Problem with HWW036 - Puttering out ???

Discussion in 'Maintenance and Troubleshooting' started by DavidCraig, Jan 2, 2014.

  1. DavidCraig

    DavidCraig Member

    New 3 ton Heat Controller, commissioned October 2013

    [ Edited ]

    What would you recommend for getting accurate temp readings for source and load EWT/LWT? Every thermometer and/or instrument I've used gives different readings?

    How do you calculate calculate head moved and total heat? This is an example of what I've been using:

    9.0 GPM * delta 8°F * 8.34 lbs/gal * 60 minutes = 36,039 bthu
     
    Last edited: Feb 12, 2014
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Heat Controller has pressure drop tables in the I/O manual to help figure GPM. Head is a function of the resistance of the machine and the loop field.

    Now what is the system doing or not doing?

    Mark
     
  3. DavidCraig

    DavidCraig Member

    Thanks. I've not been able to locate that table ... must be googling incorrectly. Have the design-guide, which is full of error - just look at page 9 and try to make sense of the numbers for Source EWT 40°F !!!

    Can you provide a link to that specific I/O manual?

    The problem seems to be dropping delta T on the ground loop. One would expect this as EWT drops. It was 40°F and is now 41°F ... going up in January as use has gone up? Probably not measuring the temperatures correctly. I've used 3 different ways and all disagree. [ Hence the question, how do you folk measure this accurately? ]

    Another oddity is that, based on 12 years of heating with oil, 110°F water temp for the radiant floor did not deliver 30,500 btu - 110° would have been insufficient to heat the home during colder weather.

    So what is needed is to exactly measure operating parameters and calculate performance ... to verify that it is healthy or reveal any problems. The unit specifications closest to current operating conditions are:

    Source @ 40°F EWT and Load EWT @ 100°F (both @ 9 GPM):

    Source LWT not specified in table* Pressure drop is 6.5 psi
    Load LWT 106.8° Pressure drop is 2.1 psi
    Power consumption 2.39 kw
    HE Mbtuh 22.4
    HC Mbtuh 30.5

    *I calculate design LWT to be 35°F based on this method: 22,400 btu / (9 gpm * 8.34 lbs/gal * 60 minutes) = delta T of 4.97°F



    Here is what I have so far:

    For flow readings, am using a mid-western differential gauge 120AC-00 10psi 4 1/2" dial.

    Source pressure drop is 6.2 psi. So flow ~8.8 gpm --- the pressure drop table you mentioned would be really handy here.
    Load pressure drop is 2.1 psi. So flow is 9 gpm

    These reading match calculated values based on ground loop length * dia, pump specs, coil pressure drop, etc. [ Two 'witnesses' agree ]


    Power consumption is 2.7 kw

    This is based on a Submeter: 20 hours continuous operation using ~60kwh. So 3 kwatts minus 280 watts for circulators (UPS26-99FC and UPS15-58FC)
    I need a good ammeter as a second 'witness'. However, the compressor motor is just warm, not hot. So it certainly isn't sucking gobs of power.

    This is a little higher than 2.39. But the Load EWT is ~103°. [ The radiant floor temp = 108 to 112 as unit cycles with a 100 gallon buffer tank ]


    So now I need the temperatures. It seems that source EWT is 40° and load EWT is 103°. Plus or minus a couple degrees on this doesn't matter a lot. But the delta T's need to be good to 0.1°F ... otherwise the calculation goes all over the place. I've measured source delta T <3° and the load delta T >10° - these are so far off it doesn't make sense. The latter could indicate some sort of flow restriction - this would increase power consumption as is seen above and this higher delta T reading has been somewhat consistant.

    Does anyone have suggestions on getting precise delta T readings?




    On the positive, the home is being heated fine considering the ice-box weather recently. It is a 2000 sq ft home outside Saratoga Springs, NY (a cold winter location) - pleanty for a 3 ton.

    Thank you for your patience in reading this post
     
  4. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    David:

    Get me model #s and I will look for a link.

    Mark
     
  5. DavidCraig

    DavidCraig Member

    Model # HWW036A1C10CFC BTW, do have the I/O manual - it just gives minimal flow/pressure lost values


    As of an hour ago, the pump has stopped working - Lockout

    Put into test mode and it reports Fault #4 - Low Temp Cut-Out Coax. However, EWT is 38° F and JW3 is cut so this fault should not occur unless temp goes down to 15° F

    Most notable is that the compressor makes a puttering, almost clanking sound. The motor never gets hot (when it was working) and draws about 15amp. But the refrigeration pipe coming out gets very got - there is even a slight burning rubber/oil smell.

