|Posted by AC Contractor on September 11, 2014 at 10:30 PM|
Trane has issued a service bulletin regarding TXV failures and appears the solution also includes refrigerant additives. Below is an excerpt from the service bulletin, thanks to Andrew Singer for contributing:
The purpose of this bulletin is to address recent reports of issues with TXVs used in air handler and furnace coil product lines, predominately found in the 1.5-3.0 ton units. Reported issues include higher than normal superheat and lower than normal suction pressure which have generally appeared at start-up or within a short period of runtime (typically 60-90 days). This is a fix on fail action. This is not a safety issue.
We have brought back numerous valves from the field and a thorough analysis has been conducted. Findings to date show that a majority of the valves inspected contained debris on the push pin and spring. This debris on the push pin and spring may cause the valve to stick.
For TXVs that exhibit the low suction pressure (,95 PSIG) and high superheat (>30 degrees F), an oil additive needs to be installed into the refrigerant system. The addition of this oil additive has been shown to dissolve the debris on the push pin and spring assembly freeing up the movement of the push pin.
Repair and Installation Instructions
Add 4 ounces of MJ-X oil additive (CHM01005) to the refrigerant system while the compressor is running. Follow the steps on page 5 after the MJ-X is added to the system.
After adding MJ-X Oil Additive complete the following steps:
1. Operate the unit in the heating mode.
2. If the outdoor unit is a heat pump, place system in the heating mode of operation for 15 minutes.
3. If the system has a gas furnace, cycle off the air conditioner and cycle on the gas furnace for 15 minutes of run time.
4. If the system is an electric/electric system, cycle off the air conditioning and place the TXV sensing bulb in a bath of hot water for 15 minutes.
5. Place the system back into the cooling mode of operation and allow it to operate for 15 minutes. Note any performance changes.
6. Did the system performance improve to >95 PSIG Suction Pressure?
7. If yes, the MJ-X oil additive is clearing the restriction. No further work required.
8. If no, repeat steps 1-5
There is also a note that it may take up to 48 hours of operation for the system to return to normal operating conditions.
We expect further investigation into what in the manufacturing process is causing the debris to occur. As it currently stands, a technician should carry this additive on his service vehicle in case he needs it on any and or every installation. Although the solution is simple, it may become burdensome on the contractor by prolonging installations and additional callbacks. If you are wondering if your Trane system is one of the affected, contact Tampa's HVAC experts at Melo Air. We will be able to determine whether or not your system may be susceptible to a TXV failure.