When is it time to replace compressor or whole base unit?

Discussion in 'General Discussions' started by Jerry_NJ, Dec 16, 2012.

  1. Jerry_NJ

    Jerry_NJ Member

    I have a two speed Waterfurnace GeoThermal that is approaching 20 years old. It ran without any maintenance other than sir filters for about 15 years, then in the next couple of years I had to replace the three speed forced air fan (for which WF could not produce an exact replacement so I had to pay extra to retro fit a newer unit) at about $1,200. Then a couple of years later I had to replace the two ground loop circulation pumps (this had some misdiagnosis problems - I'm a retired electrical engineer or these errors would have gone unnoticed) at an additional $1,500 or so (I would have to look up the cost is anyone wants to do a financial analysis). Still given the amortized cost of repairs over 20 years is about $120 per year, no more than what an oil furnace tune up cost - I guess - not a big issue.

    But, what next, the compressor? As you know the whole unit, other than the loop, is inside the house so a replacement of the compressor doesn't leave me with a rusted housing, the unit look new (to my old eyes at least).

    I seek any advice on when one should consider the unit about ready to fail, and the best approach forward, including replacing the complete inside equipment - maybe with a variable speed compressor which I think is a giant step forward in reliability, regardless of the fact my two speed compressor is still running about about 20 years.

    It looks like new designs, even two speed, can give me a significant improvement in efficiency. In low speed my unit delivers a COP of about 4.0, a newer design may give me 5.0 or even better, but at what cost?

    I think I can not retrofit an upgraded compressor in my existing unit (I can provide the model number is any interest is generated), but if I can that would be another consideration.

    I think the installer of my Waterfurnace did a super job, a real crafstman. But, he has changed form Waterfurnace to Climatemaster... suppose I can change there too, the ground loop doesn't care and I'm sure both make a unit that fits my available space.

    20 Years go I paid about $12,000 for my Geothermal, I estimate a similar installation today would run over $25,000. But, I have a ground loop so it may be I can get a replacement furnace and pumps for under $15,000. Am I anywhere in the ballpark on these estimates? I will contact local (not real local as I live in a rural area) contractors to get a price/bid, but will appreciate some insights from others first.

    Hope my unit doesn't fail while I'm making a study. That will bring the whole subject to an emergency answer, not the best way to go.

    I'm new here, but not new to residential geoghermal heating and cooling (hot water is another story - that too has improved in the past 20 years).
  2. johnny1720

    johnny1720 Member

    Jerry you will get lots of great answers from these people. Just stay tuned.
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    We are doing this all the time, exchanging older inefficient units with newer ones, connecting to the old loopfield. With significant increased efficiency, tax credits and new 10 year warranties out there, it is usually well worth it. We just replaced a 5 ton Hydron with new DSH setup and tanks for about $15K. But it depends.....
    The only problem can be that the newer units pull more heat out of the ground due to higher efficiency and might require different flow. Your groundloop needs to be checked for flow, check again for sizing, make sure that the old unit was not oversized.
  4. Jerry_NJ

    Jerry_NJ Member

    Thanks I"m sure a 3 ton is big enough for my house, that has been proven. I don't know either Hydron or DSH, are they HP suppliers? I don't understand the statement: "The only problem can be that the newer units pull more heat out of the ground due to higher efficiency..." that is higher efficiency at the same heat output should be drawing less heat from the loop. As you noted, that may mean a different flow, i.e., less which is less energy to pump, thus more overall efficiency. I had to replace the two stage loop pumps a bit over a year ago, the loop was tested and recharged at that time.

    Keep in mind too, my old unit is not that inefficient, it has a low speed COP of about 4. A new unit may have 4.5, I'm not interested in paying thousands more to get the COP over 5. Of course with Obama in the White House for 4 more years we may yet see his promise of "the electric rates will necessarily skyrocket.." due to the death of the coal industry through regulations, he will not even have to get his failed "Cap and Trade" bill through, just rule by regulation and executive order.
  5. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    The more efficient a heat pump is, the more btu's have to come from the ground. So some thought has to go in to the replacement, as mentioned.

    But yes, replacements are common enough now that the industry has been established for that long. And your pricing is in the ballpark. When to do it is a tough call.

