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Yeah I was checking black/white, and red/light blue.
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Oct 1, 2016 00:24
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borkencode posted:Yeah I was checking black/white, and red/light blue. Yup, transformer's dead. Any 30-45VA 24V transformer ought to work (1.5A-2A or so)
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Oct 1, 2016 06:03
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Hey hvac thread, quick sanity check before I crawl under the house. Air handler blower fan is behaving as if it has a bad connection...starts up fine but during operation I can hear it cutting out and slowing down intermittently. No dimming lights in the house or anything to indicate poor service voltage, condenser hums along just fine. Assuming I have a bad connection somewhere...It also has a time delay relay in the handler that holds the blower fan on for about 30 sec after the tstst is satisfied, could that be the culprit? I'll start at the breaker panel first...any other ideas before I head into the hole? angryrobots fucked around with this message at 16:02 on Oct 15, 2016 |
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Oct 15, 2016 15:59
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Double post wtf
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Oct 15, 2016 16:01
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Check the connections at the thermostat first, and also replace the batteries, if it needs them.
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Oct 15, 2016 16:03
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Good idea, worth a shot but no dice. Still misbehaving.
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Oct 15, 2016 16:56
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angryrobots posted:Good idea, worth a shot but no dice. Still misbehaving. Check that the relay or contactor is staying pulled in, and if its getting a steady 24v. Ran into a bad transformer last week that was causing a similar problem. Check all electrical connections while you are in there as well.
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Oct 16, 2016 04:27
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Will do, whatever is going on actually failed open during operation earlier, so I turned it off. Hopefully it stays broken so it's easy to find tomorrow.
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Oct 16, 2016 04:58
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Well I found the problem at hand: Which was easily repaired, but uncovered the larger issue that my condensate pump did not survive the heavy rain from hurricane Matthew last week, and besides going inop the built in float switch was not working to break 24v to the condenser. I suppose the swelling groundwater combined with no power worked together to soak it without giving it the chance to bail itself out. Removed all that crap and got it back going for now draining on the ground, will install new pump tomorrow along with a new p trap with the goal of raising it up as much as possible. Long term what I really need is to rip out the split system and install a package unit with new ductwork hugging the joists. For now try to patch this bullshit until a later date.
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Oct 16, 2016 19:33
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It acted up again  So I pulled the tstat and measured at 28v. Jumped out the fan terminal, fan started to run and almost immediately kicked out, I removed the jumper but the time delay (built into air handler controls) tried to keep it going, I could hear something humming even though fan was not spinning. Voltage still holding at 28v at the tstat even during the failure so I think transformer is ok. Acts up even after tstat stops calling so I don't think it's in the tstat circuit. I guess tomorrow when I crawl my rear end back under there with the new pump I'll dig into it some more, but I'm guessing either the fan relay or time delay board (if so equipped, didn't see one) is toast.
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Oct 17, 2016 01:59
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Kind of an echo chamber, but here's where I'm at. Checked all connections again, looked at wiring diagram and realized that I have a Carrier air handler that has electronic controls built into the blower. Great. I double checked that it's harness was plugged in and ohmed out all the pins to eliminate a wiring problem. Moved the speed control from medium to high just to say I changed something. Buttoned up and turned on fan at tstat. Started, then kicked out and started humming sound. At this point I'm pretty annoyed so I just let it sit there humming, and angrily searched Google for an answer. I quickly found that these ECM blowers are a point of consternation for many, with solutions varying from the official >$1000 complete unit from carrier, a $234 ECM (mine is the newer x13 model), or a generic regular motor plus a contactor. At this time, the fan suddenly kicked on and held normal speed. I let it hold for about 5 minutes then kicked the a/c on and turned it way down. Pulled the house from almost 80 to 72, then shut it down. Let it sit for a few minutes, then kicked the fan on...It bucked a couple times then came up to speed and held. Well it's certainly not "fixed" but if I can run it while supervising (don't want to freeze the evap coil if it decides to stop working), that will buy me a couple days to figure something out. Clearly I prefer the simple solution if I can find the right standard motor to fit.
