the installation instructions.

  7. #7
    Join Date
    Dec 2005
    Location
    Cleveland, OH
    Posts
    2,125
    I was always taught never to reduce the size of a flue. Increasing OK, decreasing bad. I know some PVC flues reduce a size right before they terminate, but I can't see running 3" for such and such a length and then reducing to 2".

    Sounds like you got a hack job. They probably don't want to fuss with the roof termination. I'd make them come back and do it the correct way, and I wouldn't pay another dime for it. You paid for a proper install, get one.

    Good? Bad? I'm the guy with the gun.

  8. #8
    Join Date
    Jul 2002
    Posts
    962
    Originally posted by trane
    Originally posted by Chill
    They probably should have discussed this with you when they quoted the job. The problem now is who is willing to pay for this work. It sounds like they where trying to save you money and them some work. Why not offer to pay half of the cost to make it right?
    I disagree with this line of thinking. They Should know what is required and they should have included everything in their bid to install it according to the installation instructions.
    I was just being open minded. There are two sides to every story. That could of been a legitamate oversite on the installers part. We don't know without being there to see for ourselves. It sounds like it could be alot of extra work. There are sometimes hidden costs that are not readily seen,and perfectly legal to adjust the quote for same.

  9. #9
    Join Date
    Jul 2004
    Location
    midwest
    Posts
    2,868
    Everyone looks at it different but I have NEVER charged someone for something I may have overlooked when bidding the job. My bids all say on them that this bid includes all equipment, parts, material, and labor to install the complete system.

  10. #10
    Join Date
    Jul 2002
    Posts
    962
    I guess your talking about new construction. I haven't had to charge for something I have missed either. However I have had customers(two exact)that have offered to pay more because they realized the great price I gave them and finding extra work on an old house(for example).

  11. #11
    Join Date
    Jan 2006
    Location
    Minneapolis, MN
    Posts
    70
    Originally posted by tinknocker11
    got any pics???

    so they started 3" at the furnace and reduced to 2" before it terminated???


    From furnace to sill. 3"-2" contraction circled. (2 elbows on the 3".)



    Closer up. The arrow points to sill. As it continues (out of sight), the 2" pipe turns 90 deg through sill, then 90 deg upward, then straight shot up through garage into attic, then two 45 deg elbows to roof vent. (Counting up, there are 6 elbows on this 2" pipe.)

    I am thinking that they could replace all 2" with 3" by drilling large holes and following same route. Then they could terminate in the attice to the 2" through the roof (OK by install instructions).

    This does not seem that hard to me. Heck, I think I could do it myself in 2 hours (but I won't... I will leave it to the pros).

  12. #12

    A picture

    I think the exciting installation will work, but since you are paying for it. You should get what you pay for.


    They should have use the clear primer instead of the purple it looks better.

    regards,
    Kelvin

    [Edited by klyons20 on 02-13-2006 at 09:43 PM]

  13. #13
    Join Date
    Jul 2004
    Location
    midwest
    Posts
    2,868
    I still agree with my first comments. It makes no sense to do what they did.

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