sudden coolant failure after adjusting thermostat ??
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  1. #1
    Join Date
    Dec 2006
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    Toronto, Canada
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    29

    Confused sudden coolant failure after adjusting thermostat ??

    Wife is house-sitting her Mom's place in north Toronto, while her Mom is away for a 6 week vacation in Africa.

    Her mom runs the AC too cold for my wife so I re-programmed the thermostat to be 75 degrees from its original 72 degree setting.

    Next day the house is unbearably warm - 86 degrees inside according to the thermostat. I triple check the thermostat, do a hard reset, re-program and also try temperature over-ride. The thermostat indicates that it is cooling. It turns on the blower fan and the outdoor AC unit.

    The supply plenum above the cooling coil is room temperature, as is the cooling pipe from the outdoor AC unit to the coil. The fan on the outdoor unit runs, but blows cool air out the top, not warm air like it should while removing heat from the house.

    To me that indicates a total loss of coolant, but that seems highly unlikely given that only hours earlier, the AC produced air that was ice cold. Would have to be a sudden catastrophic failure, but there is no sign of any recent leak/damage that I can see in the lines from the external unit to the coil in the supply plenum.

    Something doesn't seem to add up here. Seems to be too much of a co-incidence that the cooling fails suddenly after I adjust the thermostat a couple degrees.

    Am I missing something obvious here?

    Getting the unit serviced may take several days, as we first have to make contact with her Mom to authorise any work/repairs.

    Unfortunately, my wife is living at the house full time, and it's too hot for her to sleep! She can't come home, since our house has been gutted and is undergoing a major rennovation right now.

    Furnace - Lennox Complete heat combination gas water heater/furnace
    Outside AC unit - Lennox (don't have a model number)
    Thermostat - Lux500

    All HVAC is original equipment from when the house was built about 5 years ago.

    Any ideas?

  2. #2
    Join Date
    Sep 2003
    Posts
    1,660
    Any ideas?

    A few

    My advice to you would be what I tell my customers when they call....
    Turn off the a/c if you haven't already....
    and contact a local HVAC Contractor for a service call.


    The reason being the problem could be a simple fix to the contractor but something out of your league to repair.

    The problem could be anything, that's why you need to turn it off to save yourself some potential headaches from running the a/c without it working
    and causing further damage to the equipment.

    Don't put the cart before the horse and assume a major problem with the unit until it is diagnosed as that

    Might cost you a hundred buck to have it looked at
    but that might get it fixed sooner.

  3. #3
    Join Date
    Sep 2001
    Location
    kalamazoo,mich
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    2,174
    Call a service tech, you're in over your head.
    Have you hugged the Earth today?
    Donny Baker rules

  4. #4
    Join Date
    Dec 2006
    Location
    Toronto, Canada
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    29
    Quote Originally Posted by small change View Post
    Any ideas?

    A few

    My advice to you would be what I tell my customers when they call....
    Turn off the a/c if you haven't already....
    and contact a local HVAC Contractor for a service call.


    The reason being the problem could be a simple fix to the contractor but something out of your league to repair.

    The problem could be anything, that's why you need to turn it off to save yourself some potential headaches from running the a/c without it working
    and causing further damage to the equipment.

    Don't put the cart before the horse and assume a major problem with the unit until it is diagnosed as that

    Might cost you a hundred buck to have it looked at
    but that might get it fixed sooner.
    I figured we would have to call a tech - but at the same time, wondered if I might be missing something obvious and embarrassing - like "did you wife turn off the pipe going in/out from the water heater to the furnace blower compartment?"

    I've never seen a Lennox "complete heat" system so for all I know, it may also act in reverse somewhat like a heat pump and use the heat removed from the house to heat the water. The outdoor unit, however, is connected to a separate coil above the "water radiator" gizmo in the blower compartment.

    Wife's mom has a tech she normally uses. Wife found the number this morning, and will set up an appointment. I wonder about this "tech" though. No number posted on the unit itself, and the air filter was installed backwards. Not sure if the tech put in the filter, but I'm sure her mom didn't- she asks for help to change a light bulb - seriously!

    Noticed in the daylight before leaving this morning, that the outdoor unit needs to be cleaned -the fins have a thin coating of mostly cotton-like debris - probably dandelion leaves that have been floating around. I would have cleaned it this morning if I could find a soft brush attachment for her vacuum hose.

    I did not occur to me that running the AC might cause further damage. Duh Thanks for the tip. Fortunately, I did turn off the unit last night as it seemed a waste of electricity - especially running all the time since it never reaches target house temperature.

    Will post the result of the service call.

