when should I reaplace my 17 year old trane Central AC? unit

rollandelliott
rollandelliott Solar Expert Posts: 834 ✭✭
in Energy Use & Conservation #1
http://www.google.com/url?sa=t&rct=j&q=energy%20star%20central%20air%20conditioners&source=web&cd=3&ved=0CHAQFjAC&url=http%3A%2F%2Fwww.energystar.gov%2Fia%2Fbusiness%2Fbulk_purchasing%2Fbpsavings_calc%2FCalc_CAC.xls&ei=nmExUIG8PKLW6wHIi4GICg&usg=AFQjCNFEDWG6mCZ9wbT5PD_mkOsG2wSrYA&cad=rja

states that payback is only 3.3 years. I just paid $600 to add refrigerant to my AC unit. Aparently it leaked out a little after 17 years of use.

It is a 3 ton unit. If I have to pay to get it fixed again I'm deffinetely going to replace it, any recommendations for a 3 ton unit!??
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #2
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Well minisplits are great but may require modification you don't want to make, most have upto 4 wall unit capable 3 ton outdoor units.

    I run a Trane 2 speed and it is higher seer and a pretty efficent.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #3
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Interesting I did not know they made minisplits that big. I always assumed they were for smaller 2 room or less applications. I guess instead of having a spiderweb of duct work in your home you replace it with a web of refrigerant lines!

    Actually the mini splits have competition
    http://www.energystar.gov/index.cfm?c=most_efficient.me_cac_ashp

    shows some central AC units with Seer ratings of 21 and up!
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #4
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Before installing my Mitsubishi mini split I found a site that was dedicated to HVAC reviews (sorry, don't have the site address anymore, just google hvac reviews/furnace/ac reviews). Mits had 5 reviews or so, there were many (21?) pages of Trane problems. Old units were and are top of the line, but the new Trane stuff sounds horrible...run, don't walk away from it. Installers even saying they no longer carry it because of all the problems.

    The concensus seemed to be, if you have older Trane equipment and it's working, keep it, but don't upgrade to new Trane stuff.

    Ralph

    (spoiled by Mitsubishi)
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  • Ken Marsh
    Ken Marsh Solar Expert Posts: 114 ✭✭✭✭
    #5
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Your chance of getting another 17 years without recharge is not good.
    There is virtually no small leaks like that.
    Oil circulates with the refrigerant and coats everything. Trash in the oil plugs small leaks.
    So leaks are usually cracked lines with the crack perpetuating or charging fitting, etc.
    Have you frozen up the evaporator coil? This can cause a leak.

    But if you can find the leak they are usually quite easy to fix.
    Look for oil spot on the lines.
    You got to have the equipment.

    Seems like the main benefit of the mini splits is that you can run them with solar arrays.
    They don't have the large inrush upon start.
    In a few years all refrigeration will be this way.
    Have friends in the industry who report that their R&D is full of inverter driven stuff.

    I am retrofitting a 34 year old heat pump.
    It is getting a 3 phase compressor, VFD and some other things.
    Have it running with manual control and it looks good.
    Still have to get the controls adapted.
    It starts with 0 amp inrush and the amps ramp up with rpm.
    Looks like it is drawing about 75% the power as the single phase compressor.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #6
    Re: when should I reaplace my 17 year old trane Central AC? unit
    rollandelliott wrote: »
    I just paid $600 to add refrigerant to my AC unit. Aparently it leaked out a little after 17 years of use.

    It is a 3 ton unit. If I have to pay to get it fixed again I'm deffinetely going to replace it, any recommendations for a 3 ton unit!??

    One reason that the recharge cost so much is that it uses old type Freon refrigerant which is no longer being manufactured for environmental reasons. The only supply in the US now comes from recycling from older units when they are scrapped, along with stocks that people have stored. The next time you have to recharge, the cost will have gone up again.

    Unlike car A/C units in which it can often be practical to switch over to a replacement refrigerant, stationary units are stuck by design with their original Freon type.
    Going to a newer, more efficient unit will also get you into a lower long term cost for refrigerant in case of leaks.
    SMA SB 3000, old BP panels.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #7
    Re: when should I reaplace my 17 year old trane Central AC? unit

    "Have you frozen up the evaporator coil? This can cause a leak.

