Old carrier unit trouble

the pressure within the system might be rising to a point where it trips the hi pressure switch which might need the manual shut down start up....how long do you wait before turning the outside disconnect back on?the outside temps and the sun banging the condenser are the problem..if it was a capacitor problem or electrical it wouldn't run during the cooler nights...piping sound tight with the original charge still there...good hsing out of the condenser might be the fix.....how does the liquid line feel :furious: coming out of the condenser..in the PM and in mid day average is warm at 80F compressor running..if it is maint. the night it has to be cycling and restarting as normal....do you have a digital stat with a compressor off time which allows the pressures to equalize before the next start. i want to hear back on my inquires before telling you to add something..how often do you put guages on the unit..the hi side guage reading is more important for me to see what the pressure is running vs the inlet days temp...your house system reacts the same your car ac acts in the hot weather normal running pressures say in your nights 65PSI=40F at the air handler coil...250PSI with 75F-80F air into the condenser..if the outside changes with the days temps the hi side changes rising up,and that pushes the suction pressure up 70psi-80psi and there goes the temp at the air handler 40F...55F...65F supply

It’s noon here with 91 degrees and 43% humidity. Unit was running fine all night cycling on and off with no problem. This morning it was again 50 degrees at the register and currently is still running ok, the high pressure line is warm, not hot and the suction line is nice cold and wet. Still have not taken a high pressure reading but with the way its running since 5:30PM yesterday I figure it’s got to be ok. Of course that may change in 2 or 3 hours if and when it goes into “trouble mode”. When that happens the unit keeps running, never shuts off, suction line feels barely cool high pressure line feels hot and temp at the register is about 70-75; I’m totally perplexed as to really what brings it back on after several tries of turning it off for about 20-30 minutes, then back on and moving the thermostat dial from one end to the other. If thermostat were bad I would not get the cold temperatures I’m getting once I have it going again late in the day, no? One little item I need to add here. I asked about the run capacitor on my son’s recommendation. I was out oftown and just this morning my son tells me that while I was gone a 6”-8” wire between the run capacitor and the contactor had fried completely, one end to the other and he replaced it with 8 gauge piece of wire whichgot the unit going again. So it seems all of this started when that wire burned; I didn’t know about this yesterday when I posted. Took the covers off this morning as I did yesterday, everything in the control box looks clean, the contactor looks like new, no other burnt wires and the run capacitor is clean with no bulges No digital stat and I hosed the condenser coils twice. As of now the unit still runs cold, temp at the vent is still below 60 but today I got the thermostat set really low (71). We’ll see what happens in the next few hours and I’ll post. I’m not a pro by any means and most of what I know about HVAC I’ve read; am trying to avoid calling a technician, too expensive and in this town they all want to sell you something rather than work on something as old as this unit which really has been relatively trouble free; certainly no problems like I’m having now. I’m just an old geezer trying to survive on SS.

ok so withthe cap and contactor wires cooking thats telling me the compressor is trying to start on a short cycle and not having enough time to equalize from the last cycle:huh: the pressures run as i said 260psi + hi and 65psi suction cold line....when the unit cycles offf from the stat it needs to balance those pressures before the next cycle if they dont and the stat calls the compressor will never start and draw very high amps(burnt wires as found) might consider adding a time delay relay http://www.bestbuyheatingandaircond...egory_Code=r-compressor&Product_Code=REL203AA in the condenser in line with one of the 24v control wires from the stat coming in.do you have ant electronic boards either in the condenser or air handler??? the resetting of the stat to get it to run is sounds like something is locking your condenser and waiting on a 24V reset when you work it.have your son check the compressor contact see if its arc'd on the contacts might need changing with the compressor trying to restart against that un equalized pressures...i'll check back...NOTE if you go to start it right after it goes off you will not get the compressor to run only do it 15minutes after the first time it trips off...keep note on that Liquid Line as it gets hot as the day temps rise...it may look clean but the coil might be blocked between the coils ...the heat rise on the LL with the days temp rise willl tell me that...:thumbsup:

Well, as expected it did it again. About 3:15PM, 106 outside, 10% humidity, suction line cool but not cold, high line much warmer as was this morning when all was well and uncomfortable to the touch, air at register about 73 with the house warming up fast. Shut it off and waited 30 minutes, turned it back on - no improvement, watched it for 10 minutes - no change. Here comes the kicker! Went to the thermostat and sharply turned the dial from one end to the other 3 or 4 times and immediately it kicked in, air temp at the register dropped almost immediately and is now back at 60 with the suction line back to normal but the high side still uncomfortable to the touch. Is it just my imagination or could it be caused by the thermostat after all (weak voltage)? No electronic boards on this unit! Only circuit board I know of is on the inside of the house at the furnace. I'm almost embarrassed to do this but the Carrier model # of this unit is a 38GS045300 which makes it almost 40! Same goes for the furnace. As I have already stated, I never have had any major problems other than what was caused by power surges because the city had me hooked up 400 yards away, after an apartment complex and multiple duplexes I was the last on the grid. I used to mysteriously lose TV's, VCR's, Coffee Makers and Micro Waves too. It all changed back to normal when we had one really strong thunderstorm one night and the AC was going haywire, surging up and down, making a racket. When the guy from the power company showed up he was aghast at how far away they connected me when I had a pole right in back of my house. He made the switch and that took care of that problem. Anyway, could it be the thermostat? Whatever needs to get done will have to be by me and/or technician. My son was just house watching and knows less than I do; smart enough though to check the control box and find the burnt wire. AC is still working fine at 5:05PM.