    I don't try to upsell, but at the same time one can usually tell by the history of the unit, when it is getting time to replace it.
  6. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Hydron is a brand, DSH means Desuperheater, a way to have a majority of your hot water made by the heatpump. What worries me that your have 2 to circulate your water for a 3 ton capacity. Usually this should only require 1 circulation pump. You need your loopfield and your flow checked out by someone who understands it.
    Get operational cost estimates to see what your payback is after tax credit with the newer high efficient units.

    Please, no matter what your political orientation is, take any kind of political venting elsewhere....
  7. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Like Doc, I'm not sure your installer knew the biz so well if he has 2 pumps on a 3 ton loop system. So we know 3 ton is large enough how do we know 2 ton won't do?
    15K for Docs 5 ton suggests your 3 ton would be a little less.
  8. Jerry_NJ

    Jerry_NJ Member

    The two pumps was a Waterfurnace design, not an installer option. The pumps are in series, one runs for low stage I, both run for high stage 2, the idea being to maximize efficiency via a reduced pump load when less heat is being extracted (or returned) to the ground. I believe newer units, not necessarily better units, use a single pump (best I recall what the repair tech told me). The repairs have been done by what WF calls a Geopro (best I can recall) and the owner came on my first call for help at about the 15th year of operation. The installer had moved from WF to Climatemaster, otherwise I'd have called him. I wasn't impressed with the service and trouble shooting done by the Geopro on the second call at about year 17 to get the loop pumps replaced - while they had wear after than many years, that wasn't what shut ht unit down. I replaced them anyway and walked the technician owner through my review of the errors made and he came back and made corrections an no charge. So, I agree, some don't know their "biz" but that applies to the repair not the installer. In fairness, my unit is "old" and these guys may not work on them often - said another way, isn't it great the reliability is so good the repair technicians are not familiar with them. I'm not a HP tech, but I can read and understand schematic diagrams and processor controlled logic.

    The appeal for a new unit seems mostly to be the 30% tax rebate, a new compressor would not qualify for a rebate yet may still be a lot of $$.

    I've joined this forum mostly to learn how many years compressors have help up for others, perhaps my system is at the head of that pack. I am also reviewing what the new breed of GSHP have to offer, and so far I'm not impressed. One long tread on this forum complains about the noise of the compressor, a scroll. This is only one data point/opinion, but I was thinking, wouldn't it be nice if I could upgrade my existing unit with a new scroll (Copeland?) compressor, maybe not so good.
  9. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    We have seen compressors still operating in 25-50 year old heat pumps. Technology has changed little except for the PC boards, older units are usually easier to service.
  10. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    It is not about just swapping out a compressor. I am sure it could be done but at what cost. These machines are tuned. Matching coils, blowers, piping and pumps together to achieve the best possible heat transfer. An example would be your replacement blower motor issue.

    The first thing that needs to be done to make your quest worthwhile, is to do a heat loss/gain.

  11. Jerry_NJ

    Jerry_NJ Member

    Thanks, I may step back and mostly read for a while. I have found this forum interesting and informative.

    If my compressor is good for 25 years, that's long enough for me to sell the house. I'm getting too old to deal with a two story house in a cold climate anyway. Maybe I'll move to a warmer climate...and just need cooling.

    I understand the need to keep non-technical political (news) out of this blog and will do so going forward. I apologize for the slip.
  12. digger

    digger New Member

    I understand this post is a few years old, but I'm hoping Jerry_NJ is still receiving notifications and can reply to this. ;-)

    I, too, just had my compressor replaced and have been looking into seeing if the tax credit applies to it. I haven't been finding any information related to specifically "repair or replacement." Your comment that I quote above is the only thing I found that specifically mentioned it. Can you tell me whether the above is your opinion, or if you know that as fact? Any information you can provide would be appreciated.

    Thanks so much.
  13. Jerry_NJ

    Jerry_NJ Member

    I replaced the complete unit with a Series 5 Waterfurnace. Part of the decission driver was the understanding repairs do not qualify for a tax credit. Also for my 21 year old unit a replacement compressor was not provided by Waterfurnace. In the previous 5 years I made about $3,000 in repairs, no tax rebate was applied for, again my understanding. Some of the repairs were for the ground loop, i'm making use of this investment with the new unit.

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