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  1. https://www.hvac-talk.com/vbb/showthread.php?13670...

    https://www.hvac-talk.com/vbb/showthread.php?1367061-YVAA-high-eductor-temps/page2

    re same.
  2. Point is to keep the oil temp above saturation at...

    Point is to keep the oil temp above saturation at any temperature.

    40-80 watts is not expensive insurance.

    Only times I've see issues is when compressor blankets or sound enclosure are uses...
  3. Both are hp discharge gas, should not make a...

    Both are hp discharge gas, should not make a difference. Changes usually made to simplify or cost reductions.
  4. Don't like starting a compressor with solvent in...

    Don't like starting a compressor with solvent in my lubricant.
  5. Always added them on on compressor change outs...

    Always added them on on compressor change outs and new equipment. Cheap insurance.
  6. no sump heater? non bleed port txv? drain pan...

    no sump heater? non bleed port txv? drain pan trap?
    Interesting condenser header/subcooler arrangement.
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    Maybe some do modify the oil, but I'm not aware...

    Maybe some do modify the oil, but I'm not aware of any chiller manufacturers doing it. I've worked for factory services of 5 different companies none of which did anything other than relabel. None...
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    That narrows it down to a screw or recip. ...

    That narrows it down to a screw or recip. Capacity stages or minimum unloading?
  9. Replies
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    656

    Bitzer screw, scroll or recip? POE or mineral...

    Bitzer screw, scroll or recip?

    POE or mineral oil?

    Test % poe with refractometer?
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    They suck for low flow control. I used to cut a...

    They suck for low flow control. I used to cut a bushing to limit the valve to ~10% to stabilize on startup.
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    Use the mfg recommended oil under warranty. I...

    Use the mfg recommended oil under warranty. I would not mix even recommended oils due to potential differences in additives, change oil makers and change the full charge to be safe.
    Typically...
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    " The control loop basically hunts between about...

    " The control loop basically hunts between about 0% to 20% on start up. I felt one factor might of been the actuator stroke time since it never seemed to do this originally."

    Valve may need to...
  13. Replies
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    PID is more important than speed. Condenser...

    PID is more important than speed. Condenser water temperature rate of change should be limited to < 1*f per minute. Screw chillers are the most critical for oil management.

    Check the valve for...
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    HF may have .5 - 1.5 pressure drop. Need the...

    HF may have .5 - 1.5 pressure drop. Need the ahu/coil specs & existing total external pressure drop for evaluation.
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    To prove performance the same information is...

    To prove performance the same information is needed regardless of who is taking it.
  16. Replies
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    PM me and I will send you a list of about 30...

    PM me and I will send you a list of about 30 causes of oil loss/low oil pressure.
  17. Replies
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    656

    Not nearly enough info. Would need log sheet,...

    Not nearly enough info.
    Would need log sheet, model numbers, piping iso, cycle rates, etc......
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    Yes, blade height in the venturi can change air...

    Yes, blade height in the venturi can change air flow and amp draw
  19. Replies
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    Most chiller mfg make equip that would work. ...

    Most chiller mfg make equip that would work.
    Issue ive seen a couple of times is the evaporator should be 316 ss, not 304 ss due to potential chlorides. If temperature set point is critical look...
  20. Oil heater burnt out, may not have seen oil level...

    Oil heater burnt out, may not have seen oil level after starting with saturated oil
    Split unit factory recommends adding oil on start, may have calculated wrong
    Original compressors so not due to...
  21. Extreme oil overcharge. Liquid flooding...

    Extreme oil overcharge.
    Liquid flooding compressor causing swings in pressure. Microchannel ports restricted by by liquid oil entering causing high pressure and high pressure drop.

    evidence:...
  22. Removed coil panels, put gauge and temp probe on...

    Removed coil panels, put gauge and temp probe on compressor discharge.

    compressor discharge ~ 100# higher than liquid line, swinging > 50#, pegged gauges a couple of times, discharge sh 2-4*f...
  23. Step #2 did test for non-condensables, ...

    Step #2

    did test for non-condensables, saturated and ambient < 2*f difference, liquid line pressure still swinging

    Step #3?
  24. about 70*f ambient, 2 of 3 fans steady operation

    about 70*f ambient, 2 of 3 fans steady operation
  25. Cooling production area where they are making...

