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  1. #1
    Join Date
    Jul 2012
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    6

    4 Ton Air Handler for 1800 Sq Ft?

    I have an 1800 sq ft ranch in New Jersey built in 1960. Unfinished attic has about 8" insulation and windows are newer thermopane but I am not sure if walls are insulated. Has a fair amount of large windows. It sits mostly over a full basement with two foundation walls exposed (walk out). Has forced air heat with 3 ton air handler. Central a/c (3 ton) is run through the heating ducts as well. Furnace is 18 years old and a/c is 16, both are Carrier. I am having difficulty cooling the house this year. Air temp just above evaporator coils is around 60 degrees, tech says should be closer to 50. Tech says refrigerant is good and rest of systems checks out but compressor line pressure is high and is running hot. One of the issues is that air flow at supply registers is weak and I don't see how it can keep the house cool in 95 degree weather. I took the air filter out temporarily but it didn't seem to make a difference. I am running a couple of vortex fans in front of registers to help distribute air up and across the rooms. Blower in furnace seems to be fine. I am going to replace the a/c and possibly furnace as well. Tech says to upgrade to 4 ton air-handler to increase duct pressure. Does this seem like too much for 1800 sq ft?

  2. #2
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,956
    Quote Originally Posted by scotzz View Post
    I have an 1800 sq ft ranch in New Jersey built in 1960. Unfinished attic has about 8" insulation and windows are newer thermopane but I am not sure if walls are insulated. Has a fair amount of large windows. It sits mostly over a full basement with two foundation walls exposed (walk out). Has forced air heat with 3 ton air handler. Central a/c (3 ton) is run through the heating ducts as well. Furnace is 18 years old and a/c is 16, both are Carrier. I am having difficulty cooling the house this year. Air temp just above evaporator coils is around 60 degrees, tech says should be closer to 50. Tech says refrigerant is good and rest of systems checks out but compressor line pressure is high and is running hot. One of the issues is that air flow at supply registers is weak and I don't see how it can keep the house cool in 95 degree weather. I took the air filter out temporarily but it didn't seem to make a difference. I am running a couple of vortex fans in front of registers to help distribute air up and across the rooms. Blower in furnace seems to be fine. I am going to replace the a/c and possibly furnace as well. Tech says to upgrade to 4 ton air-handler to increase duct pressure. Does this seem like too much for 1800 sq ft?
    I have to go somewhere for the day, so will be very brief.

    First, air flow has to be bought up to specs & ducts sealed. It needs at least 1200-CFM of air flow through that indoor coil for 3-Ton of cooling...

    It also appears there maybe major refrigerant system problems that must be addressed...After the airflow & duct system

    Blower in furnace seems to be fine. I am going to replace the a/c and possibly furnace as well. Tech says to upgrade to 4 ton air-handler to increase duct pressure. Does this seem like too much for 1800 sq ft?
    FORGET WHAT I WROTE ABOVE!

    Do all the weatherization U can before having a room by room heat-gain heat-loss calc performed for sizing the ducts & the A/C.
    If U fix the duct system so it achieves .5" ESP at 1200-CFM U won't need a 4-Ton air handler or need high duct pressures to get adequate airflow.

  3. #3
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    AS mentioned above, weatherize and get a load calculation done first. IF you have descent insulation and not too many air leaks in the house, you might only need a 2.5Ton unit. Dropping a size might solve a lot of your problems. early 60's ranches are hit or miss on insualtion and number and size of windows and shading... so you really need a proper load calculation done.

  4. #4
    Join Date
    Jul 2012
    Posts
    6
    Where can I find info how to calculate heat gain/loss? House does get pretty decent shade in the afternoon so, it is not fully exposed to sun. I checked ductwork where exposed and don't see any real leaks. Airflow from registers closest to air handler to those furthest away seem more or less equal.........no dramatic difference. Just seems weak everywhere. I do need to check blower for lint build up. How I can I tell if the blower is putting out the proper amount of cfm for its rating?

