Home AC

[TwoBallScrewBall]

My house AC seems like it's starting to fail. <br /><br />House and AC unit are both 4 years old. <br /><br />During the day (it's been hot this summer) the temp in the house will rise to 78-80 by the time late afternoon arrives. Overnight the temp will go back down to 72 where the thermostat is set. My house is occupied 24X7 so no time to shut it down, and it runs what seems like 24 hours a day. <br /><br />My dad babysits for me while I sleep during the day (I work nights). He said only over the past few weeks or so has this started to happen. <br /><br />The vents all blow air out, and the air coming out of the vents is cold. <br /><br />Upstairs the rooms stay very cool. The vents upstairs get so cold that they get condensation on them sometimes.<br /><br />My furnace, ductwork, and blower are all in the attic. The compressor is outside at ground level.<br /><br />Long shot, but anything I can check before I call a repair guy?

 

[TwoBallScrewBall]

Re: Home AC

P.S. I am going to check and clean the evap and condenser coils tomorrow. The one outside looks pretty easy but the one inside is going to take some surgery to get to. No access panels that I saw, so the ductwork needs to come apart.

 

[Bart Sr.]

Re: Home AC

Make sure any filters you have are clean or have been changed recently.My unit requires a fresh filter monthly.

 

[TwoBallScrewBall]

Re: Home AC

Thanks. Yeah I'm wondering if that might be the problem. About 2 months ago I bought a plastic washable filter from home depot. It's not fabric it has a wire or plastic mesh that's supposedly got a static charge to it. I checked it about a week ago and it was clean. Maybe too clean, as in maybe the dust is all in the damn coil. I'll be heading up to the attic when I get home from work and I'll let you know what I find when I get the ducting apart.

 

[SS MAYFLOAT]

Re: Home AC

SN, When you look at your condenser coils, they may look clean, but in between the fins can be packed full of debris. When you flush them out, always go the opposite direction of the air flow. Spraying them with the direction of the air flow can pack the stuff in there making it more difficult to get out.<br /><br />With the extreme heat these past couple of weeks, lots of units cannot overcome the outside heat beating down on the house. Sometimes running a mist of water on your condenser coil will help keep down the high head pressure on your compressor. <br /><br />When outside temps are above 95, AC units work the hardest and as the temp goes up outside even more than 95, it gets even worse. This is where geo thermal units work excellent.<br /><br />Try keeping all out all sunlight entering the house. Pull the curtains or whatever you have. Keeping the sun out can make a difference also.<br /><br />Good Luck

 

[rwise]

Re: Home AC

In the hot and very cold time of year I cover most of the windows with Styrofoam sheets. cuts cost, and during the hot part of the day I will often go out and spray the roof with water and the condenser coil/s. My wife says you can feel it in the house when I start. 56* here this morning, it.s a cold wave.

 

[Bart Sr.]

Re: Home AC

If it is that clean it isn't stopping anything.<br /><br />I would follow Mayfloat's lead on this one.

 

[tomatolord]

Re: Home AC

I would add to the above..<br /><br />My problem was a clogged water drain - the drain that drains out the air exchanger was clogged up and the high amount of water created made the unit inefficient. Unscrew it from the air handler and make sure it is clean and angled correctly, mine was clogged because it was angled wrong.<br /><br />Next thing to check is the Duct taping of the unit in the crawl space Duct tape does not last forever and 4 years is about the right time it starts to fail...so go in the crawl space with the unit on and see how much the air handler is leaking around the edges. I had a unit one time that had visible gaps around the edges of the air handler - after years of vibration it just worked loose.<br /><br />Next have the freon checked - cold air is relevant - it sounds like the unit is putting out JUST enough cold air to cool things off. Many HVAC guys do this on the side so ask some friends if they know someone .<br /><br />You mentioned upstairs - on MOST if not ALL - 2 story houses their is a lever somewhere in the duct work to switch between summer and winter basically this is somewhere near the air handler right before the split between upstairs ductwork and downstairs, make sure that the lever is in the summer position, which directs more air upstairs - cool air falls down and dont forget to switch n winter hot air rises, I have seen these levers closed because the owner did not they existed. Just make sure the air is properly divided between the upstairs and down - it might mean the lever is set to a 80-20 mix or 60-40 - it does sound like the upstairs is getting too much cool air.<br /><br />IF the outside unit is in direct sunlight it will struggle during the hot days - the solution as mentioned above is a misting unit to cool the coils, you can shade the unit but you have to be carefull not to restrict the air flow.<br /><br />Pour some warm water over the outside unit - or just hit with a hose sometimes the outside units frost over making them innefficient as well.<br /><br /><br />Good luck!

