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no sight glass/moisture indicator

what is the reason why so many mfg's of R410a  units tell to not to install sight glass/ moisture indicators on their systems?with POE/PVE oil and r410a so much more sensitive to moisture ,why not? I really don't want to hear " moisture is not supposed to be in the system in the 1st place and if the mechanic did the job properly you don't need them ".that logic is true for every oil and refrigerant , so, why were the indicators invented in the 1st place. this Q is for split units and/or ductless units as well . thanks.


  • Tom Blackwell_2
    Tom Blackwell_2 Member Posts: 126

    I believe the reason is that they are afraid of the liability if a sight glass not rated for 500# was used and ruptured.
  • don_9
    don_9 Member Posts: 395
    edited March 2010

    I believe its to keep people from trying to clear the site glass.too many over charge unit form guys trying to clear the site glass.And we all know what kind of issue you have with a overcharge unit.

    In short, they're not trying to make it dummy proof.
  • HVAC_Journeyman
    HVAC_Journeyman Member Posts: 8
    Site Glass

    Well anyone that charges a system using a site glass should be severely beaten.

    I think a site glass is a very good component to install on a system, new or old. It gives you the ability to monitor the condition of the system's refrigerant. Just make sure the glass is rated ( most are these days) for the higher pressures of 410A. I like to place mine directly after the liquid line drier ( another component I believe belongs on every system). 
  • HVAC_Journeyman
    HVAC_Journeyman Member Posts: 8

    I thought about my last post. There are a few times where a site glass is used for charging, such as the head start receivers on a Liebert. So I need to be beaten...lol 
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