    But if you can find the leak they are usually quite easy to fix.
    Look for oil spot on the lines.
    You got to have the equipment."

    Well I was looking over the repair guys shoulder when he did the repair work on my exsisting compressor unit, but had to leave before he put in the 2 lbs of refrigerant/r22. He could not see any leaks., but sold me some sealent he injected in for $120, said hopefully that would fix the small leak. I have replaced a car condenser so I know what you mean by checking for oil leaks. That is actually how I found the leak on my car.

    My inside evaporator coil did freeze so if that is where it leaks than I'll just wait. Ripping that condensor coil out would be a one or two day job easily.

    I just spoke to a HVAC sales guy and he came to my home. Quoted $9,000 for a new HVAC system. TOld me that I would have to replace my furance too! There's gotta be a way to take out the exsisting blower and replace it with a variable speed one.

    Ebay has lots of HVAC high effcient units, but they tend to me incomplete. I saw a 3 ton 22SEER compressor unit, but it did not come with air handler. From everything I have read if you dont' match components than the effciency rating goes down the drain.

    Ken sounds like you have experience frankensteining systems, do you know where I can get a variable blower fan?
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #8
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Since these new HVAC systems use Refrigerant that does not deplete the ozone is installing one, now a DIY possibility? With R22 I think they only sell it to people with HVAC licenses. I've recharged my Car's AC refrigerant, Doing so for a home can't be that much more difficult IF I can actually buy the refrigerant.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #9
    Re: when should I reaplace my 17 year old trane Central AC? unit
    rollandelliott wrote: »
    Since these new HVAC systems use Refrigerant that does not deplete the ozone is installing one, now a DIY possibility?

    It is a relative difference, not an absolute one. The newer refrigerants do not deplete the ozone layer as much on a pound-for-pound basis but they still have an effect. Regulations may still require you to pump down and recycle other refrigerants too. Check your local laws on this one. Getting the charge amount correct can still require a pressure gauge set and other equipment, and over or undercharging can damage the compressor.

    Matching the compressor size to the coil size and the air flow rate is indeed important, and a mismatch can either overload the compressor or cause the coil to freeze up. So putting together a system from parts requires at least a minimum level of engineering calculations.
    SMA SB 3000, old BP panels.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #10
    Re: when should I reaplace my 17 year old trane Central AC? unit
    rollandelliott wrote: »

    I just spoke to a HVAC sales guy and he came to my home. Quoted $9,000 for a new HVAC system. TOld me that I would have to replace my furance too! There's gotta be a way to take out the exsisting blower and replace it with a variable speed one.

    That is a bit pricey, I had mine replaced with an air sourced heat pump 2 speed compressor system for right at $6500. My installer told me that the payback on going much higher than 17 seer is minimal and the cost is much greater proportionally. YMMV A gas fired heater system was less money BTW
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #11
    Re: when should I reaplace my 17 year old trane Central AC? unit
    solar_dave wrote: »
    That is a bit pricey, I had mine replaced with an air sourced heat pump 2 speed compressor system for right at $6500. My installer told me that the payback on going much higher than 17 seer is minimal and the cost is much greater proportionally. YMMV A gas fired heater system was less money BTW

    Gas fired cost depends on whether it is piped natural gas or propane. If the price of propane is high enough, an electrically powered heat pump can deliver heat at lower cost, even though the initial cost will be higher.
    SMA SB 3000, old BP panels.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #12
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Yeah that is what I thought. I can buy two mini split dual zone systems for $4,200 and install myself. Getting central air equipment is a hassle, everyone I call wants me to be a dealer/installer.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #13
    Re: when should I reaplace my 17 year old trane Central AC? unit
    rollandelliott wrote: »
    Since these new HVAC systems use Refrigerant that does not deplete the ozone is installing one, now a DIY possibility? With R22 I think they only sell it to people with HVAC licenses. I've recharged my Car's AC refrigerant, Doing so for a home can't be that much more difficult IF I can actually buy the refrigerant.

