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  1. #1

    Oil Heaters On York YKNCNC

    I have a bad thermostat on a oil heater on a YKNC at a textile mill. I have ordered a new one that will be delivered tomorrow morning. My questions is why would this chiller have 2 oil heaters? Both heaters are 1500 watts, but one is 115V and the other is 575V. There is no wiring diagram on the unit. Just curious if anyone else has seen this before?

    Thanks to all and glad to be a part of this site.

  2. #2
    Join Date
    Aug 2000
    Location
    Austell, Ga.
    Posts
    1,296
    Yes..That was common practice on the early YK's to have dual oil heaters. The thermostats are located in the heater cover, The thermostat for the 3ph. heater controls a relay in a box besides the oil pump starter. The 115 volt heater uses the 20 amp lower fuse in the control panel. York was very serious about keeping the oil temp. up on the early YK's.
    Ain't "None" of us as smart as "All" of us..

  3. #3
    Thanks Richard. Why does the thermostat in the 575V heater control the relay? I notice the contact of the relay is fed from the auxiliary contacts of the oil pump. Again not having a wiring diagram I am just curious as to why one heater is controlled off of its internal t-stat and the other is put in play by the oil pump starter? Also why 575V and 115V heater. Seems strange.

    Your help and input is greatly appreciated.

    Mike

  4. #4
    Join Date
    Aug 2000
    Location
    Austell, Ga.
    Posts
    1,296
    I cannot even attempt a guess on what the engineers thinking was at the time installing two huge heaters on the early YK's. The new ones uses the "Micro-Processor" to heat the oil only 50-55Ίf above the "Saturation" temp.In some cases the oil might be just 100Ίf before the panel allows a start.. Seems to work quite well and the heaters do not cremate the oil during the off cycle by trying to maintain the 140-145Ίf we are all so used to. What will REALLY shake one up is when you find ICE on the top of a new YK oil sump while the chiller is running..Scared the hell out of me when I saw it on my first one.
    Ain't "None" of us as smart as "All" of us..

  5. #5
    LOL. Thanks again Richard for your input, it is greatly appreciated. Hope you have a great day tomorrow.

    Mike

  6. #6
    Join Date
    Jun 2008
    Location
    Windsor, Ont.
    Posts
    503
    Quote Originally Posted by ibabamafan View Post
    Thanks Richard. Why does the thermostat in the 575V heater control the relay? I notice the contact of the relay is fed from the auxiliary contacts of the oil pump. Again not having a wiring diagram I am just curious as to why one heater is controlled off of its internal t-stat and the other is put in play by the oil pump starter? Also why 575V and 115V heater. Seems strange.

    Your help and input is greatly appreciated.

    Mike
    The 575V heater relay coil is energized through a series circuit consisting of the thermostat and a normally closed set of auxillary contacts on the oil pump starter thus preventing heater operation while the chiller is running. I believe they use the thermostat contacts for pilot duty only as they are not rated for 575V.

  7. #7
    Again your response is appreciated. You are a classy gentleman. I hope somehow I can help someone or you in the future. I have been doing this for 36 years. How long have you been in the industry? You have a great knowledge.

    Take care,

    Mike

  8. #8
    Join Date
    Aug 2000
    Location
    Austell, Ga.
    Posts
    1,296
    I was born into this trade...My father taught the first A/C Refigeration trade school in Georgia(Industrial Trades Institute) in the mid 40's. When I worked for him I got food and lodging at the age of 12. He always said I was overpaid then. I was job foreman at the age of 15 building the first refrigerated ham plant in Georgia(Talmadge Farms, Lovejoy) installing 350 tons of refrigeration with the largest units(Brunner) being a Full 5 tons capacity. For years I travelled taking care of the American Embassies and whatever the Charge-de-Affairs pushed upon me from Tuna boats(Panama) to getting water to the Guatemalens after a severe earthquake. From Moscow to Madras and Legos to Recife...Been there...done that..
    I am now 71 and have retired twice..(The Brett Favre of HVAC)
    Working(Ha) now at a data center whilst retired
    Damn.....Reads like a resume.....
    Ain't "None" of us as smart as "All" of us..

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