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old unico

No, this has yet to be done. But if all these measurements were obtained and found to be ok, I'm thinking that the system components are approaching 20 years and it may be reasonable to update. It really 'frosts' me to have the system run for hours with only a degree or two drop.


  • Dave_4
    Dave_4 Member Posts: 1,405
    old unico

    have received excellent advice from heating side, now have a/c question. Have a 1990 install of hp4860 (27 outlets/6" square fiberglass main) on third floor and vp2436 (17 outlets) in basement with trane xe800 condensers. both, esp the third floor are very WEAK in terms of airflow and cooling (4 hours to reduce inside temp 81 to 80 when outside 89) compared to new unico installs in neighborhood (cleveland area). removed filters with no resultant change in airflow; recharged coolant with barely noticeable change. 4860 losing coolant. if plan on staying here ~ 10yrs., would you replace system. one HVAc suggested also replacing main trunk with larger diameter to accomodate increased airflow. but, according to old spec sheets, 4860 rated up to 920 cfm, new 4860 is 1250 cfm. would potential 36% change in cfm require this extra puch-up. any advice welcome. thanks
  • don_192
    don_192 Member Posts: 45
    Hello Tony

    I would have to ask, have you ever had the coils and blower cleaned on your system?

    Has the airflow always been a issue in the area you mention
    or has it just gotten worse over the years?

    Has the static pressure ever been tested and compare to a fancurve to see if you were getting spec cfm out of the system.

    Dirty coils,blower wheels,filters,and even collaspe duct work can reduce your cfms.

  • Dave_4
    Dave_4 Member Posts: 1,405

    Don, thanks for response. Coils cleaned 2 years ago; filthy now. Blower 'looks' clean, but not cleaned to my knowledge. Airflow unchanged since we moved in 5 years ago as is the ability of the system to reduce temperature. Crawled along main duct in crawlspace (checking for leaks), no evidence of extrinsic compression. Main has T with a 35' and 100' run. (House is about 5,200 sq ft divided equally between 1st and 2nd floors built in 1915; attic insulated best as possible.) There is an electric heating element (use occaisionally if Fall); maybe this contributes to reduced airflow. No, pressure test not performed.

    1. If someone were to clean the components, how would they compare to a new condenser/air handler; would it be a significant difference?. 2. If worth replacing, would the main duct have to be replaced with larger diameter?

    p.s. After reading Dan's book on steam heating, it was easy to sort the competent contractors. I do not feel so comfortable in speaking with a/c contractors. Any information you could direct me to is appreciated. Thanks.
  • don_185
    don_185 Member Posts: 312
    Checkout information.Also go to the on line store and find the book called Bobs House.That should answer any question you might have.

    Mr Holohan,I know its consider rude to post another site while on this site or any other site for that matter.

    Please delete if thats the case.

  • schiller
    schiller Member Posts: 60

    Tony, the 4860 is the inside unit rating (4 to 5 tons) it would be helpful to know the out door unit (condenser) capisity (tonage) typicaly unico systems have 5 to 6 outlets per ton. so if you have a 5 ton unit you should be ok, if you have only 4 tons then you have found your problem. if the air handler is working then the air must go some where or the coil would freeze. I suspect that you have few few things happening at once but a good tech should be able to help. if its 17 years old it might be time to up grade. we like the unico product over the out H.V. unit seems to be more quite. I'd love to help but given that you are in buckeye land maybe that's how they do it. go blue!
  • Dave_4
    Dave_4 Member Posts: 1,405

    Don and Schiller: Appreciate info/lead. Original worksheet left with previous owners shows that installer determined that 90,000 BTU cooling required based on sq ft calcs and placed 4 ton unit in attic (for 2nd floor, which includes open stairway) and 3 ton unit in basement for 1st floor. Realize that 17 yr old equip may have seen its day. I'm hung up on main vent size as well as fiberglass vs wrapped sheet metal, if existing 6' square fiberglass had to be replaced.
  • Brian_56
    Brian_56 Member Posts: 7
    Unico Help


    We are a HVAC contractor in the Cleveland area specializing in hot water/steam and Unico systems. I would be happy to come out at no charge to take a look at your system to see how we can help you.

  • heatboy
    heatboy Member Posts: 1,468
    I ws just going to.........

    ........mention this gentleman call you, Brian. Give your dad my best and I would love to see him at the RPA in Hartford.


    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

    The Radiant Whisperer

    "The laws of physics will outweigh the laws of ecomomics every time."
  • Jim Pompetti
    Jim Pompetti Member Posts: 552

    Have you done a sub cool and what is the coil temp , what is the cfm
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