    Thanks

  5. #5
    Join Date
    Dec 2006
    Location
    Toronto, Canada
    Posts
    29
    Quote Originally Posted by small change View Post
    Any ideas?

    My advice to you would be what I tell my customers when they call....
    Turn off the a/c if you haven't already....
    and contact a local HVAC Contractor for a service call.

    Don't put the cart before the horse and assume a major problem with the unit until it is diagnosed as that

    Might cost you a hundred buck to have it looked at
    but that might get it fixed sooner.

    It's going to cost $119.

    I convinced wife to let me choose a professional for her mother-in-laws AC service call. I went on an internet site where former clients rate Toronto area contractors ( http://homestars.ca ) , and called the top 3 HVAC businesses in the area. I chose a small, family owned company, run by 3 brothers, that seemed the most competent, helpful and customer service oriented of the places I contacted. They are $20 more than others, and can not come until end of the week.

    I found out the "tech" my mother-in-law uses has a day job at Sears as an appliance repair man, and is somewhat of a jack (hack?) off all trades. Found out this is the same guy that after removing my sister-in-law's dishwasher, simply capped the existing electrical wires, with a separate wire nut on each wire, leaving those wires lying on the ground in the dishwasher cavity immediately adjacent to the sink! It was going to be left that way for a few weeks until the new dishwasher arrived. !!!

    I just about freaked as her sister was also cat-sitting for us during our home rennovation. Hey - if it was only my sister-in-law there - LOL - but didn't want my favourite cat, to live up to his nickmake "the black death" I verified the power was off, and removed the wire nuts. I twisted the hot and neutral wires together with line man's pliers, then re-attached a proper size silicon filled wire nut, and wrapped it up with electrical tape specifically designed for wet/damp environments, then tucked the wires under a cabinet.

    Yes - I intentionaly created a short circuit so that she could not accidentally turn the power back on by flipping the breaker. If she tried , with the intentional short, the breaker would trip immediately and shut the circuit down again. I tested the breaker to be sure.

    With this AC though, I am definitely in over my head and need a real pro.

    Will report back on Friday afternoon.

    Thanks

    Dave

  6. #6
    Join Date
    Feb 2007
    Location
    Las Vegas,NV
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    744
    You sound crazy! It is rare, but I have seen breakers not trip from a dead short before. Why didnt you just spend a couple bucks and throw a junction box and a cover on the end of the wires???

  7. #7
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    Aug 2004
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    Kentucky, Michigan, Ohio, Arizona, Colorado, Nevada, and Califormia
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    I don't know if I'd have done that with the wires. Your intentional short had good reasoning behind it BUT.......breakers protect wires not people (except gfci) and if your breaker fails, say goodbye to the house. I have, in many years, seen a dozen or so breakers fail in the on position..even though the bar was off. I'd leave the hot and common separate, insulate each individually, leave the breaker off, and lock out the house panel (if you're afraid she'll accidentally turn it on.)
    "Surprised ?! If I woke up tomorrow with my head sewn to the carpet, I wouldn't be more surprised."
    Clark Griswold

  8. #8
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    Nov 2004
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    Michigan, Detroit Metro area
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    Yeah, the thing with the wires was just plain dumb. Should have just turned off the breaker and taped the wire nuts on and put a note over the breaker box not to turn that break back on until the new dishwaser was installed.
    What's my post count now?
    UA Local 636

  9. #9
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
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    Quote Originally Posted by lra View Post
    I don't know if I'd have done that with the wires. Your intentional short had good reasoning behind it BUT.......breakers protect wires not people (except gfci) and if your breaker fails, say goodbye to the house. I have, in many years, seen a dozen or so breakers fail in the on position..even though the bar was off. I'd leave the hot and common separate, insulate each individually, leave the breaker off, and lock out the house panel (if you're afraid she'll accidentally turn it on.)
    I agree. Ensure power to this circuit is off (verify with reliable meter) , cut off the exposed wire, cap the hot and neutral with separate wire nuts, tape each nut separately, then tape them together. Have a lockout tag on the breaker already before doing anything else and power is verifed off...do it the right way, not the stupid way.

    IOW, GO BACK ASAP AND REMOVE THE INTENTIONAL DEAD SHORT!!!
    • 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.

  10. #10
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    Mar 2005
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    burlington county n.j.
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    if thats a complete heat system you better makes sure the co you have coming out is familiar with them...

  11. #11
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    Dec 2006
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    New Jersey
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    there is nothing wrong with leaving dead wires capped with the breaker off. you are completly out of your mind. call your moms hvac guy. if you were my son i would be really upset with you if you called a strange company in. do i sense ocd? if your mother in law uses this guy its for a reason.

