ReplyTxv for a metering device? If so there's not much else that could have the compressor and fan operating without cooling,not intermittently at least.
Member
but I hope someone can.
It's a Rheem RHPN-HM2421JC A/H with electric heat, installed vertical in a closet.
The cond unit is a RARL-024JEZ two stage.
Thermostat is a Rheem TST305.
T-Stat is configured for two stage cooling, and no daily program.
The customer says it runs fine all day but stops cooling somewhere between 2am and 5am. He says he looks out the window and can see the cond fan running and hears the compressor, and reach his hand to a grille nearby and it's blowing warm air.
Then around 6am it's cooling fine again. It happens every night.
There is no power company call box that would shut it off.
I have checked everything, I won't even bother to list it all because of the specific time that it blows warm air. It obviously works when I'm there.
We can have a 95 degree day and it works fine all day, but had this problem the night before and the next night.
The board in the cond unit reads no codes.
The guy is in his 80's or close to it I would guess.
What do you think?
Professional Member*
Txv for a metering device? If so there's not much else that could have the compressor and fan operating without cooling,not intermittently at least.
Professional Member*
Condensing unit on the west side of the home and in the sun in these hours? Could be thermal in nature and compounded by an overcharge. Either that or something is parking on the fan grille every afternoon about that time of the day. Some critters have strange behaviors. Ants in contactors, never have figured out that attraction....
Member
Well no, here in FL the sun isn't out between 2am and 5amOriginally Posted by Juan Madera
How could it be anything mechanical when it fights 95 degree heat fine but blows warm between 2am and 5am?
Professional Member
I think the electric heat is kicking on some how and that would explain the warm air. Maybe the stat is messed up causing that problem.
Regular Guest
Could you try unhooking the electric heat just to eliminate that as a possibility?
Professional Member*
Sounds like an old man with blood circulation problems.
Professional Member*
oops.... missed the AM part. Was thinking PM...
Professional Member*
I was also thinking a wiring issue with heat on...possibly the tsat set for heat pump accidentally? Or there is a crossed wire? Or even a relay or sequencer that's getting a signal..if he is telling the truth and not imagining the condenser running...maybe the stat is satisfied and fan in circulate mode.
Professional Member*
Unhooked the w2 from condensor board to eliminate that as a possibility.
And see if Rev valve is energizing or if its just strips
Professional Member*
Could it be moisture in the system freezing in the txv?
At what temp does he set the stat at night?
I miss you mom and dad.
Regular Guest
How much heat gain does this place have that he notices it not cooling for couple hours in middle of night.
Professional Member
I was thinking rev valve as well.
Possibly hanging up intermittently
Professional Member*
Swap thermostats and see what happens. Just use a basic one. I would also throw the breaker on your electric heat. Won't need it till January if then if it is Daytona or further South. Also JP and others he did say "electric heat". This is Florida. South of Jacksonville they don't use that many heat pumps. Just air handlers with electric heat. Hey and if they have a HP they normally wouldn't have a heat strip to back up the HP which is rarely used. That's all folks.LOL. Thank you very much
Last edited by glennac; 06-22-2012 at 08:58 PM.
"I could have ended the war in a month. I could have made North Vietnam look like a mud puddle."
"I have little interest in streamlining government or in making it more efficient, for I mean to reduce its size. I do not undertake to promote welfare, for I propose to extend freedom. My aim is not to pass laws, but to repeal them. It is not to inaugurate new programs, but to cancel old ones that do violence to the Constitution."
Sen. Barry Goldwater
Professional Member*
Well on rheem its piped energized in heat. So something would have to trigger it. Defrost board shouldn't as it opens Rev valve circuit. And should stop fan.
I too have a problematic unit I need to go back to. It is a trane rather. I do think mine energized w2 stopped cond fan and felt it needed to defrost in cool.
Professional Member
I would rule out the rev valve seeing as its not a heat pump. Disconnect the W1 from the air handler or turn off the breaker for the electric heat.
Member
It's not a heat pump.
I did think of the heat coming on, last time I was there I did think about going right to the source with the heat and taking the high voltage wires off.
The first time I was there I replaced the thermostat because the LED didn't light properly and it was under warranty.
I did talk to the guy recently, he said he keeps it at 76 during the day and turns it up to 78 at night (quite the opposite of what most people do), this might be a heat gain issue, as in it hits 78 between 2am and 5 am. I told him to leave it at 76 tonight.
The system has to be working right, he has a ton of eastern exposure so when the sun rises, around 6am, when he says it starts to work again, well I don't know. The cond unit takes a direct hit from the morning sun, right when he says it starts working.
He has just about no western exposure so I'm guessing the house is out of the sun by 5 pm or 6pm.
This is why I mentioned he's old. Years ago I was getting repeat calls like this. It would get hot at night, the guy told the office to not send me out anymore, two days later he died in his sleep.
Regular Guest
About 10 years ago I ran across a similar problem. Elderly woman complained her a/c would blow warm air. 2 visits and found nothing wrong, other than a slightly dirty condenser coil. 3rd call and I sat her down and had her explain to me EVERYTHING!. She neglected to tell me this would happen only at night and the outdoor unit she claimed was running. She lived in a manufactured home. Heat load was enough that the unit ran all day. At night the heat load would drop and the unit would cycle. What she thought was the c/u running was only the compressor (until it tripped on thermals). After cycling the cond fan motor countless times the problem showed up. A "dead spot" in the windings. It ran fine all day because it never cyled off. At night when it cycled the fan would occasionally stop in the wrong place and then lock up. As the early morning hours roled around the call for cooling would drop and the fan would free wheel a bit and fire back up in the daytime. She was also setting her t'stat higher at night. So it proved to be a bad cond fan motor
Member
This guy has a real good view of the cond unit, his house is built into a hill. In the front it looks like a one story, in the back it looks like a two story (if that makes sense). But I've looked at it and you can see the fan very good.
But then again, at 2am I doubt theres enough light. Maybe I'll ask him how he can see the fan at night.
This system does cycle during the day. I've been there at least four times before 11 am and the thermostat was satisfied.
Professional Member*
Is it an auto changeover stat
Posting Permissions
