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There's a couple things it could be 1. Is you fan set to auto? If it's on the ON setting it'll run 24/7. Auto only makes it run when the system is calling. 2. Could be the relay is stuck closed. 3. Tstat could be bad, and constantly calling for it. Or it could just be wired wrong. Somebody might have wired it straight in.
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Apr 14, 2017 18:15
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I've got a 3 story with finished basement new construction townhouse corner unit - 1900 sq ft of total living space and was built last year. The HVAC system is new, with a 3-ton condenser. It seems to struggle to keep the house cool, consumes a lot of electricity and runs more than it should, so I'm trying to narrow down reasons why this might be. The two return trunks are run from the basement where the air handler is through two 16 inch 2x4 stud bays in the exterior wall. More on that later. One of the trunks stops in the first-floor living room where the grille is, the other goes up two stories to the third-floor hallway. (Here's a photo of the return trunks before they were drywalled - https://i.imgur.com/6fguakM.jpg) You can see how the trunk on the right terminates at the ceiling, and the left one goes into the ceiling and up to the third floor. When they installed the return grille for the first floor (pictured here - https://i.imgur.com/aobG3Ho.jpg) they for whatever reason cut the drywall about 6 inches into the third floor return trunk on the left. I'm wondering if this is a design flaw, I can't understand why you would want to partially open up the third-floor trunk on the first floor, seems like it would just rob pressure potential from the third floor return and make the system less efficient. Another thing I realized is that the return trunks are running up the entire side of the house, and since they take up two entire stud bays, there is no insulation. The exterior wall is clad in metal siding, and it is a southern facing wall, so I'm assuming these trunks are taking on a decent amount of heat from the siding and bringing it into the system, reducing efficiency. Lastly I noticed they ran Romex through the return trunks, can see that in the first link. Is that kosher? EDIT: I am a moron, these are returns and not supply. Corrected post. EDIT 2: It took from 3PM until 10PM to get from 76 to 73. BusinessWallet fucked around with this message at 03:01 on May 20, 2017 |
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May 19, 2017 19:13
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Without knowing a few more factors, this is gonna be a pretty general diagnosis, but, let's start with what we have. First of all, at 1900sqft, a 3 ton sounds like it might be somewhat undersized. But, I'd need some more info on the layout and whatnot to know for sure. Also, one unit, for a three-story house definitely can cause some problems. The whole concept of A/C is that it basically sucks the heat out of a room, and that is mostly achieved by exchanging a certain amount of air out of each room, which is why duct sizing is important, for proper CFMs. So if you're trying to force air all the way from the first floor or basement all the way up, and there's no change in duct size, that can certainly cause issues. Some of this can be mitigated if they installed dampers or booster fans in the system. Dampers are supposed to be standard for each supply register run, but they don't always adjust them properly. As far as the return openings go, if I'm understanding you correctly they cut into the 3rd floor return....for no reason? It's sounds like something they accidentally did I assuming you're also checked for the other basics? Like the filter is clogged or the evap coil isn't all plugged up with drywall dust or something from construction? BusinessWallet posted:Another thing I realized is that the return trunks are running up the entire side of the house, and since they take up two entire stud bays, there is no insulation. The exterior wall is clad in metal siding, and it is a southern facing wall, so I'm assuming these trunks are taking on a decent amount of heat from the siding and bringing it into the system, reducing efficiency. BusinessWallet posted:Lastly I noticed they ran Romex through the return trunks, can see that in the first link. Is that kosher? Absolutely not. You're not supposed to have anything in the ducts except for air.