  12. #12
    Join Date
    Dec 2006
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    Quote Originally Posted by acmech13 View Post
    there is nothing wrong with leaving dead wires capped with the breaker off. you are completly out of your mind. call your moms hvac guy. if you were my son i would be really upset with you if you called a strange company in. do i sense ocd? if your mother in law uses this guy its for a reason.
    I'll get to the electrical - but first - the HVAC.

    My MIL uses the hack of all trades appliance guy for a reason - the reason being that he is cheap and takes cash after hours. And remember, he's not an HVAC guy, he's a major appliance repair person.

    Both my wife and roll our eyes when her Mom tries to recommend people to assist with our rennovation - despite the fact those same people have done terrible hack jobs on her house.

    Glad I tracked someone else down. Got a guy named Lou who bought the business out from his Dad. Lou was awesome - you can tell he loves his job.

    Identified that while the fan was starting up on the outdoor unit, the compressor was not kicking in. He tested the capacitor - it was at 50% of original rated capacity. Lou explained that as a compressor goes bad it also tends to degrade the capacitor. The capacitor had been replaced before, as the existing was an aftermarket. Lou did not have the correct capacitor with him, but found one (used i believe) in his truck we could temporarily use to test the problem. With the temporary capacitor the compressor kicked in, but would not stay on. In fact after about a minute the test capacitor fried discharging a lot of smoke. Given my MIL is planning to sell next year, Lou said it may be worth trying the right capacitor - and that might work temporarily. He'll return tomorrow or Saturday to try it.

    If that does not work, MIL's compressor is a 2 ton lennox, and so is the compressor we are ready to throw out at our place. Ours 15 years old, but it works fine. We plan to replace it within weeks, together with a new furnace, after we re-install ductwork in our currently totally gutted house.

    I am very pleased with Lou so far - think I may have found my own "HVAC" guy.


    And now to the controversial dishwasher electrical scenario! Note that the new dishwasher arrived long ago, thus no more non-terminated wires by the sink.

    The Canadians in the forum might reckognise the source of the suggestion to short the wires - believe it or not - Mike Holmes, of the show Holmes on Homes. The show is based on him fixing rennovation disasters done by others. This is not intended as anything but a temporary fix. Ideally I would have disconnected it at the panel, but that was not an option at the time.

    Twisting the wires together admitedly is a trade-off of risks. With the short - if someone tries to turn on the breaker and it fails to trip at that time - then yes, there would be a large problem. But remember - the breaker was left in the off position, and a breaker in the off position requires determined effort to turn on again. If the breaker flips off once or twice it is obvious something is wrong. As to taping the breaker, into the closed position, it is far more likely that the tape will come off, than the breaker will fail if someone accidentally tries to turn it on again. Unless the wire is shorted, sister-in-law (SIL) might go to the panel if there is a problem in another circuit, and simply try to turn on breakers that are off. It is often dark in such a situation. Turn breakers on until problem resolved, but forget the dishwasher circuit is now live.

    It is far more likely that someone would be electrocuted by wires they dont even know are live, beside the kitchen sink, the wettest, highest traffic area. Far more likely a marrette would slip off, or some moisture would find its way into the terminated hot wire, and then all you need is a small puddle, under the bare feet of where people, or worse yet - my cats spend most of their time.

    Marrettes simply do not hold properly on on a single solid strand wire. They were NEVER designed to do this. Using a marrette in this manner is truly crazy - even if you add tape - you still don't have the proper mechanical connection that a marrette was designed to create on TWISTED wire connections.

    I certainly understand why many people disagree, but think they are losing sight of the risks of the original situation, which is more likely to have more catastrophic results. Worst case scenario, you have a decent chance of escaping a fire, especially with multiple smoke detectors, but one mis-step on a wet, energised floor........ I'll take the fire, thanks.

    I'm sure there are still many here that won't agree - but again bear in mind - I did not have access to the inside of the panel, so in terms of pontential loss of life - this was IMHO the least risky option.

  13. #13
    Join Date
    Jun 2002
    Location
    Merrimack Valley, MA
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    105

    (wire) nuts!

    Sorry, shorted wires like that are an accident waiting to happen. Breakers are not infallible. If the wire nut is too big, use a smaller one. They'll hold. And in either case, they are susceptible to water in that location. But at least with the wire separately covered and taped and the breaker off, you will be safer.

    If you still want twists, cut a small length of wire and twist with the single end.

    Glad you resolved your HVAC issue, though.

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