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Oct 18, 2016 04:34
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 Yeah, this is not a busy thread and repair via forums post is not a good way to troubleshoot anything. What you have is a very common failure mode for those x13 motors. The encapsulation for the electronics on the back of the motor was defective, and eventually moisture makes the control board inside go apeshit. Your options are as you say a 240$ replacement motor controller, or retrofit a psc multi speed google gives info on both.
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Oct 18, 2016 04:56
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My family's business is HVAC for high end clients in South Florida. I really regret not being able to talk about all the insane jobs we have done. I can say two things though. We are able to install air conditioning in your outdoor movie theater but we don't service smoke machines of any kind.
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Oct 18, 2016 08:20
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MRC48B posted:
Anyhow I ordered the module, hopefully that gets me back going for a while.
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Oct 18, 2016 12:18
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Yeah, I kinda stopped paying attention to this thread after nobody posted in it for like a month. Oops. But anyways, yeah, ECM units are notorious for failing in fun and expensive ways. They are a cool concept kind hamstrung by cheaping out on build quality. Trast posted:My family's business is HVAC for high end clients in South Florida. I really regret not being able to talk about all the insane jobs we have done. This sounds interesting. Commercial or residential?
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Oct 18, 2016 19:42
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All residential.
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Oct 19, 2016 05:09
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Question about furnace filters. I ordered these two Filtrete filters online, but they arrived smashed up (thanks, UPS!). The retailer's sending me two new replacements, but is there any harm in straightening out these ones and using them, any way?  \/ Thanks! I'll go ahead and fix 'em for use, then. melon cat fucked around with this message at 02:49 on Oct 21, 2016 |
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Oct 21, 2016 01:48
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Nah. Filters get mangled all the time. Just get them relatively straight and you'll be fine
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Oct 21, 2016 01:56
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Well ac is kicking again, condensate pump is pumping. About to drop 10k on a new roof, hopefully I can keep patching this horribly installed system for a year or two until I can afford a new package unit and new ductwork. Edit: also is there any rule of thumb, or back of napkin math or whatever (that doesn't involve me crawling around measuring ductwork) to figure what speed setting I should select on the ECM? It came from the factory at 'medium' and seemed to work well, so I put it back there. angryrobots fucked around with this message at 03:26 on Oct 21, 2016 |
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Oct 21, 2016 02:59
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So... lead up to summer here down under... is there any benefit of me crawling into my roof cavity and attacking the spaghetti monster thats up there to try and get into the evaporator housing to clean the fins off before summer really kicks on? Systems an LG ducted reverse cycle, bout 18 months old, but this house is in a new, still being built housing estate (so dusty as poo poo) and has a wood fire, two cats and the return air pickup is in the living room area with said wood fire and kitchen in it. Return duct has a filter on it that gets cleaned once a month.
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Oct 21, 2016 12:06
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It'd probably be worth it. If nothing else just to be sure. Btw, get rid of that washable filter, they don't really catch poo poo. Get yourself some pleated filters
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Oct 21, 2016 14:23
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Fellow HVAC goons I have a question. What software do you use for you companies? We're currently having nightmare issues with WINTAC and are looking for alternatives.
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Oct 21, 2016 18:40
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I asked this in another thread, but definitely want to know you HVAC pro's view on it. I recently heard that a lot house fires are caused by crappy/cheap bathroom ventilation motors. Is this true? I'm just asking because pretty much everything in our new suburban build is flimsy and cheap, and if there's even a slight possibility that the cheapest ventilation units were used, I really don't mind replacing them for safety considerations.
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Oct 23, 2016 23:37
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Never heard of it before. Most fan motors should have a thermal cutout to prevent this. Cleaning the motor housing every few years would go a long way I think.
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Oct 23, 2016 23:46
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Is there such a thing as a box that does humidification or dehumidification as-needed, like some sort of humidity management unit? Or do I really need to attach separate humidifiers and dehumidifiers to the ducts?