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May 20, 2017 03:37
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OK folks, crossposting this from GarageJournal. I've been eyeing the Mr Cool DIY series minisplit units for several years, and have yet to hear any real horror stories. I've got Fujitsu units going into my main house (single outdoor compressor and 3 interior heads), but don't really want to spend $4000 (quoted) on a Fuji unit for the apartment over my garage. It's 20x24, fully insulated, angled 13' ceilings, a bunch of large windows/skylights, and I'm on Cape Cod, MA. I figure an 18K unit will cover things nicely. I know about the non-adjustable lineset length, it'll actually work for me because the apartment is on the second floor, and I'll need ~25' of lineset to reach the mounting location. I have an existing outdoor generator hookup receptacle that I'll be switching over to a conduit box and run that over to the location, it's on a 30A breaker. I've got the conduit and fittings to run to the disconnect already. Here's the current list, all coming from HomeDepot for 2% cashback from Chase Rewards and local returns: 1. 18K Mr Cool Unit, 16SEER (yeah, I know, but it's my tenant and he pays separate utilities and has electric baseboard and a window unit right now) 2. Wall Mount Bracket (Any brand better/worse on these? I'm looking at the Rectorseal because it has a crossbar that can cover 2 studs with the mounting arms that can slide around to adjust to the compressor, rather than the cheaper ones that just have 2 angled arms that you bolt to the wall) 3. 3x 8' Rectorseal Fortress 3.5" Lineset cover pieces, 3x couplers, 2x 90° elbows, wall inlet, and endcap 4. 6' 3/4" 10-3 NM Whip 5. GE Fused AC Disconnect and 30A fuses (Is it worth getting the one with the GFCI receptacle mounted inside?) Anything else? This is over bare dirt, so I'll run a drain line down and terminate it 6" or so above the dirt. Do I need a condensate pump? Drain pan heater? Just buy a Mr Slim MSZ-GL18 for $2200 and pay one of you fine fucks to vacuum/charge it?
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May 24, 2017 05:24
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BusinessWallet posted:Another thing I realized is that the return trunks are running up the entire side of the house, and since they take up two entire stud bays, there is no insulation. The exterior wall is clad in metal siding, and it is a southern facing wall, so I'm assuming these trunks are taking on a decent amount of heat from the siding and bringing it into the system, reducing efficiency. What big city/state capital are you closest to, for a rough latitude and elevation adjustment? Without knowing what kind of humidity and design temps you're living within, there's only so much that can be spitballed.
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May 31, 2017 02:05
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Does anyone have any experience with geothermal installations? We just bought a new place in San Antonio, TX. It's a 4/3, 3350 sq ft with two stories. Both the down and up A/C units, 2 water heaters and pool heater are all pretty old and will likely need to be replaced during our tenure. From what I've read, geo is usually 2x - 3x what a normal A/C replacement would be, but since I have to do everything, it might make sense? Anyone have experience with doing installs on an existing property rather than a new build? Pricing? How badly do they wreck your yard? Etc.
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May 31, 2017 03:48
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I'd be really interested in observing it because I have no experience however, I'd assume it'd at minimum be the equivalent of drilling two wells, which means that poo poo will get tore up. Also have you looked at how much work would be involved in running fluid-filled pipes around your home, in order to condition the air? I've seen a couple/few geothermal systems in place and the piping is pretty substantial - I dunno if I'd even consider trying to retrofit it into a small/medium home unless you want to tear a LOT of stuff up, I'd assume..? coyo7e fucked around with this message at 17:32 on May 31, 2017 |
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May 31, 2017 17:29
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coyo7e posted:I'd be really interested in observing it because I have no experience however, I'd assume it'd at minimum be the equivalent of drilling two wells, which means that poo poo will get tore up. Err, I thought geothermal usually involves a water->air heat exchanger. So it's basically the same as a normal forced air heater, as far as heating/cooling the house goes.
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May 31, 2017 23:29
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Yeah I have no idea what he's talking about there. Geothermal is just a regular Forced air AC unit, just instead of exchaging the heat of the refrigerant with the air or water, it's gylcol, which is in turn exchanging heat with the ground. Running chilled water all around a room sounds hilariously inefficient.
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Jun 1, 2017 01:52
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I've seen on This Old House where the geothermal loop was also tied to in-floor whole house heating, and the water heater. They had one of those utility rooms with tons of pumps and mixing valves and a framed single line diagram on the wall. Maybe that's the kind of integrated system he's talking about?
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Jun 1, 2017 13:00
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angryrobots posted:I've seen on This Old House where the geothermal loop was also tied to in-floor whole house heating, and the water heater. They had one of those utility rooms with tons of pumps and mixing valves and a framed single line diagram on the wall. Maybe that's the kind of integrated system he's talking about? I'll bet he's thinking of radiant heat in a large house/slab, with a ton of loops and valving/circulators to spread it out evenly.
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Jun 1, 2017 15:18
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coyo7e posted:What facing are the walls where these non-insulated ducts are running, located on? If they're Southern or Westward-facing then you could be picking up some serious heat gains from solar exposure. The wall is southwest facing. I live in Philly.