 

[kenimpzoom]

Re: Home AC

All above and check the intake ducting. We once had a problem where the blower was sucking hot attic air instead of from inside the house.<br /><br />The fact that the filter is clean leads me to suspect this may be your problem.<br /><br />Ken

 

[TwoBallScrewBall]

Re: Home AC

OK I went up there. <br /><br />Sweat my b***s off. <br /><br />The coil was clean. Sparkly. I could see light through it. When I turned it on without the air returns on it, it was blowind a whole lot of pretty cold air. I still sprayed through the coild from outside to in with a hot bottle of spray water with a few drops of dishsoap in it. Even the water running off it was clear. <br /><br />I'm going to check out the outside unit next. I know that I looked last week and there is about 4" of the coolant line exposed going into the house and it was cold and wet. It is fully insulated the rest of the run.<br /><br />Keep the ideas coming! I don't need to spend any $$ right now! Not on the A/C anyway, I need to save it for GAS.<br /><br />Thanks!!

 

[SS MAYFLOAT]

Re: Home AC

Sounds like it is operating like it should. The small line should be warm, not hot. The Bigger line should be cool or cold and it will have condensate water on it.<br /><br />I would not use warm or hot water to spray on your outside coil while the unit is running. This will cause your head pressure to raise. The colder the better for the water. <br /><br />If this does not bring your inside temp down, I would say the unit is a bit undersized or the heat from the sun is overcoming your unit.

 

[TwoBallScrewBall]

Re: Home AC

OK the outside unit I can just about eat off of. Not a leaf or anything in site. I didn't even bother spraying it down, it's barely warm. <br /><br />The air coming out of the coil box upstairs is cold. It's barely 80 today (79 last time I checked not 85) and my house is 76. <br /><br />Any more ideas? Something is not making sense here. Compared to the open duct in the attic, how much pressure should there be it the room vents? In the attic, standing in front of the hole, if I had hair it would be blowing around. In the rooms you can just feel a cold draft if you stand under a vent. Is this right?<br /><br />Thanks for the help so far.

 

[SS MAYFLOAT]

Re: Home AC

Was the air on the outside unit hot 100*+ or warm being lower than 100? If it is hot and blowing, take a piece of paper about the size of a letter. Put it on the coils in different places. If the paper stays on the coils, then you should be okay. At least that is a simple way that I check to see if the air flow is adequate.<br /><br />If the air is below 95 or 100 coming out of the condenser, this is also a sign of low refrigerant.<br /><br />Is there a sight glass on your small line leading into your house from the outside unit? A sight glass is a fitting in the line that has a glass lense. If you have one, see if you have bubbles running through it. If you do, then you are in need of some gas/freon. It is possible that you have a very small leak and is probably on the low side or the big line coming from your evap to the condenser. <br /><br />It sounds like you have pretty much covered all the bases Stiff Nibbles. You have done just about all there is to do. Sounds like you may have to get a tech to come in and put his guages on it to see what your pressures are operating at. When he is there, watch or ask to look at the pressures as he does it. The high side (usually the red guage) should be around 185 on up depending on outside temp. If the high side is reading lower than that and the blue guage or low side is then showing say 55 up, then you have a weak compressor possibly.<br /><br />If the high side is lower that 185 and the low side is lower than 55 or 60, then it is low on refrigerant.<br /><br />This is rough trying to diagnos without being there. Hope I have helped you some and not confused you.<br /><br />I don't have a temp/press chart here with me so those figures are a ballpark figure.

 

[gunslinger10mm]

Re: Home AC

Check the attic vents in the roof and in the eaves to make sure they are not blocked. If the hot air in the attic cannot be disappated, it can radiate back into the house. Also, the supply runs should only be 6 or so feet of insulated flex and the rest hard pipe that has been insulated (wrapped). If more flex than that was used, it can really cut down the air flow. In an attic, All the duct work should be insulated. If you were low on freon, the coil would freeze into a block of ice and you wouldnt get much air flow. Ditto if the airflow were restricted by a dirty filter.

 

[TwoBallScrewBall]

Re: Home AC

Yeah my last house had a restriction I wasn't aware of and it froze the coil. Had a tech come and he opened the thing up and it worked great after that. <br /><br />I've been over this thing a few times now. I found a power cable stapled down over two of the vents that lead downstairs, compressing the 5 or 6" tube maybe 1/2 way. I freed them up. I also checked the outside, it holds paper. But I doubt it's 100 degrees blowing out of there. Outside ambient topped around 83 today I think. <br /><br />I have a pretty much steady tiny stream of water coming from the condensate drain. OK?<br /><br />SS You're not confusing me I get it and I really appreciate the advice. <br /><br />Gunslinger some of the return vents are over 6' of insulated flex. It's 10" diameter on the returns. Attic vents are clear, it's actually not taht hot up there I'm just a fat *******. There is a nice breese blowing clear across the underside of the peak from one side to the other so it was tolerable up there. The long metal registers that distribute the air to the flex that runs to the vents are not inslulated on the exterior but I think maybe on the interior because they are not that cold to the touch. The box around the coil had 1/2" foam insulation on the inside.