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Nov 26, 2016 22:49
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melon cat posted:I asked this in another thread, but definitely want to know you HVAC pro's view on it. I recently heard that a lot house fires are caused by crappy/cheap bathroom ventilation motors. Is this true? I'm just asking because pretty much everything in our new suburban build is flimsy and cheap, and if there's even a slight possibility that the cheapest ventilation units were used, I really don't mind replacing them for safety considerations. As a firefighter/fire marshal for decades.........I can't remember a single time this has ever been a cause of an actual real fire (i.e. at least a "room and contents"). Sure, smells and bells because the fan burnt up, but electrical devices like that are designed to not have enough fire load in them to start wood studs and other things around them on fire before they run out of energy. And then you have.....you know....breakers to turn off the power automatically. I'm not saying it's never happened. I'm sure it has. But in my experience.........cheap bathroom fans are just annoying because they are noisy. Not "burn your house down" dangerous.
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Nov 26, 2016 23:33
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Alereon posted:Is there such a thing as a box that does humidification or dehumidification as-needed, like some sort of humidity management unit? Or do I really need to attach separate humidifiers and dehumidifiers to the ducts? Generally, your air conditioner should be your dehumidifier. That's why it has a condensate pump to move the water outside. If you did have both, it would require a humidistat for each and some (not that complicated) additional wiring to make sure they weren't working against each other.
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Nov 27, 2016 03:02
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zharmad posted:Generally, your air conditioner should be your dehumidifier. That's why it has a condensate pump to move the water outside. If you did have both, it would require a humidistat for each and some (not that complicated) additional wiring to make sure they weren't working against each other.
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Nov 27, 2016 03:29
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Most people who require accurate humidity control in both directions are industry (printing, textiles, some plastics) or scientific customers (labs), and they run large air handlers or rooftop units with specific equipment setup for each, and a building automation system to manage it. The easiest and least expensive solution for you, John-Zoidberg-Homeowner, is probably gonna be the separate units. I have not seen combination units available residentially.
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Nov 27, 2016 05:19
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Alereon posted:I was looking at a dehumidifier because we have cool, humid days where I can't really turn the AC on (or can't turn it any lower) to reduce humidity while maintaining an acceptable temperature. We also have some very dry days in the winter, hence considering the humidifier. Installing both seems like an inelegant solution, that's why I was wondering if there were any boxes that would just monitor the humidity and keep it within a set normal range. Is your house still humid when your AC is running? It sounds like your AC might be dramatically oversized, so it's not able to dehumidify before it hits the target temperature.
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Nov 27, 2016 21:23
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devicenull posted:Is your house still humid when your AC is running? It sounds like your AC might be dramatically oversized, so it's not able to dehumidify before it hits the target temperature.
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Nov 27, 2016 21:44
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You can get little portable dehumidifiers with wither a tank you empty periodically or attach a hose to a drain. I think you'd want to try one of those as a first step.
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Nov 28, 2016 00:47
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Alereon posted:If the AC runs humidity is controlled, so that's great during the warmer seasons, but there are days when it's both cool and humid and the AC never runs. I guess I will put some time into thinking about if both a dehumidifier and a humidifier can be practically installed and if it's worth the effort. Depending on how your ductwork is set up you can get dedicated humidifiers/dehumidifiers that are sized to hook directly to the 12x20 or whatever ducting. They do require control logic slightly more complicated that a cheapo humidistat, if only to keep them from fighting each other constantly. They aren't that cheap either, I was pricing a set out to do exactly what you're describing because gently caress using portable units, and it would add like $5k to my new house build to get it all wired up.
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Nov 28, 2016 20:47
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Re: dehumidifying on cold, damp days. What if you essentially forced defrost mode on the system? Ran the a/c with the backup heat at the same time, for a short period of time? Would that work, and what would be the most user friendly way to implement if so?