    Yes, you can. I bought a tank of R-410a plus new manifold about 2 years ago from this place: http://www.r-410a.com/

    No license required to buy this stuff, I checked and double-checked, including finding a FAQ on the EPA's web site (here is one).
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #14
    Re: when should I reaplace my 17 year old trane Central AC? unit

    thanks, what did you do with the left over refrigerant. My 3 tons system uses about 7 pounds. I guess I could ebay it. a 25 lb tank would still have around 18 lbs left over.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #15
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Since my purchase of a mini-split has been on hold since then I still have the full tank, manifold is still in the packaging. I may hold off for another year or two to see if whole-house systems catch up which might obviate the need for mini-splits all over the house.

    Anyone wanna buy my stuff? :blush:
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #16
    Re: when should I reaplace my 17 year old trane Central AC? unit

    put it up in the for sale thread on the main page or ebay it. I did some number crunching as well baseed off costs on http://ingramswaterandair.com/
    I think economically it is best if I let my current system go another 5 to 6 years or until it dies and then put in a new system. Replacing it early would not save me $$$.
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  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    #17
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Hold off as long as you can if you want to buy a conventional ducted system. Many manufacturers are having problems with leaking evaporator coils from formicary corrosion. The tubing is much thinner than in the past and leaking prematurely. They are working on a solution.
    No problems yet with minisplits. Fujitsu, Mitsubishi, & Daikin have up to 4 ton heatpump inverter units available with up to 8 evaporators connectable. Or you can duct the concealed ceiling types. They are the best bang for the buck if you live in a warm climate where A/C is a necessity. High efficiency ratings .

    If your system continues to leak you may have to replace as the cost of R-22 is skyrocketing. You can expect the cost of a recharge to double next year as production will be half of what is was this year.
    Refrigerant leak sealer is bad news, it is a contaminate as far as I'm concerned only used as a last resort. Kills compressors and plugs all those small orifices in the TXV valve.
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  • Ken Marsh
    Ken Marsh Solar Expert Posts: 114 ✭✭✭✭
    #18
    Re: when should I reaplace my 17 year old trane Central AC? unit

    You got me to looking at refrigerants.
    See R-410, the newer stuff, is about $6.00 a pound.
    R-22 is about $9.50/lb.
    It has really gone up.
    Bought a 30 lb cylinder this spring for about $6.00/lb.
    Probably is the hot weather that drove it up.
    The majority of the air condx units out there are still R-22.

    There are a lot of options now.
    Think I will try the R-22a.
    Ordered a 30 lb equivalent cylinder.
    They didn't ask for my license so I assume anyone could buy.
    It is actually 10 lb which they say replaces 30 lb of R-22.
    It's average molecular weight is only one third that of R-22.
    R-22 is heavy because it has so much Chlorine in it, which is also what makes it environmentally unpopular.
    Understand 22a is a mixture of many things with the major constitutes being Isobutalene and propane.
    So it is flammable which is ok with me.
    I have used straight propane and it works good in about the same range as R-22.
    It is hard to get straight propane now.

    Anyway, the reason for my experimentation is their claims of higher efficiency.
    The claims run as high as 40% more efficiency.
    This is high, there is not that much inefficiency to pick up.
    But I do know that standard air conditioners run at about half of their Carnot efficiency.
    Maybe we can pick some of that.
    I would be happy with 10%.

    Rolland, You ask about matching air coils with the condensing unit;
    For air conditioning you will be ok as long as you match the tonage.
    For heat pumps you better use the specified air handler.
    This is because the refrigerant flows the opposite way heating vs cooling.
    They play tricks in the design to get the two to balance out.

    As for speed controllers; What do you want to control? The outside condenser fan or the inside fan?
    Generally, if it is a PSC (Permanently Split Capacitor) motor you can use something like ebay # 390413156432.
    But they do not work good on shaded pole, regular induction or split phase motors.
    Most aircondx equipment in the last 25 years uses PSC motors.
    Do not try these speed controllers on the compressor even though it probably is PSC.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #19
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Interesting I didin't even know there were replacements
    Just found the following
    Dupont ICEION MO-99
    NU22B and
    22a
    Honeywell Genetron 407C (R-407C) or Genetron 422D (R-422D)

    Maybe next time my system leaks I will just get the refrigerant changed over. Question is which is the best alternative?

    Honeywell claims 407c is the most effcient replacement:http://www.honeywell-refrigerants.com/applications/r-22-retrofits/

    The cheapest price of R22 I found was on ebay for a 30 lb container about $12 a pound. Where are you getting it at $9.50 a pound?