    As far as I can tell, this code is in error - something else is causing this fault. Either it doesn't abide by this jumper (and is set for 35° ) or something else is causing this. When speaking to a technician last fall, I was told that this sensor is not on the water but on the refrigeration line.

    Any ideas?

    While compressors often make puttering sounds, any reason for this to get loud and 'clanky'? If it is just a jumper/sensor problem, is this sound relevant?
     
  6. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    maybe loop circulation pump has failed? which would cause low temp lockout on the heat pump. you need to verify water temps or water flow
     
  7. DavidCraig

    DavidCraig Member

    EWT is 38° F and pressure drop is 6 psi (about 8.5 GPM)

    Confirmed temp sensor is on refrigerant line, not water line

    Could low coolant cause this? I've had air-conditioners start to freeze up when some of the freon has leaked out ... but don't remember the compressor sounding different.


    I've been told that if a compressor is 'starved' it will make the sound I describe. Unless flow was blocked or EWT very low, what other reasons could there for a compressor to 'starve'?
     
    Last edited: Feb 10, 2014
  8. DavidCraig

    DavidCraig Member

    Well, a couple hours later ...

    Held thumb on sensor to slightly warm it. Now system is running.

    For what it is worth, the problem only occurs when starting up and load water is < 90° F


    Talked to a couple guys local. One claims to have invented standing column systems and says it is the only system that works ... ground loops don't work and are built because of greed ... he will not look at my system because it has methenal antifreeze which is the most dangerous chemical on the planet ... etc -- needless to say, with what he said, I don't want him near my system, lol

    Another fellow, a real nice HVAC guy, thinks it is a sensor issue and that the 'clanks' during startup are not so unusal (something to do with oil that settled) ... and could be more so because the load temp is low.

    Well, any suggestions?

    I'll call the manufacture tomarrow ... they closed a few minutes after my problem - Murphey's Law.
     
    Last edited: Feb 10, 2014
  9. DavidCraig

    DavidCraig Member

    Spoke with tech support. Ordered a FieldPiece dual temp meter ... hopefully get it today. Currently have single multimeter temp probe that seems to read a couple degrees low.

    As per suggestion, measured the temp on the expansion valve where the units own temp sensor is located. With EWT of 38°, it read 14°F. That seems quite low.

    Question: For EWT ~40° F, what would one expect the refrigerant temp to be, right after the expansion valve?

    On this unit there is about 5" from this point to actual coax connection. One would expect this to be lower that the incoming water, just as the compressor discharge is 'superheated'.
     
  10. DavidCraig

    DavidCraig Member

    Well, FINALLY the problem is confirmed. After endlessly being dismissed by tech support that it is a water flow problem (sound familiar?)

    The suction line is only 35psi instead of 100psi. The sound and occasional 'clanking' is from this. So is low source delta T. Discharge is 250psi instead of 300psi. Moving the bulb off the suction line and into hot water then cold water changes this, but no better than 60psi.

    Am told this is a bad expansion valve. Could it be low refrigerant instead? Why would this valve fail in this way?


    The delta T shifts with this problem, which would make sense with a valve issue. At times it would measure 3°F and other time 4.5° (it should be just over 5° with water flow). Because of this 'shifting' it has been impossible to nail down HE - thus have been pulling hair out. Tech support kept insisting that I nail delta T down. Finally, measured temperature where their sensor is just downflow the expansion valve and got 4°F within 15 seconds of starting - then they said to get the pressures read.

    On the good news side, the Fieldpiece DT4 takes the guesswork out of delta T. You still have to fuss with calibration of actual temp but its easy to zero in on a known or at least for the delta.

    Has anyone else had problems getting delta T 'shifts'?

    Have noticed various posts of delta T gradually lowering over the years. With open systems, people descale yet it doesn't change. Is it possible a delta T change would be refrigerant or expansion valve issues? The manufacture wants all the blame to be system design, maintenance, or setup. But it isn't always these.

    One more question, do I need to be concerned that the compressor has been damaged because of this problem? The sound began about 7 weeks ago.
     
    Last edited: Feb 14, 2014
  11. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Bad TXV's go in spurts. Compressor damage; could make a case that it was working less hard. Lots of different measuring tools, we still mainly use a thermometer.
    DT lowering over the years? I saw a recent comment about DT lowering over the years but still await GPM to verify that change in flow is not the reason for DT change. With clean heat ex, there should be no change in DT.
     
  12. DavidCraig

    DavidCraig Member

    Thanks. I've had glass thermometers attached to the lines from day one. A problem (besides being sluggish) is that the readings were different than everything else I've tried - BK multimeter with temp probe, dial indicators (yes they are course but when 7 out of 8 agree it makes one a believer, lol), etc. Presuming the FieldPiece is working, it agrees with thermometers - which surprised me given the readings. Even if not callibrated quite right, it is easy to get the delta good. At any rate, when the HWW has not been on for a few hours, and the source pump has been running to mix temps up a bit, EWT is 5° less than fresh water being pumpted out of a 200' well. In this area, the water should be about 50° F and thus EWT 45°.

