Units are short cycling. Can I reduce refrigerant charge?

[joepc]

I have several rooms with wall units that are short cycling. They run for about 4 minutes then are off for about 6 minutes.

Would reducing the refrigerant charge keep them from short cycling? What other unintended consequences would result?

Thanks in advance!

[snupytcb]

how do you know they are over charged?

[kdean1]

You need to find out if they are actually short cycling or just under a low load.
What is the outside temperature when this happens?
In fact, give us more information. You say wall units - are these heating or cooling? What size? What brand and model?
Running the units undercharged will waste electricity and prematurely wear the components. Don't do that.

[joepc]

Thanks for the responses. More information below-

The units are 1 ton water source heat pumps that are always in cooling mode, the climate is tropical. The units are located inside the rooms they serve they do not have an outside air intake. The building has louvered windows everywhere. A test was conducted on one unit with outside temperatures ranging from high 70s to about 86. During the test the compressor cycle time was 10 minutes- on for 4 off for six, repeat.

Sorry if I'm using terminology incorrectly but I'm not sure about your comment regarding low load. What is the difference between and actual short cycle and a short cycle caused by low load?

[kdean1]

A low load (low outdoor temperatures) would need less than the full system capacity. It will satisfy the thermostat and turn off. At design temperatures a system of the correct size will run constantly and maintain the indoor temperature.
Short cycling is when the system turns off before satisfying the thermostat because of a system problem such as low refrigerant pressure or a coil freeze error.
The conditions in your description sound like a low load. How big is the space being cooled and what are the highest normal outdoor temperatures?

[joepc]

I agree, it seems like low load. I am ultimately trying to accomplish improved RH% in the conditioned space. In the current situation the compressor is only running for a short amount of time and the room is reaching set point but, it is not removing enough moisture.

(Assuming low load currently) would reducing the refrigerant charge keep the unit running longer and help with RH%? What are the downsides?

Are there other suggestions?

Thanks!

[kdean1]

Reducing the refrigerant charge is WRONG! I said that earlier. It is STILL WRONG.
The only solution is to get a smaller unit or increase the load.

[jtrammel]

Slow the blower down as low as you can while maintaining some superheat and keep the SST above freezing.

[timjimbob]

Compressors use refrigerant charge to cool the compressor motor. Lack of adequate freon charge will overheat the compressor motor. That is one reason why.

[syndicated]

Reducing the refrigerant charge is like pulling 2 spark plugs out on your V8 because you're burning too much gas and want a v6.