Instead of using a centralized thermostat, a typical ductless heat pump relies on a handheld remote for fan speed and temperature control. From time to time, you may find the remote non-responsive to your desired inputs. Whenever this happens, you'll want to track the problem down with the following troubleshooting tips.
Check the State of the Batteries
As you troubleshoot your remote control, make sure you check the batteries first. Many problems that have occurred with ductless heat pump systems have turned out to be a simple case of the remote control's batteries dying unexpectedly.
First, remove the batteries and make sure there's no greenish or white corrosion residue on the remote control's battery terminals. If so, carefully clean the terminals and discard the old batteries, as the old batteries may have leaked corrosive liquid onto the terminals.
Next, replace the batteries with a fresh set, according to the instructions for your ductless system's remote control. The vast majority of remotes use AA or AAA-size alkaline batteries, but it's not out of the ordinary for remotes to use CR2032 lithium batteries (the same type of batteries commonly found in hearing aids and other small devices).
When replacing the batteries, make sure to align the positive (+) and negative (-) ends as shown in the diagram located on the battery door or in the user manual.
Make Sure the Unit Has Power
If the above step fails to fix the issue, then you'll want to make sure there's power going to the actual ductless heat pump. Locate the power switch on the wall-mounted air handler unit and make sure it's set to "on." If the unit remains unresponsive, check the ductless heat pump's circuit breaker and reset it.
After resetting the circuit breaker, the unit will usually operate as normal. However, if the unit fails to respond after this step, you'll need to check the main power switch near the outdoor condenser cabinet. Make sure the switch is set to "on." If all else fails, have an experienced electrician inspect your home's wiring to see if there are any problems preventing the unit from receiving power.
Keep the Remote within the Unit's Line of Sight
Unlike a traditional thermostat, your ductless heat pump's remote control relies on an infrared connection to a receiver on the wall-mounted air handler. It's important for the remote to remain in the receiver's line of sight; otherwise, the remote won't function properly.
Make sure there aren't any obstructions in the way of the remote control and the receiver on the air handler. If the remote control is mounted on a wall bracket, make sure the bracket allows the remote to be in clear sight of the receiver.
Make Sure the Remote is Clean
A malfunctioning remote control could simply be the victim of dirt and debris. Use a can of compressed air to blow away any dirt and debris that's become lodged within the remote's keypad and other internal components. You can also remove the battery cover, take out the batteries and blow out any dirt or debris you happen to find within.
One thing you shouldn't do, however, is attempt to disassemble the remote control. Not only is it often difficult to put the device back together after disassembly, but there aren't any user-serviceable parts inside. If there's an internal problem with the remote control that requires more than a battery change or a thorough cleaning, you may want to have it replaced instead.
Knowing how to troubleshoot your ductless heat pump's remote controls can help keep your heating and cooling system relatively trouble-free throughout its life.