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  1. #27
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,111
    Quote Originally Posted by Cap'n Preshoot View Post
    The Tech *purposely* added addt'l coolant based on what he determined was low current draw. He had his manifold guages attached along with amprobe (which agrees w/mine) and incrementally added more coolant until the current draw got up to what he thought it should be (11.2 amps) while watching his gauges and stopping at 400 PSI..
    Ok, your a troll and this is a joke right?
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  2. #28
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,564
    Can't determine charge by amp draw. He should have used subcool, and checked the superheat.
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    How many times must one fix something before it is fixed?

  3. #29
    Join Date
    Sep 2009
    Location
    Arnold mo
    Posts
    3,977
    Quote Originally Posted by Cap'n Preshoot View Post
    You may have hit on something here... We recently had an alarm guy in the attic adding glass-break sensors in 2 bedroom ceilings. I just wonder what the chances are he might have accidentally gotten tangled up in a return air line? I guess an easy way to check that would be to see if we have good suction at both return air registers (MBR ceiling and hallway)
    These sensors are installed by cutting a hole in the ceiling? How much insulation was disturbed/pushed aside? Cutting holes in the ceiling and pushing insulation aside will increase your heat load. Some estimate that as little as 7% voids in insulation can reduce its R-value by as much as 50%. A sudden change in a/c performance and someone also happening to be in the attic is definetly worth checking to see if maybe one of the returns have been kicked off the main trunk line.
    An answer without a question is meaningless.
    Information without understanding is useless.
    You can lead a horse to water............
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  4. #30
    Join Date
    Jul 2005
    Posts
    5,576
    I think the OP is the tech. If not he should probably get another one asap.

  5. #31
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,025
    You don't check the charge or, charge by compressor AMP-DRAW.

    There is not enough test data to indicate that the TXV is bad; most data indicates it is working okay with the few other existing conditions listed.

    Want us to be enabled to check the ballpark performance of your system... so you can call an HVAC Contractor with some data with which to test the Tech's knowledge level?

    All U need is a good thermometer (digital reading in tenths preferable) & and indoor Humidity Gauge

    1) Helpful; Tonnage & SEER of Unit &/or outdoor condenser model number: Minimum SEER upped to 10-SEER in 1987

    2) TXV or, orifice metering device? TXV. Only if U know…

    3) Outdoor condenser’s discharge-air-temperature ______-F
    Subtract Outdoor air temperature: _______
    Outdoor Condenser Air-Temp-Split _______

    4) Need the ‘Indoor’ percent of relative humidity - in the middle of the rooms or, at Return-Air inlet grilles ________

    5) Indoor Return-Air Temperature ______
    Subtract Indoor Supply-Air Temperature ______ -F
    Indoor temperature-split _______-F

    If U can find a turn in the small liquid line insulate the temperature-probe; get its temperature for the subcooling analysis; tubing sensors are best:
    Small liquid line temperature ____F

    Need the above information for troubleshooting & performance analysis.

    Example below:
    A Goodman 2-Ton 13-SEER condenser, @800-cfm indoor airflow; 80-F indoor dry bulb & 50% relative humidity; Indoor temp-split 18 to 19-F.
    @ 85-F outdoors; 103.9-F - 85-F outdoors or around an 18.9-F temp-split;
    @Indoor 75-F, 63-wet bulb around 50% RH - condenser temp-split is only 14.9F.
    Last edited by udarrell; 08-19-2012 at 05:07 PM. Reason: with some data with which to test the Tech's knowledge level

  6. #32
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,808

    Confused

    Quote Originally Posted by Cap'n Preshoot View Post
    The Tech *purposely* added addt'l coolant based on what he determined was low current draw. He had his manifold guages attached along with amprobe (which agrees w/mine) and incrementally added more coolant until the current draw got up to what he thought it should be (11.2 amps) while watching his gauges and stopping at 400 PSI. This was the only way he was able to get the temp differential even close too what it should have been. I think he got it to around 12 deg. He said the current draw should have been 80% of RLA (14) rated amps. He was not happy with the result, which led him to believe that maybe the TXV was defective and wanted to come back another day (no add'tl svc call chg) to remove the TXV and put in a piston. Swapping the TXV for a Piston is what prompted me to come to this group for another opinion.
    O no he did not charge up the unit that way sounds like he lackes the basiscs ,you need a new tech

