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What's this stuff attempting to seal where the various pipes enter my HVAC system? Plumber's putty? While completely fine in some places, it's not forming a complete seal in others, so I'm looking to replace it. Also, am I right in thinking the AC condensate drain does not disconnect? It's open so I should be able to clean it from there. I find it odd since it seems like the furnace below does.   Bonus question! Why is there a screw coming out of the duct work above my furnace!? 
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Aug 22, 2023 00:28
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| # ? May 18, 2024 02:37 |
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1: yes, plumbers putty. 2: depends if the jerk who installed it glued it or not. I prefer not glued, for disassembly for cleaning. the drain is at zero pressure, so it shouldn't leak even without glue. ymmv. 3: its attaching the air conditioning coil assembly to the sheet metal of the duct.
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Aug 22, 2023 00:47
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Thanks! I'll give the pipes the yank test when I'm ready to clean.
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Aug 22, 2023 01:44
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MRC48B posted:I prefer not glued, for disassembly for cleaning. the drain is at zero pressure, so it shouldn't leak even without glue. ymmv. Where I live gluing pipes of any kind isn't a thing for some reason. Anything under pressure used to be metal, now PEM or PEX is common and you can't glue that poo poo anyways. PVC is standard for drains though, the parts look like this:  That little rubber seal is enough to stop the zero pressure poop water from leaking, can still be disassembled for cleaning. A plumber's trick I've learned is to use a little soap as lube, makes the parts slide together easier.
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Aug 22, 2023 06:00
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I have a largeish room in my basement, like 19x19. It has 3 supply vents in it, but only 1 return (6 inch round). Generally the door to this room is kept open and it is not a problem, but I would like to be able to close it up when watching a movie for example to help keep sound in. I am worried that the return will not be adequate, especially is I have a bunch of people in there. I am wondering about the usefulness and appropriateness of adding an inline fan to the return. Something like this: https://shorturl.at/alnOR. Is this a good idea? If so, are there recommended products? If not, any other suggestions? adding an additional return is beyond the scope here given the layout.
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Aug 22, 2023 15:46
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emocrat posted:Is this a good idea? No. You can't increase your return capacity with a fan, you have to increase your return capacity with more return capacity. A line fan like that is likely going to throw off any existing air balance you have in your house in all kinds of infuriating ways.
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Aug 22, 2023 15:51
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Hijacking the question a bit as I have a similar problem with my movie room (heat just gets trapped in there and refuses to get pulled out). Would adding a return be the best/only option in this case? A previous owner seems to have added a small vent to the neighboring room at ground level (it’s basically just a hole in the wall), presumably in the hopes that heat will just magically waft out through there on its own, but obviously that does nothing… could I just add a fan of some sort there to that vent to pump the air into the next room? It’s a large, open game room and the fan would only be running if I’m watching a movie or something, so I don’t really care about that room getting hot.
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Aug 22, 2023 19:12
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Motronic posted:No. Ok, glad I asked. Thanks!
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Aug 22, 2023 22:08
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Is it better (as far as unit health goes) to run a central AC unit more frequently or for longer periods of time? Got some real hot days coming up, and I'm seeing mixed answers about this. We need it to be cold at night to sleep well, and for these hot days I'm not sure if it's better to try and keep a lower temperature throughout the day (more frequent runs of a half hour or so) or keep it a little higher during the day but then cool it off in a long burst (a few hours straight) at night.
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Aug 22, 2023 23:24
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Longer periods of time is better. startup uses energy that is not converted into useful work, and compressors require a minute or two to really start cooling. every start/stop cycle adds wear to the bearings. the kicker is most resi systems are "single speed", so longer run times means more temperature fluctuation. this leads to discomfort. if you have an advanced stat like a nest or whatever, set the differential or maintenance band or whatever its called as high as you can tolerate. shorter cycles also do less de humidification, which may or may not be a problem for you depending if you live in desert or swamp. daytime setbacks are good energy savers to a point, you get diminishing returns beyond 3-4 degrees. depends on system sizing.
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Aug 22, 2023 23:52
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MRC48B posted:Longer periods of time is better. Is the same true of mini-split systems? I’m in Connecticut where it goes down to 60 at night and up to 85 during the day and we try to keep the house around 75 during the warmest part of the day. My mini splits never seem to stop running like a conventional AC unit. Like it’s always blowing something. But I’ve been told minisplits it’s even more important to leave them in because their recovery time is horrible.