  5. #5
    Join Date
    Jun 2007
    Location
    Greenwood Indiana (Indianapolis)
    Posts
    420
    Quote Originally Posted by scotzz View Post
    Where can I find info how to calculate heat gain/loss? House does get pretty decent shade in the afternoon so, it is not fully exposed to sun. I checked ductwork where exposed and don't see any real leaks. Airflow from registers closest to air handler to those furthest away seem more or less equal.........no dramatic difference. Just seems weak everywhere. I do need to check blower for lint build up. How I can I tell if the blower is putting out the proper amount of cfm for its rating?
    I would get a second opinion. Probably needs cleaned. Replace the filter with an inexpensive one for a test, one that you know won't slow down air flow.

    Most companies do a heat loss/gain program.
    Rule of thumb is 700 sq. ft. per ton.
    Last edited by Kevin Weaver; 08-02-2012 at 02:31 PM. Reason: adding info
    As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

  6. #6
    Join Date
    May 2006
    Location
    Philadelphia, PA
    Posts
    1,378
    Did it work ok last year? Much of this summer has been at or above design temp for NJ.

    Follow the advice above. Get a second opinion about the current systems operation. Maintenance may be all that is needed for now. If it is working properly, you may buy some time to properly weatherize the house, then have a system designed and installed for it.
    Climate Control Solutions for your Home or Office

    Serving Northeast Philadelphia and Surrounding Areas

  7. #7
    Join Date
    Jul 2012
    Posts
    6
    Quote Originally Posted by comfortdoc View Post
    Did it work ok last year? Much of this summer has been at or above design temp for NJ.

    Follow the advice above. Get a second opinion about the current systems operation. Maintenance may be all that is needed for now. If it is working properly, you may buy some time to properly weatherize the house, then have a system designed and installed for it.
    I moved into this house last May and the system was definitely stronger. It would just about hold 75 on the hottest days (100+ with heat index). Last night when tech was checking, we let the unit run continuous for 1 1/2 hours while it was lightly raining with an outdoor temp around 76. Indoor temperature remained unchanged at 74. It was only when I turned the two vortex floor fans on that the temp went down to 72 in about 1/2 hour. I also checked my utility bill and this July, I used almost double Kwh what I used for July 2011. According the the bill, July this year was an average 2 degrees cooler than last year. .The same comparison for June 2012 vs June 2011 shows 30% more energy this year for an average of 4 degrees less. Billing cycle is through the middle of the month, not the end. I have gas for almost everything in the house so the only big item is the a/c.

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,870
    Since you had good air flow last year. Its not a system size problem. The tech you had out just doesn't know what to check.

    Did he check SH and SC?
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  9. #9
    Join Date
    Jul 2012
    Posts
    6
    Quote Originally Posted by beenthere View Post
    Since you had good air flow last year. Its not a system size problem. The tech you had out just doesn't know what to check.

    Did he check SH and SC?
    I didn't feel that air flow last year was better but I didn't have the cooling issues I am having this year. Tech says refrigerant is good (I had the system serviced in May) and line pressure is on the high side (200psi). He says high pressure indicates some leakage in the compressor and it is working harder. I am guessing the main problem this year is that air temp coming off the evaporator is 60.......tech says it should be 50.

    What is SH and SC?

  10. #10
    Join Date
    May 2006
    Location
    Philadelphia, PA
    Posts
    1,378
    You need someone to inspect the system properly and determine why it is not cooling. There are situations where the 60 leaving air temp would be normal.

    There are temperature and pressure readings a professional tech needs in order to make a proper diagnosis and repair recommendation.
    Climate Control Solutions for your Home or Office

    Serving Northeast Philadelphia and Surrounding Areas

  11. #11
    Join Date
    Jul 2012
    Posts
    6
    Quote Originally Posted by comfortdoc View Post
    You need someone to inspect the system properly and determine why it is not cooling. There are situations where the 60 leaving air temp would be normal.

    There are temperature and pressure readings a professional tech needs in order to make a proper diagnosis and repair recommendation.
    Can anyone recommend someone who is good in North Jersey?

  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,870
    Quote Originally Posted by scotzz View Post
    Can anyone recommend someone who is good in North Jersey?
    Click on the link in my sig, and see if one of our members services your area.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  13. #13
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,721
    Guys, NJ has a pretty serious program.

    $2, 4, and 6k rebates, low cost financing, etc...

    Scotzz. Check this out: http://www.njcleanenergy.com/hp/
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

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