Compressor valves vs. Defective reversing valves can sometimes be hard to detect, particularly in mild weather. Weak compressor valves and bleeding reversing valves are usually characterized by higher-than-normal back pressure and lower-than-normal high-side pressure, as well as low system capacity.
How do you know if your reversing valve is bad?
When a reversing valve leaks, it leaks from the high side to the low side. To check for a leaking valve, measure the difference in temperature between the suction line from the evaporator and the permanent suction line on the reversing valve (usually the middle line on the bottom).
What is the most common problem with reversing valves?
One of the most common problems that can develop with a reversing valve is that is can get stuck. It may become stuck in a specific mode or in between modes.
What does a bad reversing valve sound like?
Sometimes customers complain of a “buzzing” noise coming from the outdoor unit, even when it’s not running. This is usually caused by the reversing valve solenoid coil. It’s usually a low voltage device (24 volts) and some are just louder than others – and in most cases, this is normal.
What controls the reversing valve?
A reversing valve operates by a pressure difference inside a metal tube, controlled by a solenoid. The pressure change moves a slider through the tube, and this slide straddles two of three tube openings. An electrical connection from the thermostat controls whether the reversing valve is energized or de-energized.
What can prevent the reversing valve from changing positions?
Most reversing valves stick due to a bad solenoid coil that lacks enough voltage to move the reversing valve. In some cases, the actual valve could be physically stuck, preventing the solenoid coil from moving the valve.
Why does air conditioner make a whooshing sound?
The “whooshing” sound you hear is made by a valve as it reverses your unit from the heating mode to the defrost mode. It’s like your unit is briefly switching over from heating to air conditioning. This way the heat gets directed towards the outdoors, melting the ice on the heat exchangers, instead of into your house.
Why does my outside AC unit make a loud noise when it shuts off?
The slamming noise is likely the damper closing after the AC shuts off. You may also be hearing loud creaking noises from the ducts expanding and contracting from pressure and temperature changes if you have sheet metal ducts.
Why does my furnace hum when it’s off?
The transformer in your furnace can also produce a humming sound when electricity passes through. Low humming noise in the furnace when it’s off could be caused by the transformer and the attached ductwork. Enlisting the help of a professional to reposition the transformer could resolve your issue.
What does O B on cool mean?
The O/B terminal is for heat pump systems and is used for the reversing valve. If you get it reversed the heat pump will cool in the heat mode, and heat in the cool mode.