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  • fixbear

    Member
    March 1, 2017 at 1:41 pm

    They are a real piece of engineering, but they are prone to leaks due to the tube bundle expanding and contracting. One has to make sure to use their leak detector on the water vent. 

  • olivero

    Member
    March 1, 2017 at 8:39 pm

    Thanks for that Fixbear.

     

    Would have never thought of that.

     

    which part would put the compressor in overload? My idea was to run 2 seperate lines, 1 for cooling, 1 for freezing which is not the case in this moment.

     

    I was just looking at the document you sent me and regarding the suction accumulator and it says it prevents frost and sweat.

     

    The suction service valve on the compressor as well as a good 1/4″ of the compressor builds up frost when the unit is freezing and definetley sweats when its cooling, how can that be if the accumulator prevents that? I have confirmed I have SH so I am not worried about flooding the comp but just curious if there are exceptions.

  • fixbear

    Member
    March 2, 2017 at 5:29 am

    “which part would put the compressor in overload? My idea was to run 2 seperate lines, 1 for cooling, 1 for freezing which is not the case in this moment”.

     

    Your compressor has a very big bore for it’s size and is designed only for low temp. That means suction pressure has to be kept below about 30 psi.  As the pressure rises,  so does the load.  If you use a ammeter on the compressor,  as you adjust the expansion valve or as the load comes down you will see a load change. Other than the starting inrush it should never be over RLA rating.  Remember that start inrush is normally 17 times full load amps. 

     

    Air research makes most of the accumulators and recievers we see. A suction accumulator is primarily used to prevent liquid flood back slug.  As you can see the inlet is below the outlet and faces down. The inlet is at the top and the “U” pipe has a metering hole in the bottom to return oil.  It is a must have if line sets run through a cold area or the evaporator is above the compressor with longer runs.  They also have versions with a tap off for oil tank and make up pump.

     

    I was just looking at the document you sent me and regarding the suction accumulator and it says it prevents frost and sweat.

       It does, if there is some liquid causing it. Your system is at a below zero suction.  Naturally the gas is cold and will carry away heat even though it is light. It still has mass.   Copeland puts the suction on the end of the motor on this unit just to help with that .  The gas has to pass threw the motor,  into the crankcase, and then up into the cylinder.  Frost is expected over the motor area.  One needs to worry if it gets to the crankcase. 

  • badbozo2315

    Member
    March 2, 2017 at 4:12 pm

    I have to say, Mr Bear, while this whole thread has been very informative to this Hot Side guy, your last paragraphs above contain a wealth of information and knowledge right there. Thanks.

  • olivero

    Member
    March 2, 2017 at 9:08 pm

    Thanks Bear.

     

    That makes more sense then, I was thinking with the accumulator there should be no frost so I was worried for a second.

     

    I still think there should be a more effecient way of running it, for the purpose of learning something, why do you think having 2 seperate lines going down is a bad idea? The suction pressure would stay well below 30 in both cases, just SH would be different depending on the application of cooling or freezing.

  • fixbear

    Member
    March 3, 2017 at 7:52 am

    Running two lines would just be a extra. Unless you had a second evaporator.  And even then they could just Tee with solenoid valves.  Trenton is already controlling the temp of the box somehow or they wouldn’t have 3 modes.  One way is to have different evaporator pressure regulators on the tail coil with valves (Dual Pressure valve). Lets the compressor go very low in it’s pressure curve but holds the evaporator at a set temperature and pressure (load). That way the compressor load will self regulate.  With the advent of AC variable speed motor control there are a lot of people trying to use motor modulation.  Primarily on air conditioning right now.  There is also a lot of new electronic TXV’s coming out. But modulating there creates a lot of superheat control and compressor load problems.  One still wants a saturated evaporator for the right capacity.   

     

       I’m certain that someone spent a lot of time designing this chiller.  It  had to be a major pain if the manufacturer and Trenton worked hand and hand on it to the point that Trenton made a service manual special for it.  Perhaps Trenton also made the evaporator?   

  • olivero

    Member
    March 3, 2017 at 8:44 am

    That’s a good point there.

     

    I wouldn’t be too surprised if Trenton made the whole refrigeration enchilada. Seems like Delfield barely has a clue on this unit when it comes to the cold side but they can help you on the electrical side.

     

    They say it’s made in Italy, so it might even be 3 different companies making it. What is that service manual of which you speak? I got the condenser maintenance manual and the blast chillers service manual, is there something else I am missing?

  • fixbear

    Member
    March 3, 2017 at 11:33 am

    Trenton installation and maintenance manual for the T-40 condenser.  Trenton #1068156  

  • john

    Member
    March 3, 2017 at 11:54 am

     fixbear, talking about this?
    http://docs.t-rp.com/1068156.pdf 

  • fixbear

    Member
    March 3, 2017 at 5:08 pm

    The number corresponds, but it’s generic to their condensers. The manual section for look up said for the T40 specifically. under his condenser model.Really would like to talk to the engineer that designed it.

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