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  1. #1
    Join Date
    Apr 2005
    Location
    Houston, TX
    Posts
    18
    Okay, so I'm about to buy a house (as the user name suggests) and it currently has an OLD Arkla Servel unit that doesn't work. I wasn't able to find much of anything on Google about NG chillers in general. Are they more or less costly to run than electric split systems? Anybody in Houston service these? Are parts even available anymore? I suspect I'll probably end up replacing it unless it is cost effective to fix and operate it.

  2. #2
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Replace it, those things cost MUCH more in combined gas and electricity usage to run than even a new 10 SEER system would cost.
    You would also be very lucky if you could find anyone that knew how to repair it, or could get parts for it if anything needed replacing other than the thermocouple or the gas valve. The gas side of the system is easy, but if the problem isn't with the gas side, you will be hard pressed to find anyone that knows ammonia absorbtion systems, is certified to work on ammonia systems, and is willing to work on a residential system he probably can't get the parts for anyway.

    We had a ton of those things up here in the DFW area too. Lone Star Gas used to push them back in the days when they were at war with all the electric companies. I'm told that Lone Star Gas was about the only place that you could get service on them from too, then they stopped doing service work in the late 80's and just left everyone hanging in the wind as far as service on the damn things went.

    Man, just thinking about those things makes my back hurt and my nose twitch. They are heavy as hell and full of ammonia.
    If more government is the answer, then it's a really stupid question.

  3. #3
    Join Date
    Apr 2005
    Location
    Houston, TX
    Posts
    18
    Originally posted by mark beiser
    Man, just thinking about those things makes my back hurt and my nose twitch. They are heavy as hell and full of ammonia.
    Well....that sounds like its going to make disposal of it an absolute peach.

    Thanks for the info!

  4. #4
    Join Date
    Jan 2002
    Location
    Ft.Worth,Tx
    Posts
    4,584

    Talking Lone Star Gas

    Yea, they really liked them as long as they worked. Belts,low water shut off and not to forget gas powered to heat the ammonia and cool the water...But, in 1987 I pulled 15 of them off Lone Star Gas Office in Garland and replaced them with G.E. Heat Pumps.

    I would replace it with American Standard or Trane..

    http://www.americanstandardair.com
    http://www.amstd-comfort.com

    Check these sites for a dealer in your area...
    "Everyday above ground, is a good day".
    "But everyday that you have made a difference in someones life, may insure you stay above ground a little longer".<aircooled>

  5. #5
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,325
    We had a ton of those things up here in the DFW area too. Lone Star Gas used to push them back in the days when they were at war with all the electric companies. I'm told that Lone Star Gas was about the only place that you could get service on them from too, then they stopped doing service work in the late 80's and just left everyone hanging in the wind as far as service on the damn things went.
    I was just a kid when those Arkla-Servel residential chillers had their heyday. The neighbors behind our house had one. Seems I remember Lone Star touting them as being more quiet and cheaper to operate than an all-electric counterpart. Perhaps the cheaper part was true back in the day when natural gas was dirt cheap, but as time wore on our neighbor's unit got louder and louder. It also seemed to break down a lot. It was installed in the early seventies and was yanked out by 1980 or so.

    I also remember Lone Star pushing front and back yard gas lamps, the ones with the mantles like on a Coleman camping lantern. Often the neighbors that had one would neglect them, and the mantles would burn away to where there was nothing but a blue flame shooting out of the tube where the mantle once was attached.

    Times sure have changed! No more Lone Star, and now the gas company (Atmos) would rather talk to you about saving gas than finding ways to burn it!
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  6. #6
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,321
    There are few if any companies here in Houston that still work on the Arkla Servel units. The best thing is to replace it with a properly installed system. This usually means new ductwork adding return air capacity electrical upgrades the works. You are looking at from $10,000 to $20,000 for a quality job.

    I have replaced many of these units over the years and it does not pay to try and short cut the process. Are you in the Meyerland or Tomball area that is where most are located although they are scattered around the area.

    You will need to have the home evaluated for proper sizing not just replace what is there or rule of thumb. Most of these systems were sized out too small for the house because they were so cheap to operate in their day. The ductwork also needs to evaluated most likely undersized and poorly and insufficiently insulated. Since this unit was installed in the 60's or 70's you probably have metal ducts some or all of which could be retained; it will just need to be tightened up and added to and re-insulated.

    If you choose to buy this house and replace the system do not go the quick cheap route you will be very sorry in the long run.

  7. #7
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304
    >>Most of these systems were sized out too small for the house because they were so cheap to operate in their day.

    Could you explain a little? I'm confused, it seems to me if they were so cheap to operate there would be a tendency to oversize, not undersize.

    Thanks much -- P.Student

    P.S. I lived 20+ years in the Meyerland area but as luck would have it, never ran across one of those relics. Many homes were built in the 50's and a few were built without central air.

  8. #8
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,325
    Could you explain a little? I'm confused, it seems to me if they were so cheap to operate there would be a tendency to oversize, not undersize.
    Here's my take on it, P. Take yourself back to the 60's and 70's when these units saw their heyday. The gas companies promoting them wanted to increase their installed base of these things...so they could sell more gas! And what would undersizing a system for a house do? Move more gas! Why? Because, as you well may know, an undersized unit runs almost constantly during hot weather. An oversized unit cycles. Yeah, one could argue that the on time of an oversized absorption chiller offsets (due to larger burner size, etc) the off time and concurrently the constant run time of an undersized system for the same size house, but that's debateable.

    Depending on how these chillers work, they may cycle on maintaining a consistent chilled water loop temperature vs. indoor thermostat cycling. An undersized unit would burn nearly constantly to maintain the chilled water loop temp, whereas an oversized unit would cycle, as there's likely a thermal lag factor between the time the unit satisfies and the water loop has warmed enough to demand more cooling. As a result, it's possible a residential absorption chiller that is oversized would use less natural gas than its undersized counterpart.

    It's also possible whoever installed these things in the Houston area knew a little about psychometrics and purposely undersized the units so they would run more and offer better dehumidification. Perhaps it's also better for this kind of chiller to run more than not, due to the nature of the absorption process and the start up time involved after it has been at rest. As it is I don't know enough about these units as I should, although I'll likely not ever work on one (most of them in my area are either yanked out, dead, or dying, and good luck finding somebody who can work on them!).

    But, just remembering the days when natural gas companies went to extremes to sell gas, my theory remains these things were undersized to move more gas through residential meters.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  9. #9
    Join Date
    Mar 2004
    Posts
    1,042
    Wouldn't an undersized chiller impair dehumidification by letting the water loop slip to warmer temps under heavy load? That would leave you with not-so-cold coils inside. You could dehumidify in mild weather but not in really hot weather.

  10. #10
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,321
    Sorry guys nothing as lofty as engineering for humidity control or as nefarious as trying to sell more electricity.

    Pure and simply in the early days around here they sized system smaller. Manual J was not as sophisticated it took just a few minutes and as much as 800 to 900 sq. ft. per ton and that was with single pane windows and little or no insulation in the attic and walls.

    It wasn't until the mid to late 70's that load calcs were more in use and more involved. After the first oil crisis energy efficiency became a big deal and we started sizing up insulating better and sealing homes.

    I remember doing loads for new construction in early 70's half a page basically number of windows square footage and direction. Took all of 10 minutes without a calculator.

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