  7. #33
    Join Date
    Aug 2012
    Location
    Katy, TX
    Posts
    50
    Quote Originally Posted by Mr Bill View Post
    Ok, your a troll and this is a joke right?
    Unfortunately all is true. He was trying to get the temp diff up to at least 15 degrees and said that the differential being low and the current draw also being low suggested to him that it was low on coolant. When he left Friday he's now offering to come back on his own time off the clock & offered to sell me parts (a capacitor) at his cost. I really don't want the guy back out here.

  8. #34
    Join Date
    Aug 2012
    Location
    Katy, TX
    Posts
    50
    Quote Originally Posted by tipsrfine View Post
    These sensors are installed by cutting a hole in the ceiling? How much insulation was disturbed/pushed aside? Cutting holes in the ceiling and pushing insulation aside will increase your heat load. Some estimate that as little as 7% voids in insulation can reduce its R-value by as much as 50%. A sudden change in a/c performance and someone also happening to be in the attic is definetly worth checking to see if maybe one of the returns have been kicked off the main trunk line.
    Only a 1/4 in hole in the ceiling to push in a layup stick so he could fine it. The glass break sensors are just screwed into the sheetrock ceiling. We have what appears to be good suction on both return air lines, but today's much cooler weather coupled with the system suddenly working good today is admittedly suspect

  9. #35
    Join Date
    Aug 2012
    Location
    Katy, TX
    Posts
    50
    Quote Originally Posted by tipsrfine View Post
    These sensors are installed by cutting a hole in the ceiling? How much insulation was disturbed/pushed aside? Cutting holes in the ceiling and pushing insulation aside will increase your heat load. Some estimate that as little as 7% voids in insulation can reduce its R-value by as much as 50%. A sudden change in a/c performance and someone also happening to be in the attic is definetly worth checking to see if maybe one of the returns have been kicked off the main trunk line.
    Only a 1/4 in hole in the ceiling to push in a layup stick so he could find it in the attic. The glass break sensors are just screwed into the sheetrock ceiling. We have what appears to be good suction on both return air lines, but today's much cooler weather coupled with the system suddenly working good today is admittedly suspect

  10. #36
    Join Date
    Aug 2012
    Location
    Katy, TX
    Posts
    50
    Quote Originally Posted by udarrell View Post
    You don't check the charge or, charge by compressor AMP-DRAW.

    There is not enough test data to indicate that the TXV is bad; most data indicates it is working okay with the few other existing conditions listed.

    Want us to be enabled to check the ballpark performance of your system... so you can call an HVAC Contractor with some data with which to test the Tech's knowledge level?

    All U need is a good thermometer (digital reading in tenths preferable) & and indoor Humidity Gauge

    1) Helpful; Tonnage & SEER of Unit &/or outdoor condenser model number: Minimum SEER upped to 10-SEER in 1987

    2) TXV or, orifice metering device? TXV. Only if U know…

    3) Outdoor condenser’s discharge-air-temperature ______-F
    Subtract Outdoor air temperature: _______
    Outdoor Condenser Air-Temp-Split _______

    4) Need the ‘Indoor’ percent of relative humidity - in the middle of the rooms or, at Return-Air inlet grilles ________

    5) Indoor Return-Air Temperature ______
    Subtract Indoor Supply-Air Temperature ______ -F
    Indoor temperature-split _______-F

    If U can find a turn in the small liquid line insulate the temperature-probe; get its temperature for the subcooling analysis; tubing sensors are best:
    Small liquid line temperature ____F

    Need the above information for troubleshooting & performance analysis.

