Lights blink/dim

Discussion in 'HVAC Heating & Cooling' started by jgalway, Jul 14, 2008.

  1. jgalway

    jgalway New Member

    Jul 14, 2008
    I have a TRANE 5 ton heat pump which causes the lights in the house to dim when it kicks on. Is this a simple service or the heat pump is ready to die?
  2. jimbo

    jimbo Plumber

    Aug 31, 2004
    San Diego, CA
    Probably normal.....a 5 ton unit has a humongous startup LRA, so almost any home would possibly see lights dimming as it starts. ( The LRA is quite likely in excess of 150 amps)

    If it seems way beyond momentary, you could have an electrician check it out.
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  4. geno54

    geno54 New Member

    Jan 4, 2008
    Ask your AC contractor if you have a Hard start kit on your outdoor unit. A factory hard start kit will help your compressor get up to speed faster and reduce but may not totally eliminate the dimming. There may also be conditions in your electrical system that could cause this. A qualified AC and/or electrical company would help determine this.
  5. Marc46

    Marc46 HVAC Contractor

    Jul 27, 2008
    HVAC Contractor
    Central Florida
    Check for any loose "neutrals" in your electrical system.

    Momentary dimming is considered normal,........and as others have said, is due to quite high LRA "Locked Rotor Amperage".
    It should only last a second or less.

    If your unit is not set-up for hard start with a start capacitor, and relay, MAY reduce the dimming by adding a cheap aftermarket hard start kit.
    They simply hook across your run capacitor terminals.
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