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Jun 1, 2017 17:19
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I got this back from a geothermal guy:quote:Retrofit: With the 5 series being a two speed fan and the 7 being a variable. The price includes drilling, pipe work, equipment and any other work necessary to adapt old duct system to the new unit. The system is an air exchanger system. I'm also having them look at replacing the water and pool heaters. We'll see how that works out. This is in San Antonio, TX if that matters. jarito fucked around with this message at 00:54 on Jun 2, 2017 |
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Jun 2, 2017 00:52
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Use the pool heater as the condenser for the A/C 
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Jun 2, 2017 01:11
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ExplodingSims posted:Use the pool heater as the condenser for the A/C Also for preheating your domestic hot water. The downside to this is water to water heat exchangers are expensive and not maintenance free.
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Jun 2, 2017 02:21
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ExplodingSims posted:Use the pool heater as the condenser for the A/C The cooling the house season and heating the pool season would have very little overlap in tx I'd think
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Jun 2, 2017 15:44
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So I came downstairs to find a lovely pond around my furnace/AC unit. I think it's been leaking slowly over a few days and it's just gotten big enough to notice. My instinct is to blame the sump pump, but is there anything else I should look for or am I better off not chasing a diagnosis and just letting an HVAC tech handle it?
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Jun 3, 2017 05:33
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There's a few things you can check. First of all see if the drainpan in the unit in full of slime, or if the drainline is plugged up either. Usually the P-trap will get snotted up. Just flush it out with water. It sounds like you have it draining into a condensate pump? If that's the case I'd also check to make sure that's pumping, and that the intake hasn't gotten slimed up or anything.
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Jun 3, 2017 06:25
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First I'd have to find a drain pan... Thanks for the tips. I'll stomp around it tomorrow when the light is better, but I think it's the pump. I can't actually look inside to see if it's working but it's not making any noise.
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Jun 3, 2017 08:29
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Qwijib0 posted:The cooling the house season and heating the pool season would have very little overlap in tx I'd think
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Jun 4, 2017 17:37
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coyo7e posted:to worry about checking the filtration etc in their home HVAC system. I cleaned my gf's filter and it had like a quarter inch of cat hair caught in it. Now the intake doesn't make this droning/screeching noise and the flow from the outlets is like 3x better.
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Jun 4, 2017 17:55
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Spookydonut posted:I cleaned my gf's filter and it had like a quarter inch of cat hair caught in it. Now the intake doesn't make this droning/screeching noise and the flow from the outlets is like 3x better. But I sold it for 70 bucks 4 weeks later when temps hit 80+ and after I chipped all the crap out of it and it didn't smell like cold dealth anymore 
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Jun 4, 2017 19:45
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We moved into a new house a few weeks ago and turned on the AC for the first time yesterday. The unit itself is old but it runs and cools slightly, keeping the temp at about 80 on the main floor but the basement is like a fridge. There's AC vents down there (for some goddamn reason) and I closed them but it didn't change anything. Is there something else I should be looking for?
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Jun 12, 2017 14:33
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See if there's any dampers on the main trunk going upstairs, or make sure it's not ripped open or otherwise restricted. Also make sure you have good airflow for the return from upstairs.
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Jun 12, 2017 15:49
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Welp, here we go. First triple head mini split install for me.  Line sets should be in on Thursday. Still need a disconnect and probably more liquid tite fittings....inventory is low right now. These are the whacky LG Art cools: 
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Jun 13, 2017 00:09
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Those mini splits get flared fittings right? You have me thinking seriously about installing one of those in my detached apartment, but I guess I'll have to get a tech out to terminate the lines and start up.
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Jun 13, 2017 02:22
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angryrobots posted:Those mini splits get flared fittings right? You have me thinking seriously about installing one of those in my detached apartment, but I guess I'll have to get a tech out to terminate the lines and start up. Yes, they are all flared lines. You should probably vac that poo poo down before letting the charge out of the compressor, and the charge weight is based on.....I think....25 foot line sets, so some adjustment will likely be necessary.
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Jun 13, 2017 02:35
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Charge is based on a MAX of 25ft. If you have less line, the unit compensates. More and you need to add. RTFM, it will tell you.
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Jun 13, 2017 03:11
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That's interesting. If you manage to fit the 25' line set without cutting it, is it factory flared on all ends? I'm assuming or thinking the mini splits use their own proprietary-ish line set that comes with the units? I have no issue with buying a vacuum pump, hell I could probably borrow one from somebody.