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Aug 23, 2023 00:03
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the basic physics doesn't change. your controlled zone will gain or lose heat at a lower rate if the temperature delta between inside and outside is smaller* assuming your structures insulation isn't total garbage, setbacks are still effective it in terms of energy savings, the payback is just smaller, because the efficiency is inherently higher. sizing is different for minisplits so i have been told a reduced setback of 2-3f is recommended. *does not apply to solar or other direct radiation
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Aug 23, 2023 02:34
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Asked for a bid on a fully variable heat pump with giant media filter and humidifier plus vent unfuckery yesterday. Having a 2nd person come out tomorrow. Please pray for my bank account. They spit balled 5tons for 2250 Sq ft, 2 story, all double glazed windows, and well insulated. House currently has a 4ton which seems to do the job. He said it "should" be 4.5t for a single speed based on some calucator the state has for our zone, size, and stories?
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Aug 23, 2023 02:39
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Where do you live? There’s also a thing called a Manual J, which is a way to estimate the amount of heating/cooling your building needs. If you’re really unsure of the size you need, ask if they will do a manual j calculation. It’s not always done, but if a guy is telling you to upsize your unit, I’d be really sure that it needs to be done.
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Aug 23, 2023 03:01
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The hot part of LA. I'll talk to the person tomorrow and start comparing / contrasting. I have a feeling none of them will want to do manual j.
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Aug 23, 2023 03:03
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there is zero downside for a contractor for over sizing variable speed units (until you get into the really big units that need a crane) bigger unit, more money, higher profit margin. install costs are basically the same. variable speed units won't short cycle and wont have humidity control problems. plus it saves them if they under estimated heat load because they miss the fact that a wall is missing insulation or the windows leak like hell or something.
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Aug 23, 2023 03:08
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Yeah that's what I was thinking. The windows are all milgard and at a glance are installed correctly. I'm going to have an efficiency audit done before I commit to anything. Thanks for the tips, that sort of vibes with what I was imagining re: sizing. Half of the roof is unshaded south facing but I'm also going to cover it in solar to convert that radiation into cooling.
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Aug 23, 2023 03:37
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Looking for new unit advice. We have a really interesting situation - We live in a church that got turned into a house, and a consequence of this means 'weird poo poo'. In the case of our HVAC system, that means that we don't really have single, central air, but that we have several compressors / heat exchangers running to a few strategic points through the house. This actually works very well in keeping the place cool. However, our entire set of systems is all from 1989 - they are old, inefficient, and starting to show signs of their end days. We are looking at getting a new set of systems to replace them. Looking around, it seems like all the modern equipment is running on Puron as a coolant, but it's being phased down in favor of R-32, R454B and some others. I'm trying to understand if I can get a 'next gen' set of compressors that uses these more modern coolants. They seem to still be very rare at the moment, but I might just not be able to ask the right questions. I'd also like to understand if I can keep my heat exchanges. Right now the system is 2x 2.5t units, and a single 4 ton unit with what I assume are matching heat exchanges. If I replace the compressors, can I keep those exchanges? Likewise, can I keep the coolant lines that are already ran? Finally, I'm looking for a ballpark cost estimate. So, question laid out more easily: • Can I get a set of R-32, R-454 units yet, or am I stuck on Puron? • Can I reuse my existing heat exchangers and just replace the compressors? • Can I keep the existing coolant lines? • What's going to be the (really rough) cost of replacing 2x 2.5t units and a single 4 ton unit (Region: rural midwest)? (We do have a couple sales people coming out in a week to answer these same questions, but I'm always suspicious of sales people overselling / making poo poo up.)
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Aug 23, 2023 17:47
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Follow-up on my earlier questions in-which I continue to overthink things. Is there any reason I shouldn't look to seal these unused knock-outs and gaps (more on other side)? I'm thinking it would minimize dust. Slap some HVAC tape or buy some plugs.  I should seal this gap between filter box between the return and the furnace, right? Air is skipping the filter otherwise. 
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Aug 25, 2023 22:21
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Those should all absolutely be sealed. All you need is a roll of aluminum tape. Don't overthink it. Edit: It's also not the end of the world if they aren't, so don't go running out with your hair on fire to get this done either.