    When HWW has been working 90+% of the time for weeks, the thermometers indicated EWT 40-41°. This number seemed too good to believe. And since heat being produced has been gradually reducing, I thought is was from ground loop slowly cooling as one would expect. Afterall would anyone here expect a 500' vertical loop on a 3-ton system to be this good after a couple months of very cold weather? A WF bid I received showed EWT getting down to 30° with a 40,000 BTU HWW.

    At any rate, currently HE is 16,600 btu whereas the specs show it should be 22,400 btu - about 2/3 what it should be. Since performance has gradually reduced, pump 'puttering' gradually increased, and startup failures increased - all this seems to me like a tiny leak. But perhaps the TXV is gradually failing. Perhaps the compressor is gradually failing.

    In talking to the manufaturer, none of the proper test proceedures have been followed by the repair guys. So when the new part comes in, am going to have them removed the R410a and weigh it - then we will know if there was a leak. While never achieving proper suction, moving the TXV bulb into hot water and/or cold water does change it - so the bulb is partly working.

    Can't express the frustration of this all. A few years back, an 'expert' ruined my central air. Now what next... Thus I ask and learn.

    On the good side, in spite of the heatpump working well below specs, I've used 4000 kwh (as of yesterday) heating since October. In NY that cost about $650. Oil would have cost over $2000 by now. Imagine how next year might be when the unit performs according to specs.

    Again, any help would be appreciated - especially about proper refigeration.
     
  13. DavidCraig

    DavidCraig Member

    TXV replace and now working near specs.

    One problem remains however. The suction pressure is a little low, 80 instead of 100. In order to get the best pressure and the best HE is to reduce the load flow to 7 GPM instead of 9 GPM. Any ideas?
     
  14.  
  15. DavidCraig

    DavidCraig Member

    The replacement TXV valve now needs to be replaced. Its been two weeks and gradually the HE has been dropping and other symptoms showing up.

    Any ideas?
     
  16. Geo can be tricky.

    If you are not hvac, here are some things I believe: The failure rate of thermostatic expansion valves is very low to begin with. They can be man handled, however. Read on. Remember that the function of the txv is to meter the perfect amount of refrigerant into the expansion coil or heat exchanger for maximum efficiency. If they stick wide open, we can flood the coil. If they fail at 10%, we have no ability to do work. While the heat pump is running, this device automatically keeps the evaporator 92% + full so we can get maximum work out of that coil or heat exchanger. (That is one reason why txv units cost more. Their benefit: They automatically adjust)

    One of the better ways to initially test them is to unstrap the gas bulb from the suction line while the unit is running and alternately dip the thick end bulb into icewater watching running suction and head pressures and then either holding the end bulb in your hand or dipping it into 80 degree water or something like that. An hvac tech would compare the pressures: suction and head, and decide whether the valve is responding properly or not. Refusal to respond means the txv is not able to change position, therefore it is bad. If it passes that test, then we don't have to replace it.

    Factory built systems stay clean until compressor burnout or something else weird happens. Pros keep systems clean.

    If you have a bad expansion valve, recover, put in as many new parts as possible including things like schraeder valves, replacement factory driers and so on. It is cheaper to replace a reversing valve 24 volt coil at the 5 or 10 year mark with a new coil than have an OLD one short and overheat, killing the entire reversing valve. (That's just my thought) Cleanliness, cleanliness, cleanliness is next to Godliness.

    Pros recover refrigerant, and take systems apart fast, and keep moisture out of lines by purging with trace nitrogen, and braze things back together with 15% silver solder or better, FAST, using soaking wet rags or quality heat dam "paste" because excess heat will destroy delicate txv's, reversing valves and so on. I use acetylene. Get it hot fast, get in, get out and cool it off. We usually already have the vacuum pump hooked up to the fittings and sometimes only have the system "open" for only 2 - 3 minutes depending on what is being replaced. Unfortunately here on compact close coupled systems, they can be hard to work on properly unless they are removed taken apart and set on a bench. Some of us work like clumsy trolls, others are highly skilled elves.

    (I just had an inexperienced older guy at work, who should have known better, fry a brand new refrigerant valve by trying to braze it in place with map gas which didn't produce enough heat quickly. 6 minutes later he had a very hot valve that wasn't soldered but well fried) .

