Signs of a bad txv

During this HVAC service call I replaced the TXV on a newer 2 12 ton Trane system. So I could get someone to pump it down and swap TXV.

Bulb TXV head improperly positioned.

Signs of a bad txv. A restricted metering device thermostatic expansion valve or TXV can cause a number of symptoms in a system. Here are the ways a TXV can become restricted. Wax buildup in the valve because the wrong oil was used in the system.

Sludge from the byproducts of a compressor burnout. A bad TXV isnt the only possible cause of those symptoms even when it contributes to them. For example an underfed refrigeration system exhibits many of the same symptoms as a bad TXV.

Frost on the valve or coil. A low pressure reading at the suction service valve. High liquid pressure at the liquid line valve.

One of the most obvious visual signs that a TXV has lost its bulb charge is if the top of the txv is very rusted. That would be the leak point of the refrigerant. How long does a TXV last.

If it is in that range then the valve isnt bad. Its doing its job. If it is lower than 6 of superheat at the evap outlet then it could be overfeeding double-check your thermometer and gauges.

If the superheat is well above 14 at the evaporator outlet with the proper subcool and liquid pressure entering then you have a failed closed underfeeding valve. A TXV that underfeeds an evaporator can be observed by measuring a higher than normal refrigerant superheat value at the outlet of the evaporator. Although a defective TXV can result in either a higher or lower refrigerant superheat value it is definitely not the only possible cause.

A plugged TXV will underfeed the evaporator and produce symptoms that include the evaporator operating under a vacuum or very low pressure. A plugged valve will not respond to a superheat decrease or will suddenly open up if superheat is adjusted downwards. Some TXVs have an.

Easier said than done but this includes a visual inspection of the air filter evaporator coil and blower wheel checking all of the air handlerfurnacecontrol settings verifying you are getting the correct callssignals and then checking static pressure. Symptoms of a bad expansion valve. Car AC system isnt cooling enough or wont cool at all.

High side pressure is high. Air coming from vents is frosty. AC blows cold then hot.

AC kicks on and then immediately kicks off. Airflow drops dramatically from vents. Click to see full answer.

If its a bad TXV it wouldnt be so hard to fix it has flare connections and I can get exact model on e-bay. So I could get someone to pump it down and swap TXV. 07-26-2016 1018 AM 5.

During this HVAC service call I replaced the TXV on a newer 2 12 ton Trane system. The AC system was installed in the last 18 months so the part was still. Spotting Other Problems.

In one common symptom of a faulty TXV the coolant system goes through a series of short cycles that dont seem to. You have a package unit but bad txv on indoor coil will stop liquid flow. Suction pressure drops head pressure drops because liquid backs up in condenser.

Fan running drops liquid condenser temp and pressure Remove and heat the txv bulb while watching pressures. Valve should open cool buld valve should close. Sent from my iPhone using Tapatalk.

In this HVAC Service Call Video I go over the Diagnosis of a Bad TXV using Subcooling and Superheat to figure it out. You know there is a problem when the e. That doesnt really look like a bad expansion valve to me although it could be partially open causing such pressures.

It looks to me more like a weak compressor. Niether one of these scenarios would be very common at all. The only thing that usually happens to.

It is called a schraeder valve. The small line on the TX valve is a equalizer line and should not have a schraeder in as there is nothing to press it in. Refrig gauges have a tit which pushes it in.

The equalizer line is just a small line with a flare nut. It may not work now if that valve is in. In addition a blocked return air vent can cause a TXV valve to go bad.

Bad TXV valve symptoms. Its sometimes difficult to diagnose a bad TXV valve since the symptoms are similar to an underfed system. However some of the most common and easiest to identify bad TXV valve symptoms are.

There is frost on the evaporator. Your unit is blowing. A TXV can overfeed from restricted air flow return air blocked dirty evaporator coil dirty air filter or a bad indoor fan.

As you can see there are many outside factors that can cause a TXV to have exhibit problems other than the TXV itself. Continuous operation is another telltale sign of a bad TXV valve. If the expansion valve doesnt turn itself off because the sensor is faulty and excess of gas will.

There are many reasons why an expansion valve may suddenly go bad. Sometimes the parts are just defective. Other times clogging in the system will damage the part.

In many cases the part simply deteriorates due to age. Regardless of the cause fixing a broken expansion valve can be challenging and should only be undertaken by a professional. Bulb TXV head improperly positioned.

To fix this simply check the TXV if any of the previous symptoms are showing. Then you will need to check if the TXV is good for the device not too small efficient enough or if it fits the refrigerant valve. Then check for dirt or debris inside the TXV any leak or moisture that could be affecting it.

Bad Thermal Expansion Valve Another reason for frozen lines in an AC unit is due to a faulty thermal expansion valve also known as a TXV. This controls the flow of refrigerant through your AC unit. If this malfunctions then not enough refrigerant will pass through the system and the coils.

That will cause a freeze up. Read the full answer.