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Aug 25, 2023 22:27
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If my system is still overheating after a new capacitor and the pipes aren't freezing, it's probably the fan motor right? It'll kick on intermittently but overheats and shuts down, the compressor tries to start it back, but it won't run again until it's cooled a bit.
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Aug 25, 2023 22:39
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Bottom Liner posted:If my system is still overheating after a new capacitor and the pipes aren't freezing, it's probably the fan motor right? It'll kick on intermittently but overheats and shuts down, the compressor tries to start it back, but it won't run again until it's cooled a bit. Looking back on your post history yeah, sounds like a fan motor. Did I ask you if you tried to spin it by "hand" (i.e. stick a screwdriver in there and try to spin the blades when it's off) to see if it spins freely, can freewheel at all or just feels gritty? If you catch it when it's just stopped spinning/hot and it's basically locked up you can confidently say you've diagnosed this issue. But I bet it would feel bad even when cooled off if this is your problem. The other thing that gets done to test things like this is throwing an amp clamp around the fan motor feed, but I'm going to assume you don't have that kind of meter laying around. If for some reason you do....use it. The fan will have it's amp draw on a sticker. If you're at o r exceeding that it's a really great confirmation that it's bad providing you have also checked first that you have proper supply voltage.
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Aug 25, 2023 22:45
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New fan motor in and my house is nice and cool. Was a much easier process than I thought. Cleaned evap coils as well, so much better.
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Aug 27, 2023 02:18
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Hell yeah! Awesome job!
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Aug 27, 2023 02:30
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Well spoke too loving soon. Overheated again, motor and fan guard hot to touch. It ran much longer than the old motor but still hit shutoff way before reaching the set temp (74, nothing crazy) and compressor keeps trying to turn it on. Sprayed some water and got steam. What should be the next step? I just adjusted fan height and raised it a bit after letting it cool off, getting more air flow now. Coolant should be good as nothing is freezing over. At a total loss here.
Bottom Liner fucked around with this message at 03:07 on Aug 27, 2023 |
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Aug 27, 2023 02:58
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Okay so have you taken a multimeter to any of the wires to try and figure out if your voltage or amperages are correct? I would specifically check the voltage to the compressor and the fan, and then check how many amps both are pulling. Compare the numbers you get to what the rating plate on the fan/compressor say they should be. I think at this point it may be your compressor having issues, and it's not an issue with the fan. You may be misinterpreting a symptom as the cause.
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Aug 27, 2023 03:22
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I checked the 3 motor wires before and after swapping the fan motor and they all matched, should I check others? Motor is all same specs as well. Compressor has no problem kicking the motor on as soon as I hit the switch when the unit is cool. No vibrations or noises, air from vents is cool and no noticeable condensation leaks around condenser.
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Aug 27, 2023 03:28
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At this point I would be checking the voltages and current draw of the compressor as well, and seeing if the sustained current draw is more than what it's rated for. Too much current on either motor means they're struggling and will generate excess heat.
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Aug 27, 2023 03:51
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Bottom Liner posted:Well spoke too loving soon. Overheated again, motor and fan guard hot to touch. It ran much longer than the old motor but still hit shutoff way before reaching the set temp (74, nothing crazy) and compressor keeps trying to turn it on. Did you do any of the diagnostics I suggested above, even the one where you just try to spin the fan to sew how it feels or did you just slap a fan motor in?
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Aug 27, 2023 15:21
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Yeah fan spins free on both old and new motor. I also tried giving it a push to help start when the compressor was running and it was overheated, but that did nothing.
Bottom Liner fucked around with this message at 17:02 on Aug 27, 2023 |
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Aug 27, 2023 16:32
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Ok so just sanity checking on a few questios. I want to clean my blower because:  I know how to remove the circuit board, but, somewhat embarrassingly, the hose is giving me trouble. This is supposed to come off, right?  Drink beer and pull harder? Yes I'm releasing the clamp thingies as I pull, lol.
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Aug 27, 2023 16:59
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Jenkl posted:Ok so just sanity checking on a few questios. You may need to get a pick or something in between the hose and the fitting... they can become pretty firmly attached over time.
