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Duct Free Unit

Today I condemned a 2 month new compressor in a Carrier Duct Free heat pump outdoor unit. The system ran out of freon .I've been toying w/ the idea of adding a loss of charge low press safety switch to ALL of my Duct Free/Less systems.Anyone do this? We did not put this system in ,the lawsuits are flying,the fingers are pointing,and the tounges are flapping.I'm glad the fan is way over there!


  • EddieGEddieG Member Posts: 150

    Was this a through the wall unit or a mini split? Any time we do a major repair on the refrigerant circuit, we add a high and low pressure switch. A strap on discharge line thermostat is a simple solution for a low on charge scenario. (opens on temperature rise) I wouldn't recover the charge on a brand new unit to add a switch. They do make the braze in valve ports, that you can add without losing the charge.  
  • TechmanTechman Member Posts: 2,144
    edited March 2011
    Mini split

    This is a wall hung unit. There is a temp sensor on the hi side and it is factory set for 158* F,but that is for hi press/dirty cond coil  situations,not loss of charge protection.And I added a braze schrader tee into the liquid line for faster evacuation and a spot for a hi press safety control.
  • EddieGEddieG Member Posts: 150
    edited March 2011
    That switch is also used

    If a unit is low on charge discharge temperature will increase, if a unit is overcharged discharge temperature will go down.
  •[email protected] Member Posts: 139
    Go for it!

    "Just another reason I am worth what I am!"

    If a unit does not have one, adding wouldn't be that big a deal.

    Why are the tongues wagging? Someone not following thru with warranty? Anyone that has worked with mechanical things know that anything, at anytime can and will fail for whatever reason! Just because it is new, does not mean it cannot fail. Just less likely.

    Don in MO
  • TechmanTechman Member Posts: 2,144
    Duct Free

    Hi Don, this one little unit is part of  a $12,000,000 building  renovation,there are hydronic heating problems,other HVAC units problems,exhaust fan problems,and the radiant heated office is cold,and,and!So ,some people are upset .What a mess!The ray of sunshine is I get to be involved in troubleshooting/repairing/advising and reading more manuals on the proper operation of the control system and stuff.   


    Eddie,good point ,but how long does it take to heat up the discharge line to cutout the compressor. This past winter was cold and very snowy I'm thinking that the weather covered over a leaking problem
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