    Leaks can drive you crazy but you have to find them. Refrigerant leaks usually go from within the system transferring to water because of the higher pressure, especially with R-410A. Does the coil have an emergency relief ? Is it the high or low pressure switch ? Could it be from the compressor terminals ? reversing valve ? evaporator coil, water coil #1, water coil #2 ? Water rarely enters the refrigerant side openly unless you have corrosion damage or perhaps a full seam failure, with the water entering the refrigerant side as the refrigerant pressures drop below 100 psig and approaches water pressures. Once water enters the refrigerant side, that compressor is going to ground or short out and water meeting the POE oil will create a MESS.

    I will leave discussion of closed loop water leak issues to the hole diggers and loop buriers because they work with it everyday. The more connections, the more potential for leaks.
     
    Palace GeoThermal and urthbuoy like this.
  17. DavidCraig

    DavidCraig Member

    This is a new system, that is, it sat for 12 months then was commissioned in Oct. Efficiency gradually declined and finally would shutdown when starting because it thought that EWT was to cold.

    The main problem was the TXV. However, when emptying the system there was 8 oz short on refrigerant. Leak testing was inconclusive - to loose just 1/2 lb of refrigerant in 16 months is, perhaps, a tiny leak ... time will tell on this one.

    The TXV and filter was replaced in fashion you describe. All back together and then HE matched specs. However as the days have gone by, HE as gone down although the source and load temps (and flows) remain the same. Upon repair HE was 24,400. Now HE is 20,000. Compressor is beginning to make its distinct 'puttering' sound with startup. It is just a matter of time (weeks?) until it reaches shutdown.

    While it is possible for the new TXV to be bad ... again. It makes one wonder if something is causing TXV failures. The guy who did the fix took off the top diaphragm of the old TXV and noted if was full of oil, which he had never seen happen before. Could there be the wrong kind of or quantity of oil in the system? I am told that there is oil as well as refrigerant in the system - for the sake of the compressor.

    Aside from the part being defective or damaged, is there something in the system that could cause gradual failure of this component?
     
  18. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    David:

    It has been an interesting time for us since my wife traumatic brain injury, so I have not done my due diligence here in helping with tech issues.

    Let me share a few un-researched things I know.

    I have a five ton W2W and its twin on a job. They are CM and one is fine and the other has lock outs that make me suspect the TXV. I can never catch it misbehaving while I am watching it. So, since I live an hour each way from the machines it takes some planning just to get to the job site. The problem unit does not putter, but violently trips the unload-er in the scroll compressor. I rest the unit and it works fine until I get home.

    The other unit runs like a Swiss watch.

    I will be looking at the bad machine this week and report what I find.

    I saw someplace there may have been an issue with coatings of some heat ex-changers, it a coating is coming off the inside it will move with the oil and refrigerant and could cause blockages. Some blockages can be permanent and others intermittent, the latter being the worst to find and resolve.

    As I re-read this thread from the top I found you maybe solving your own issues. Yes a TXV can starve a compressor of oil and the cooling from vapor refrigerant. The oil found in the first TXV replaced could mean "something" is clogging the new TXV and depending on the filter/dryer core could be getting past the filter part. That possibility may be causing the slow degrading of your machine.

    I like to use ceramic core filter/driers. Even if a manufacturer sends me a free OEM replacement I ask if I can use what I like better.

    Joe is correct, TXVs can make you crazy. Go three years without find one bad to three weeks of one each week.

    Mark
     
    Last edited: May 28, 2014
  19. ==================================

    HE ?? I'm sorry. No comprende. Please remember these blogs are being looked at and read AROUND THE WORLD. // 8 OZ loss is beginning to be a problem, yes.

    Loss of heat output can be related to refrigerant loss, or water or fluid flow, or even air flow. I repeat: Thermostatic Expansion Valve failures are around 0.5% even in China or Bornio !

    It is possible to get a bad one out of a batch of hundreds, but Sporlan and the other companies don't make money by selling defective ones. I have identified 3 gone bad in my 20 + year career. Your hvac technician needs to "observe carefully". EXV's rarely just fail. I have never seen oil in a txv. However since the equalization line comes off the suction line, (which by the way should be on the TOP SIDE)

    Understand that equalization lines should always come off of the TOP of the suction line TO PREVENT OIL FROM ENTERING AND CLOGGING THE LINE. If you have the opposite, oil will follow the downward path and fill the equalization line)

    It IS possible yet I personally am not worried about oil until it reaches THE OPPOSITE SIDE OF THE DIAPHRAGM in the TXV.

    Unless you have something really, really, really strange going on, I can't see any reason for a further failure of the present txv. But I am assuming the system is not full of "trash" from a burnout.
     
    Last edited: Mar 16, 2014
  20. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Hey HVAC Tech:

    How are you?

    They can clog and be way over heated as you note above.

    Mark
     

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