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Aug 27, 2023 17:38
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Bottom Liner posted:Yeah fan spins free on both old and new motor. I also tried giving it a push to help start when the compressor was running and it was overheated, but that did nothing. Yeah, so that very likely means that the fan was fine. I would not have changed it without further diagnosis (amp clamp). It's almost a certainty your compressor is bad. But it needs to be diagnosed, not parts cannoned. You're at the part where it's beyond the tools you're going to have access to.
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Aug 27, 2023 18:28
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I accidentally left my house's AC on way too low (68 lol) overnight last week, and in the morning there was ice on the refrigerant line and around the plumbers putty where the line entered the air handler. I turned off the air conditioner and let the blower run to defrost things, and I was getting a ton of water leaking out down into the furnace as ice melted. I realized I had accidentally left my basement dehumidifier off for a few weeks so that certainly didn't help, but I'm not sure how much of an issue this is--could this just have been ice forming where it wouldn't normally form (esp. with the extra humidity in the air), or might I have a problem with the drip pan rusting out, or some of the plastic drain line fittings getting damaged from ice? All my drain lines run to a pump, which I tested and is working fine from the last time I cleaned it. So either a drain line was blocked by ice, the drip pan is leaking or a plumbing fitting is damaged and leaking, right? I can remove the filter from the whole-house humidifier unit (since if you remove the wick element there's just a hole into the air handler) and take a look inside, but I'm not sure what to be looking for. Any thoughts?
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Aug 31, 2023 00:01
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That's not even close to "way too low" for properly functioning comfort AC. You either have no problem at all other than a really humid space (why wasn't the AC dehumidifying the space it is in?) or you have low refrigerant and the coil was freezing.
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Aug 31, 2023 00:09
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Motronic posted:That's not even close to "way too low" for properly functioning comfort AC. crap
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Aug 31, 2023 00:22
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There are certain circumstances where 68f setpoint could be a problem*, but they are rare. You're probably low. * Severe return air short circuiting problems, where the supply air basically goes right back to the return, so your return temp is more like 60 or less. A ducting design issue. Or unit is severely oversized for the space.
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Aug 31, 2023 02:24
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I forgot to add, the temperature outside also dropped to 55 during the night, if that makes any difference. But a problem with the refrigerant is definitely possible. A new compressor was installed 3.5 years ago while I was making arrangements to buy the house, but it was installed in late winter/early spring when it was still cold. I didn’t notice any issues in the first summer, but during the second I noticed the AC was running too long and not getting that cold. I called a company to come look and they sad the pressures were all over the place and that I needed to flush and recharge the system because there was moisture present. Instead I tracked down the original installer and someone came to look for like 5 minutes and the either bled refrigerant or added some (i forget). That seemed to adequately resolve the issue and it cost me $0 so I haven’t worried about it again until now. Maybe I’ll call them back.
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Aug 31, 2023 03:34
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I've gotten 3 quotes so far, they are all within spitting distance of each other on price but one guy actually took the time to measure things, talked to how he's going to unfuck some duct work then wrote it on the bid, all direct employees, etc. When I asked him to itemize out the optional stuff there was no hesitation just asked for a day to turn it around. Probably going with him unless y'all tell me something horrifying about Allied Manufacturing Armstrong HVAC units. He also included all make/model/warranty/consumable costs right on the sheet. Good vibes. One big question is thermostat. He proposed a ecobee system, but I am worried it's not going to give me the full magic of infinite variability of this fancy rear end heat pump I'm buying. Am I going to be stuck with like 5 fixed "stages" if I go with this? The documents seem to infer that but I can't find anything definitive. I have posed this question directly to him as well in email, this is "trust but verify" so I can resolve it before it's an issue. Allied Mfg 5 Ton 19 SEER2 Variable Heatpump MFG #: 4SHP22LX160P Air Handler Variable Speed MFG #: BCE7S60MA4X50 **AHRI #211727077
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Sep 1, 2023 22:09
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| # ? May 18, 2024 02:37 |
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I have an Ecobee on a fully variable system and it just calls for heat/cool/fan as with a single-stage; the air handler and outside unit decide staging on their own. I'd say I'm happy with it but I've also had two years in a row of "this shouldn't ever happen" compressor failures, but the first of those was on a Nest. If for no other reason, I'll keep shilling for Ecobee because of beestat.io.
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Sep 1, 2023 23:42
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