Is HVAC Cycling Too Often? (AC)

   / Is HVAC Cycling Too Often? (AC) #11  
tallyho8 said:
It looks like it is cycling just right to me with more off time than on time. I like a unit that keeps the temp within 1 degree and runs for a short amount of time instead of a unit that lets it heat up 2 or 3 degrees and then runs for a long time.
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If you're using a two stage compressor and the load is sized correctly for the equipment size, you WANT more run time than off time. The power usage is in starting the unit, not running it continuously 24/7.
 
   / Is HVAC Cycling Too Often? (AC) #12  
Based on the information provided only the 1st stage is cycling on and off.

4 cycles within 3 hours is nothing to be concerned about and certainly not short cycling.

Wouldn’t have any worries about that run time.

I splurged on 2 variable speed compressor, variable condenser fan and variable evaporator fan, multi-zone Trane units include the new house. 7 zones in the house, I’ve been very satisfied with the units.

Units at cost, or I would have likely gone a different route as they are still pricey at cost!!
 
   / Is HVAC Cycling Too Often? (AC) #13  
bnold said:
Based on the information provided only the 1st stage is cycling on and off.
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If a system is sized properly using a two stage compressor outdoor unit in the middle of summer, and the 1st stage is cycling on and off (per the outdoor unit being on and off), I would be a little worried if it happened every hour. If the house it that well insulated, I'd be curious as to the load cal for the house to see the actual numbers. Generally, for AC for cooling, the load is done around in the 90's outside air temp (depending on location) for AC, at a 72-74F indoor temp.

2nd stage compressor is used to the maximum rated BTU/h allowed for cooling. Lots of times you don't need the maximum cooling, and this is where a two stage compressor offers you an advantage by only running in first stage.

All that said, we're basing our diagnosis off an unknown app that may or may not have anything to do with the HVAC equipment. If the electric bills are within norm, I'd guess the information off the app is incorrect.

EDIT - Might of missed it, but how long has the OP been using the app and how has it differed over time in the past per cycling?
 
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   / Is HVAC Cycling Too Often? (AC) #14  
It looks like nothing is wrong with this particular system, but you better ask a technician to look at it carefully. I know many guys that graduated from one of these https://www.onlytradeschools.com/hvac/ trade schools and are good HVAC technicians now. There are a lot of them in every more or less big city or town, and you will not have a problem finding one. I know that it is always better to have a recommendation from a friend or just a person you know so you can be sure that one or another contractor will do their job carefully. You can ask the people you know whether they can recommend a good HVAC technician, and I’m sure they will be able to help you.
 
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   / Is HVAC Cycling Too Often? (AC) #15  
Cycling has to do with current outdoor load conditions and house insulation. Manual J loads are designed so that the system can handle the upper and lower extreme conditions, so during shoulder seasons every system is oversized.

2-stage helps that out, zoning also. But under low load conditions a system will do all kinds of short cycling. What do you keep the set point at?
 
   / Is HVAC Cycling Too Often? (AC) #18  
5030 said:
Which is adjustable I hope you realize. Short cycling is usually indicative of low refrigerant level.
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To much/little freon, or a bad pressure valve.

I've had short cycles due to too much freon or a bad pressure valve.

Started out with a bad pressure valve. AC company topped up the freon based on ambient temperature after replacing the pressure valve.

When a heat wave came through, the system started short cycling again. That was caused by too much freon in the system for the temperature.

They bled off a little freon and then we were good.

The unit at work would turn into a solid block of ice when it got low on freon and was switched to heat

Tech would have to switch it to cool and let the outside unit thaw for an hour or so before they could get the door off to top up with freon
 
   / Is HVAC Cycling Too Often? (AC) #19  
Dftodd said:
They bled off a little freon and then we were good.
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There is so many things wrong with this statement that I don't know where to begin:ROFLMAO:

The bigger question is if the system was overcharged, why?

That said, a system over 10-15 years old, I can understand why it may be losing it charge over time.
 
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   / Is HVAC Cycling Too Often? (AC) #20  
Sigarms said:
There is so many things wrong with this statement that I don't know where to begin

The bigger question is if the system was overcharged, why?

That said, a system over 10-15 years old, I can understand why it may be losing it charge over time.
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There was a long story. When we bought the house, the fan motor went out due to a faulty pressure sensor inside and the unit short cycling.

Tech did a bush fix on the fan to get us back up and running till the correct fan motor came in. He had to drain and recharge the system when he replaced that sensor.

Tech promptly forgot about it I ran into the tech in town about 6 months later (middle of winter and really cold) and reminded the Tech about the fan.

So he ran out and replaced it. Apparently gave the system a top up on freon as well and got it a little heavy.

Didn't have an issue till Satan decided to show up with 130° temperatures in August (6 months after the top up).

Was working fine the week before with 110° to 120° temperatures.
 
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