HVAC issue home

Reaching out to see if any HVAC techs on here can help out . Having an issue with a ac unit at the house and could use some advice and suggestions .had a tech out and wasn’t able to diagnose the issue . I have a Goodman 2ton 7 years old .. it won’t blow cold ac at times when it cycles . Tech said coolant pressures are good . No electrical issues he can detect .brand new compacitor .I have to cycle the thermostat to get it to work . It will blow cold then once it turns off same thing stops blowing cold . Till it cycles again . I’m at a lost what the issue is and the ac tech wasn’t able to figure it out . Only suggestion he made was get a new ac . Thanks all

 

My brother had a Goodman…but it was far from good

 

Don`t call him again!

What kind of thermostat do you have ??

The system starts and runs till the shutoff temperature shuts the system off.

Then it cycles on but blows room temperature air .

Will it blow cold again once you cycle the system off and on.

Have you ever cleaned the condensing unit?? I need to clean mine every year at start up.

It also helps to clean the evaporator and keep up to date with filter changes.

What happens in my case is the heat does not transfer fast enough.

In high humidity conditions your evaporator coil can freeze up.

This is much easier up close and in person.

 

Is it a package unit or split system? Heat pump? If it's a heat pump could be the reversing valve sticking. That's the valve that switches from heat to cool and vice versa. Could be a pressure switch going bad. It's basically a process of elimination, possibly the thermostat is going out.

 

When you say “it won’t blow cold at times” how often does it happen? So it blows air inside just not cold correct??
When you turn off and turn back on the thermostat the compressor outside turns on after a small delay or after a while??

 

Without any more info, and if your thermostat runs off of batteries, I would replace them.

 

Honeywell thermostat

I have to cycle it multiple times till it finally blows cold . Checked temp at source showing 58f blowing when it doesn’t 80f
.
It’s a split system . Ac on the outside and heater and blower in the attic .

there is a small delay before the ac starts blowing not long . Maybe 1 min or less . Either blow cold or warm .

It seems to not work at random . Not specific to how many cycle it goes threw .

 

If I was your service tech, I would replace thermostat batteries (if it runs on them), check that I’m getting 24v going to my condenser every time the thermostat calls for cooling (could be as simple as a loose thermostat wire, or bad thermostat). If that checks out I would check board on condenser or coil on the contactor.

 

1) You need to determine if the compressor is running when the condenser fan is.
2) Fan motor going south and not able to remove enough heat leading to over temp protection to kick in for compressor?
3) Sounds like a relay could be dropping out.
4) Have you checked the larger pipe to see if it's cold when it's blowing warm air?
5) It could be a run capacitor issue. It could be over heating if the fan isn't running up to speed.

 

What model number is this unit?
Is this a heat pump?

 

Also check for a short in the thermostat wire

 

System is working at times transformer would most likely blow if there was a short on the low voltage side

 

OP is this a programable T-Stat?

 

Now it gets interesting an intermittent issue!!

A failing relay ?

Evaporator coil freezing .

 

OP is there a time delay device on the AC unit outside something that looks like this?

 

Does the power company have a energy saver on the outdoor unit we see the around my area sometimes and cause nothing but problems

 

OP how good are you with a multimeter?

 

1st thing I would do is change filter and clean the coils, inside and out. Usually it's always something simple.

 

Contactor unit or time delay issue is my guess.......or possibly a problem in the LPCO switch or circuit if it is equipped with one.

 

OP do you have a control board on the unit outside?


Light status What it means
Solid on - No connection to thermostat Check thermostat settings. Check power to thermostat. If that doesn’t help, call a pro.
Blinking - on and off Furnace ignition failure Turn furnace off and back on. If that doesn’t help, call a pro.
Rapid blinking - Power supply polarity reversed Call a technician.
2 blinks - Blower or pressure switch failure Check if there’s been a short or blown fuse. If that doesn’t help, call a pro.
3 blinks - Pressure switch open Call a technician. This isn’t a DIY fix.
4 blinks - Primary limit switch open Replace air filter. Open vents. Ensure exhaust flue isn’t blocked. Check power supply. If that doesn’t help, call a pro.
5 blinks - Flame present but no call for heat There could be a gas leak. Turn the furnace off immediately and call a technician.
6 blinks - Reversed polarity Call a technician..
7 blinks - Low flame Call a technician.
8 blinks - Igniter circuit failure Call a technician.