Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.
If our community has helped you, please consider making a contribution to support this website. Thanks!

Carrier low ambient control

Options
Paul S_3
Paul S_3 Member Posts: 1,295
edited March 12 in A-C, Heat Pumps & Refrigeration

hey guys. I’m working on a Carrier 7.5 ton split system. It has a motor master low ambient control which modulates both the condenser fans. There are two headers at the condenser. The discharge header which feeds the condenser and the liquid header leaving the condenser. Where should the sensor be located? Carrier tech support is telling me it should not be on the discharge header (maybe he was wrong) that it should be on the liquid header. Problem is when it’s cold out plus the subcooling from the condenser my liquid temp never reaches the “minimum coil condensing temperature (100F)“ that the manual for the motor master states that it maintains. Also if I keep it on the discharge header the fans never slow down enough to keep my header pressure up and suction pressure goes very low. In the picture it doesn’t state discharge or liquid. Also the sensors is made to wrap around a pipe, so I can’t install it into the coil. This equipment is also specifically manufactured for a large corporate account so the generic manuals shipped with the equipment do not have all the accessories that are added. Thanks

image.jpg
ASM Mechanical Company
Located in Staten Island NY
Servicing all 5 boroughs of NYC.
347-692-4777
ASMMECHANICALCORP@GMAIL.COM
ASMHVACNYC.COM
https://heatinghelp.com/find-a-contractor/detail/asm-mechanical-company

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,122

    Don't understand why you're confused. The drawings and the instructions show where to mount the sensor.

    Like the LH drawing shows the third tube from the bottom. It goes on the liquid tube. The sub cooling is at the bottom of the coil.

    Are yous sure your not overcharged causing a low temp liquid line?

    Paul S_3
  • ratio
    ratio Member Posts: 4,227

    You'll find that there are several different sets of installation instructions floating around in the internetz that cover the same model numbers but show different coil configurations and mounting locations. Grab them all and (try to) match the coil drawling to the coil you have. It for sure doesn't go on the discharge header (hot gas side of the coil). ISTR that most of the pics showed it on the line between the liquid header and the subcooler, but there were a few coil configurations that weren't clear.

    At least some of the installation instructions I read called for field-fabbed baffles, too.

    Paul S_3

Categories