    Example below:
    A Goodman 2-Ton 13-SEER condenser, @800-cfm indoor airflow; 80-F indoor dry bulb & 50% relative humidity; Indoor temp-split 18 to 19-F.
    @ 85-F outdoors; 103.9-F - 85-F outdoors or around an 18.9-F temp-split;
    @Indoor 75-F, 63-wet bulb around 50% RH - condenser temp-split is only 14.9F.
    Thanks for your offer. I don't have a temp probe, just the gun and regular indoor/outdoor atomic clock/thermometers and a residential "Taylor" RH gauge built into a nice barometer/clock thermometer wall unit. I could probably pick up a temp guage at Lowes or ACE Hdwe like a meat thermometer, but for for regular temps not for cooking All my tools are for electrical and transmitter work & I got the IR temp gun more to play 'chase the dot' with the dogs. Right now the yard is pea soup, had 3+ in of rain last night & today. The AC unit is a Lennox 3 ton, I'll try to get the plate data for you tomorrow.

  11. #37
    Join Date
    Aug 2012
    Location
    Katy, TX
    Posts
    50
    OKAY, side plate data:
    Model is a Lennox 14ACX-036-230-07
    Installed 11/07
    Factory chg: 8 lbs 9 oz
    Design pressire high side 446 PSIG low side 236 PSIG
    Compressor amps (RLA) 14.1

    Will see what I can do about locating a temp probe tomorrow and getting some temp data.
    claimed to be 13 seer. Tech said he thought it was a 14, which it could be. I have no way of knowing unless the plata model numper is a clue.
    The coil definitely has a TXV on it and it's definitly an A-coil, not a slab.

  12. #38
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,025
    Quote Originally Posted by Cap'n Preshoot View Post
    OKAY, side plate data:
    Model is a Lennox 14ACX-036-230-07
    Installed 11/07
    Factory chg: 8 lbs 9 oz
    Design pressure high side 446 PSIG low side 236 PSIG
    Compressor amps (RLA) 14.1

    Will see what I can do about locating a temp probe tomorrow and getting some temp data.
    Claimed to be 13 seer. Tech said he thought it was a 14, which it could be. I have no way of knowing unless the plate model number is a clue.
    The coil definitely has a TXV on it and it's definitely an A-coil, not a slab.
    Well the Merit Series SEER & EER data I found depends on the match-ups & varies from 14 to 16-SEER & from 11.5 to 13-EER.

    Therefore, we'd have to know the complete match; which is normally always the case.
    Last edited by udarrell; 08-19-2012 at 10:05 PM. Reason: the Merit Series

  13. #39
    Join Date
    Aug 2012
    Location
    Katy, TX
    Posts
    50
    Quote Originally Posted by udarrell View Post
    Well the Merit Series SEER & EER data I found depends on the match-ups & varies from 14 to 16-SEER & from 11.5 to 13-EER.

    Therefore, we'd have to know the complete match; which is normally always the case.
    Apologies for not getting back sooner. Here are the stats & info

    Condenser/Compressor Lennox 14ACX-036
    A Coil: Lennox CH33-44/48B -2 -F
    TXV

    Flwg data retrieved moments ago (12:30 PM Friday 8/24

    Outdoor condenser discharge air temp = 107.5
    Outdoor air temp = 91.7
    air split = 15.8 deg

    Indoor return air temp (at the attic plenum) 73.6
    Indoor supply air temp " " " " 60.6
    air split = 13.0 deg

    Relative humidity: Family rm 57% Master BR 64%
    Room temperature: Family rm 74.7 deg Master BR 70.1 deg
    Dew Point: Family rm 57.9 deg Master BR 58.5 deg
    Master BR is the coldest room in the house, but is the longest run but also has a 12 x 12 ceiling return air grille
    The home feels slightly humid.

    Taylor #9842 digital thermometer
    ExTech #445814 digital psychrometer

    addt'l info: The T-stat is in a hallway with the 20 x 30 main return along with an exterior door and a SE facing window (all morning & afternoon sun, but has a dark shade covering the window). We are able to achieve set-point of 75 deg in the hallway but if the set point is lowered, say to 74, system cannot keep up and the temperature in the hallway actually rises to 77 (as displayed on the T-stat)

    Thanks!!!!
    Last edited by Cap'n Preshoot; 08-24-2012 at 03:17 PM. Reason: addt'l info added

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