    The repair guy charged me $150 a pound!!!!! Now that I'm educated I won't let that happen again. This is industry practice though as other companies charged similarly.

    As far as the fan I was talking about the blower fan, but I'm not going to worry about that until the system has future issues.
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  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    #20
    Re: when should I reaplace my 17 year old trane Central AC? unit

    R-22 is being phased out that is why the cost is rising.
    http://www.epa.gov/ozone/title6/phaseout/22phaseout.html
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #21
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Yes I realize this and the AC repair people hype it up a lot! Too bad they don't tell you that the increase per pound is about $4 to them, pocket change compared to the service bill of $450. :grr
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  • Ken Marsh
    Ken Marsh Solar Expert Posts: 114 ✭✭✭✭
    #22
    Re: when should I reaplace my 17 year old trane Central AC? unit

    It seems like the major issue with the replacement refrigerants is whether or not you require it to be non-flammable.
    If you want it to be non-flammable you need to load the module up with Chlorine, Bromine or Florine.
    This makes it heavy, expensive, lowers efficiency and gets you in trouble ecologically.
    As for me, I do not consider a couple pounds of flammable refrigerant to be a problem.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #23
    Re: when should I reaplace my 17 year old trane Central AC? unit

    after some more digging around
    407c is only about 2 to 3 percent more effcient according to this 1998 purdue paper
    http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1381&context=iracc

    i don't really care if the closed loop refrigerant is flamable or not. I've got 8 gallons/40 pounds of gas in my garage right now, never loose sleep over that.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #24
    Re: when should I reaplace my 17 year old trane Central AC? unit

    The one issue with flammable refrigerants is that many (if not all?) are heavier than air. I believe that many of the "issues" that we are seeing are really the result of crony capitalism--creating artificial constraints on what only a decade ago were life saving chemicals (Freon; inert, not much of a suffocation risk, even used as a fire suppressant in times past, even used in asthma inhalers vs the other major refrigerants of the earlier years that are dangerous like ammonia and/or flammable, etc.).

    If you use propane or other flammable refrigerants--Watch for areas that can collect gases (basements, earth berm homes, etc.). I would suggest installing a propane alarm and possibly a low O2 level alarm in such spaces.

    I agree that a few pounds of propane is not the worst thing in the world--and most system leaks are going to be sssslllloooowwww (unless somebody pulls a line loose). But--With all these "new" and reborn older technologies, there are risks that we have not had to worry about for decades.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #25
    Re: when should I reaplace my 17 year old trane Central AC? unit
    LucMan wrote: »
    Hold off as long as you can if you want to buy a conventional ducted system...

    That's my plan. My heat pump upstairs is still chugging along ok - although there are odd times where it can't seem to cool just a few degrees even when the outside temps aren't that hot. I wonder if it freezes up but only happens once in a while. The downstairs A/C is the one that is dead due to a minor crack in the evaporator. I could spend $500-1000 to get it replaced but I wanted to avoid dumping new money into it @ 12 SEER when I could upgrade to double that. My plan for 2 years has been to covert to mini-splits room by room but I keep telling myself that the big splits will catch up "soon". It will be far easier and cheaper to go that route - I hope.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    #26
    Re: when should I reaplace my 17 year old trane Central AC? unit

    Don't count on the splits catching up to the mini splits in technology & price, Nordyne (Maytag http://www.maytaghvac.com/Maytag-iQ-Drive-Air-Conditioner-p/psa4bi.htm) already has a unit available for big$. The latest technology is CO2 refrigerant, should be in the US in 2-3 years. The split unit will most likely bypass the 410A inverter style units completely, and go to CO2 technology.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #27
    Re: when should I reaplace my 17 year old trane Central AC? unit

    " It will be far easier and cheaper to go that route - I hope. "

    Well it would deffinetely be easier to replace exsisting system instead of making an entirely new one. As far as price SEER 20 Central AC units are already available. They are about double the price of standard SEER 13 units. For example SEER 13 system 3tons is around $2000 cooling only. Same high effciency SEER 20 unit is $4000. If you are in the south USA you can easily break even in 6 years if you do the install yourself.
    Hopefully the price will come down more in the future reducing the payback time.
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