    Cooling production area where they are making covid mask. Coils only moderately dirty.
  26. Correct on first step. Recovered refrigerant to...

    Correct on first step.
    Recovered refrigerant to ~ 15*f subcooling. SSH unchanged, Liquid line pressure still swinging ~ 50#.

    Step #2?
  27. Head scratcher, Trane RTUJC504c, 50tn condenser

    At an industrial site today assisting a tech doing pm's. Seen similar problems, but this is the first with this combo.

    Scroll compressors, two per circuit, microchannel condenser, tube/fin...
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    I'm sure they will plan on only using one at a...

    I'm sure they will plan on only using one at a time, besides it helps hp operation in the winter. Is that approved flashing at the foundation? All the insulation and a builder's grade unit sounds...
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    Coil iced over long before 20 psi ... not a lp...

    Coil iced over long before 20 psi ... not a lp but now a freeze switch

    Either way far better than not.
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    Hp must go on the compressor discharge...

    Hp must go on the compressor discharge (preferred) or liquid line. Lp is usually installed on the liquid line as a loss of charge switch, if on suction will require a time delay.
  31. Replies
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    Not exact, but compare return, space & attic/craw...

    Not exact, but compare return, space & attic/craw temps. Higher differentials the better.
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    Load is based on btu's. CFM takes into account...

    Load is based on btu's. CFM takes into account selected equipment sensible/latent capacities.
  33. Saturated temp and pressure are condenser. 41.9...

    Saturated temp and pressure are condenser.
    41.9 & 44.4 are evap

    If R-123 evap should be in vac with sat <40
  34. Looks like to me you have the condenser and...

    Looks like to me you have the condenser and evaporator mixed up.
  35. "Everyone will say you are liable if you fix or...

    "Everyone will say you are liable if you fix or change things. But you are also liable if you don't. Please, we are all smarter than that!"

    Voids listings. Would not change without a letter from...
  36. send me an email address for ref document

    send me an email address for ref document
  37. Assuming the chiller evaporator load is not...

    Assuming the chiller evaporator load is not changing, the condenser DT will be proportional to the flow rate causing an increase in discharge pressure and reductions in capacity & efficiency. Very...
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    Based on my experience thermistors work great in...

    Based on my experience thermistors work great in wells, thermocouples work better on surface temperatures since they are more easily secured and insulated.

    Test: put a thermistor in a cup of water...
  39. Recip should have a heater, scrolls may not. ...

    Recip should have a heater, scrolls may not. Copeland requirement based on ref charge. Heater is always a good option.

    In winter I used to start and run the hp units in heat so strips would be...
  40. Trace the wiring from the back. Might go to your...

    Trace the wiring from the back.
    Might go to your neighbors.
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    Only if you have the compressor vendor...

    Only if you have the compressor vendor performance data and operating within design envelop.
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    "International Mechanical Code (IMC) 1101.10...

    "International Mechanical Code (IMC) 1101.10 Locking access port caps. Refrigerant circuit access ports located outdoors shall be fitted with locking type tamper-resistant caps or shall be otherwise...
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    Sounds like an "I told you so" question. With...

    Sounds like an "I told you so" question.

    With some variations, assuming correct operation:
    1. 30-45 minutes once on site, tools in hand
    2. 5-15 minutes to stabilize if near design conditions,...
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    "Residential, multifamily, and townhouse...

    "Residential, multifamily, and townhouse developments may be subject to significant fines stemming from the lack of enforcement of the 2009 changes to the International Residential Code (IRC) M1411.6...
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    sent

    sent
  46. Replies
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    Yes. Email?

    Yes. Email?
  47. Replies
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    Figure 2 in manual has a table showing position...

    Figure 2 in manual has a table showing position reference, output voltage, and gap.
  48. Replies
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    Vane position is used with speed control and...

    Vane position is used with speed control and surge mapping. Could affect loading.
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    Depends. Model number?

    Depends.

    Model number?
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    North pole end to white dot. Make sure snap...

    North pole end to white dot.

    Make sure snap rings on vanes are fully seated, Cheap metal.

    Send email address...
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