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Jun 13, 2017 04:53
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angryrobots posted:That's interesting. If you manage to fit the 25' line set without cutting it, is it factory flared on all ends? I'm assuming or thinking the mini splits use their own proprietary-ish line set that comes with the units? I have no issue with buying a vacuum pump, hell I could probably borrow one from somebody. You can buy pre-flared or not. I'm getting these: http://www.supplyhouse.com/JMF-406-50-12-144EZ-A-1-4-LL-x-3-8-SL-x-1-2-Mini-Split-Line-Set-w-Flare-Nuts-EZ-Pull-Insulation-EZ-IN-Wire-50-Ft Which have the electrical in them already, but you need to flare them on your own. Figured this was a better idea as I don't want to have to deal with excess linset, so I'd be re-flaring at least one side myself anyway. MRC48B posted:Charge is based on a MAX of 25ft. If you have less line, the unit compensates. More and you need to add. RTFM, it will tell you. Yeah, I haven't gotten that far and honestly didn't care to look since I'm just gonna do the bullwork and electrical and have a buddy who does this poo poo all day long come by to test/vac/start up/add more (I've got runs that will be about 20, 50 and 60 feet).
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Jun 13, 2017 18:50
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Motronic posted:Which have the electrical in them already, but you need to flare them on your own. Heh....2 of them just came in. They are pre-flared. I guess I'll see if they fit and if not I'll just take off excess at the compressor outside.
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Jun 13, 2017 20:46
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Got a question. My house is a 2 story cape cod so the upper floor is only 1/2 the sqft of the lower. I've been trying to get the upstairs AC unit to actually maintain 75* during the day. The problem seems to be a bonus room over the garage. The room has an (uninsulated) attic hatch, hot water heater and two (uninsulated) knee wall (R-13) doors. It's also about 1/3 the floor space of the upstairs and only has 2 supply vents. Attic has ventilation issues to compound things and sits around +40*F from ambient. I've insulated all the doors, as well as the hot pipes coming off the WH and the pressure relief pipe on the WH. The upstairs AC also seems to draw air in through the WH vent stack if one of the doors is closed. There is a door that closes off almost all of the upstairs except for one of the rooms, that room has 2 vents in it. That room is on the same AC unit as the rest of the AC and has no intake. The space under the door draws enough air to blow out a lighter. Completely not to scale drawing. I would add a 14x6 vent between the "Room outside zone" and "hot room" to help reduce how much pressure drop that section has when the hallway door is closed. Is this a terrible idea? http://imgur.com/a/nab9e
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Jul 8, 2017 22:16
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Where is the upstairs thermostat?
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Jul 8, 2017 22:53
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Let me tell you about how much fun I'm having so far........ Sill plate goes into the block, the PCB to dry contact box supplied cables are so short I don't even know how I'm gonna make it work at this point. I'm giving up and cracking a beer. This will wait until tomorrow.
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Jul 8, 2017 23:31
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Lol. Post all your notes, I'll probably copycat you on my install.
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Jul 8, 2017 23:53
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Bozart posted:Where is the upstairs thermostat? Under the return near the two rightmost rooms.
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Jul 9, 2017 02:12
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Yeah, so upon further measuring getting this one down to the basement through the wall wasn't happening. So I pulled out the hole saw instead.  On to the next one. Oh....and the too short dry contact box cable? Also, hole saw through the side of the unit was the answer.  Tucked the box right up next to it just above and out of the way of the vent on that side. Ran the t-stat wire through the wall and outside along with everything else. I'll route it back in later on.
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Jul 9, 2017 19:32
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I bought this house two years ago during the winter and I didn't really notice until the following summer that the AC unit is installed under the deck. It appears that it was on the side of the deck prior to the previous owner expanding it. So now the AC unit blows hot air up at the deck that's about 4ft away. How badly is this hurting the efficiency? When it is in the low 90s the unit has to run constantly just to maintain a temp of 76. I had the coolant checked and it was where it should be.
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Jul 10, 2017 13:27
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Well, when you had the refrigerant checked, what where the pressures? Because, yes, not being able to vent the hot discharge is very much going to effect how the system runs. If it's just conastly suckling in its own hot air it's never really going to be able to run effeciently.
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Jul 10, 2017 20:59
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Kjermzs posted:So now the AC unit blows hot air up at the deck that's about 4ft away.
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Jul 10, 2017 21:43
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