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Nov 30, 2016 23:06
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Here, have a chart:  The problem with running heat/cool or eheat/cool at the same time is 9 times out of 10 the systems are sized so the heat will completely overpower any cooling effect. Your average furnace puts out about 60,000 BTUs/Hour, and puts out 130-150f air. (That's measured right after the heat exchanger, you lose a bit due to ducting losses) Most homes have an AC system that will do 2 or 3 tons of refrigeration, which comes out to 36,000 btus an hr. That's half. Under Ideal conditions. A return air temp of 130+ DEG is not ideal at all. Most residential systems are either: A (gas or oil) furnace, with an AC coil after (downstream in the airflow path). In most cases, the AC coil is right above the furnace heat exchanger tubes. Any moisture that condenses on the coil will get vaporized before it can make it to the drain once the furnace heats up. A heat pump with "Emergency heat", which is basically a series of electric heating elements (a big toaster) after the AC coil. Usually they're mounted right on the back side of the coil. This would work, except again the electric heat elements will drown out the cooling system, preventing it from dropping below the dew point of the incoming air. If you had a system that had components you could modulate, this might be workable. But you're trying to do this on the cheap, so buying a new furnace is out, and a way to modulate 10 kilowatts of eheat won't be cheap either. Residential systems do not have a "defrost mode" for the indoor coil, because they are not supposed to ice up. Heat pumps will have a "Defrost mode" for the outdoor coil, because that will frost up in low outdoor temperatures. What it is actually doing though, is just switching back to AC mode for a bit. TLDR: Buy a purpose-built dehumidifier. It will be more efficient, reliable, and cost you less in the long run. People (not me), with fancy degrees do a lot of math to make these systems work in a specific way, and they don't even always do that.
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Dec 1, 2016 04:10
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Thanks for the dehumidification brief. So I have a room in my shop that was an office/bathroom, that I wish to convert into a guest apartment. Currently it has an inop package unit, and the duct work for said unit takes up most of the roof space, which would make a very useful storage area/mezzanine. The room is 224 ft², is there any reason I shouldn't just rip all that crap out and install a 9000 btu mini split? There's a 22 seer Sharp complete install kit on eBay with line set and pre-charged unit for $817 shipped, and that seems like a great deal to me.
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Dec 5, 2016 20:54
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This is an awesome thread, thanks! I do have a weird sort of question - I recently bought an Ecobee3 thermostat thanks to a Black Friday sale and a killer rebate from Georgia power. The apartment complex I live in encourages us to get power-saving thermostats, but now I've learned that they did not wire in a common coming from the A/C unit control board. Normally this would be fixed by the included Power Extender Kit that Ecobee sent in with the thermostat, but the utility closet is locked and the maintenance team literally told me "you're welcome to install a thermostat, but you're not allowed in the utility closet". When I told them I can't install a smart thermostat without a common line, the guy got confused amd just told me "it will work". Yeah, ok - really hard for you guys to unlock a loving door, or just as easily run a 5-wire setup for the 4 foot run from the HVAC unit to the thermostat that's on the other side of the drywall. No, we'll give our folks lovely knock-off digital thermostats that eat loving batteries like obese kids in a Doritos factory. Gah, I digress. Anyways - is there any way this thing may work without the common wire or am I just hosed? Need to send it back soon otherwise.
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Dec 6, 2016 21:14
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I would suggest bribery. Most apartment maintenance guys don't get paid much. Or if there is an HVAC contractor who does your common area equipment, ask/bribe them to hook up the common wire for the unit.
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Dec 6, 2016 23:12
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MRC48B posted:I would suggest bribery. Most apartment maintenance guys don't get paid much. Or if there is an HVAC contractor who does your common area equipment, ask/bribe them to hook up the common wire for the unit. Hooking up the wire isn't a problem, I could honestly probably fish some fishing line through the existing hole and stretch some 20 gauge wire in there in a matter of 15 minutes. Getting access to the drat HVAC unit to connect it is the big problem, as they literally have it behind a locked door. I'm actually kind of hoping that the water heater (also in there) explodes/develops a major leak while I'm here, so I can call the company and watch as my neighbors get their ceilings and personal poo poo ruined as the apartment complex scrambles to find a maintenance guy with a key.  Hell, I'd bribe them all day if I could find one of the guys around here, but they're rarely, if ever, to be found.
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Dec 7, 2016 01:49
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Ripoff posted:Hooking up the wire isn't a problem, I could honestly probably fish some fishing line through the existing hole and stretch some 20 gauge wire in there in a matter of 15 minutes. Getting access to the drat HVAC unit to connect it is the big problem, as they literally have it behind a locked door. What kind of lock? Bumping some locks isn't exactly hard....
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Dec 7, 2016 01:54
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