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  1. #1
    Join Date
    Jan 2019
    Post Likes

    Coldroom Misa MEP13

    Hi Guys,

    Im new to the forum, and my first post is a request for some advice ... 3 months ago i've installed a positive coldroom 0c/5c for a customer, got called by the customer 2 days ago, telling me that the temperature wouldn't go below 10c during the day, but at night it drops to setpoint i.e 2c... (The system came with a r452a compressor and a r404/507 danfoss expansion valve but wasn't precharged, so after vacuum we've charged the system with r404a.)

    Checked the refrigerant pressures which were as follows:

    Low side = 2.5 bar / 20 psi
    High side = 250 to 275 psi
    Coldroom temp = 10c
    Ambient temp (around condensor) = 35c to 38c

    I've did some tests with the system by switching off the evaporator fan for 15 minutes and the evaporator coil dropped down to -23c, switched back on and the coldroom temperature raised to 9c and evaporator to 4c and it remained at these temps for nearly two hours, until night where it reached setpoint.

    Bearing in mind that i've installed the system during the end of winter where the ambient temp was around 22c to 26c (when it was working fine), i am wondering if its the hot summer days that might be affecting the system and if maybe the refrigerant charge might need to be readjusted??? but i don't really know to what pressure, should i add more refrigerant?.. Please let me know what you think guys.... THANKS

  2. #2
    Join Date
    Aug 2002
    Southold, NY
    Post Likes
    Is there a Sight Glass then charge to a clear glass.

    If theirs a Head Master Control for low temp operation follow sporlan 90-30-1

    Whats the SH at the evap and at the pump? (in °F please)

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