Picture of Austin Caldwell

Austin Caldwell

Technical Services Manager
North Georgia District

Pesky P201 Code

On 30RA to 30RB, this code can be a massive headache.  With all the different options for these chillers can come with this alarm can send you down many different paths. We will break down a couple of basics to look at first to get the chiller back online. If this code still presents the chiller will not run.

The P201 Code read out is “Cooler Flow/Interlock Contacts Opened During Normal Operation”. This alarm is from the flow switch losing flow while the chiller has a run command active. This is the main safety for the water side of the chiller. This stops the chiller from freezing the evaporator barrel. This is why you never jump the flow switch on any style chiller.

The first thing to look at when you have this alarm is to check if the chilled water pump is working. Once that is verified, check and make sure to use either a peach plug or the gauges on the piping. If you use the gauges on the piping, use only one gauge to pull the gauge from one side so you can have a standard. Once verified, pressure drop check the flow switch. Clean the flow switch if it’s dirty.

If the alarm is still present, replace the sensor – especially if it has been in the machine for a few years at least. Once all this has been checked, make sure you don’t have an external flow from the BAC. If that is all good hit the switch and fire the chiller up. These are some good steps to keep when checking water flow issues.

Disclaimer: The technical statements, information and recommendations contained herein are believed to be accurate as of the date hereof, but Mingledorff’s does not make representations or warranties, express or implied, as to its accuracy, its completeness, or the results to be obtained. The information is being provided for informational purposes only and is intended for use by persons having adequate skill and expertise regarding the proper selection, use and application of the products and recommendations and at their own risk and discretion. 

More to explore

The new Carrier 27VPA9

February 11, 2026 No Comments

This new unit is a noncommunicating variable 5 speed performance line  heat pump with InteliSense technology, 19 seer2.   Sizes range