Do thermostats have a lockout for the compressor

[Hobby_Man22]

I read somewhere that said it's bad for the a.c. compressor to kick back on after a short period of being off. Mine will kick back on after 6-8 minutes in the heat of the day if I have the thermostat set low. Like 70. I've read that it needs a good 10 minutes to allow the pressure to go down before restarting again. Is this true? I just have too many air leaks in my building and that's why it does that. Unlike a house where it will stay off for a good 15-20 minutes.

 

[rlitman]

I am not aware of thermostats that do exactly what you ask, but many smart thermostats will have programming to detect and possibly deal with short cycling.

I would suggest you replace your compressor contactor with a smart solid state unit that both prevents short cycling and brownout damage. Look into the Emerson 49P11-843 Sure Switch Relay

Also, perhaps you can increase the hysteresis range of your existing thermostat to extend the cycle times.

 

[Hobby_Man22]

I do believe it has a 6 minute delay when switching between heating and cooling mode (heat pump) but I dont know if that extends to cycle times also where it prevents it from starting again for 6 minutes.

 

[PoorUB]

Some thermostats do have time delays built in, most do not. 6-8 minutes between cycles is fine, don't worry about it. The short time they talk about is 30 seconds, or maybe a minute. The pressures in the system will equalize in a short time. You just don't wan the compressor trying to start when the high side pressures are still up.

 

[Bert_]

5 minute delay built into the thermostat is common. It's usually optional, you can turn it on or off.

 

[yeldogt]

Thermostats do typically have it built in now ...... there are also controls that you can put out at the compressor. It really depends on the age of all the components.

The old days with mercury switches -- no. You had to add it at the compressor. I first started seeing them built into the better condensers back in the 90's. With the advent of digital thermostats it seems the base units depend on the thermostats again.

Now the condensers have sensors and the thermostats talk to the condenser on the better units. If you are not holding temp for that short of a time you do have leaks/ insulation issues

 

[Terry D]

Most all thermostats have a delay, this allows your pressure's to equalize so the the compressor can start not under a load. I have also come across some condensors that also has a time delay in them