Yesterday I finished lunch and thought, "it's a bit warm in here."
I look at the thermostat and see that the AC is commanded 'on,' but there's no air moving.
The fan on the compressor is running, but the compressor itself isn't.
Panic activated!
Shanghai Marv and head to Home Depot!
Before I did that, though, I set the thermostat to 'off' and the fan from 'auto' to 'on'. House temp shows at 80°.
Bought a couple of window units.
When I go inside to start preparing to install the first unit I notice that there's prodigious air flow in the ducts.
I change the thermostat to 'on' and we install the smaller unit in my bedroom. House is at 82° and I seal off the bedroom because the cats will head out the open window while we're putting in the window unit.
A couple of hours later the central AC is still going strong. House is down to the selected 76°.
I think we froze over from too much humidity being sucked up the duct and that caused the stoppage.
We're going to leave the window unit though.
Back in 2008 we had hired a friend, whom worked for an AC company, to save some money and help them out on the central unit. I think it's been undersized almost since day one. Any clear day with an outside temp above 77° and the AC loses ground and will be 78-80° by the time the sun goes down.
My idea is the window unit will take some load off the house unit now and allow it to run less since the location of the bedroom takes the full load of the sun all afternoon and has the computers cooking away in it.
Our theory about the freeze up is that because the unit, being undersized, never shuts off, it never gets a chance for any humidity on the evaporator to thaw out. I like theories.
My idea is bolstered by the fact that without the bedroom in the loop it went from 82° to 76° in just a couple of hours. Prior to this it would take almost all night to shed from 78° to the desired 76°. I've long had a little thermometer in the register in the bedroom. It normally shows mid-sixties to low-seventies when the AC is running. Since the thaw it's remained at 60° even!
Click here to submit $0.00 US for a lifetime subscription
Posts
Comments
Try cleaning the indoor coil [evaporator] if its real dirty that will cause freeze up - Tex-
ReplyDeleteIt sounds like your evaporator coils froze up. That's from overwork, dirty coils, or low freon. Cleaning the coil may make a huge difference. You can buy a coil cleaner you spray on, and allow the condensation to rinse. It's usually available at box hardware stores. If the coil is really dirty, you might have to use a brush to remove some of the accumulation.
ReplyDeleteHaving that window unit for the bedroom will help a lot. Especially if you like sleeping in really cold air.
ReplyDeleteIt's the poor man's version of a zoned cooling system.
Sometimes a little 'help' is all that is needed.
ReplyDeleteI should add that those coils are clean. We once had rats in the attic who chewed into the intake trunk and thus allowed unfiltered air from the garage into the evaporator coils.
ReplyDeleteI cleaned that out but good, and lost ten pounds of water scrubbing the fins until air passed freely.
I still check annually, in March, to make sure that they're not clogged.
That it didn't freeze up again in the next 24 hours makes me think that the freon level is good.
That leaves us with overwork. Which the window unit SHOULD help with.
I'm calling it a qualified success because the central unit was actually cycling off and on just after sunset and the thermometer on the thermostat read 76. The week prior it read 78 at the same time of day with similar outside temps and sun and it didn't cycle off until near 2am.
I'm still finding my comfort level on the window unit, it's a simple dial thermostat. I have it about 1/16th a turn towards cooler from halfway. The fan on it runs continuously, but the compressor only kicked in a few times at peak heat and sun.
Had something very similar happen just before the isolation orders came down. Neighborhood guy came out as a favor, looked at it, hooked up the gauges and said, "You've got a tiny leak, and you need to add freon. It's low freon that causes the coils to ice over."
ReplyDeleteHe added several pounds of VERY expensive antique freon, the pressure held, and we started cooling again. It's been holding for weeks now, which pushes the day of reckoning off into the future.
Have someone with gauges come check, they won't even really have to enter your house, they can do it all from outside. If it's not a 20yo unit, and uses modern freon, it won't even cost that much.
Keep the window unit as backup.
nick
It uses the old freon and never has done a good job of cooling the place off because it's undersized.
DeleteNever shutting off is also a source of freezing over.
If the freon was low it would have frozen over in the hours it was running yesterday afternoon. Thankfully it didn't.
The day of reckoning is coming and we're going to have to upgrade everything, but we're going to stave that off as long as possible.
Probably until (to be grim) the inlaws have kicked and we sell off their house.
Two thoughts based on the comments, if the condenser is dirty, or the TXV is not working correctly, the machine will not work as it should.
ReplyDeleteYou can also put a dehumidifier in you bathroom. Run it after shower time and it'll take a huge load out of the house for the next day.
ReplyDeleteWe have a window unit in the Master Bedroom so when we have power outages, we have a unit that the GenSet can run and keep the bedroom cool enough to sleep. Doesn't happen often but when it does, there is no substitute.
ReplyDelete