Trane XE80 furnace – system lockout

[network21]

Today our Trane XE80 (Model TUD060C936H3, with a White Rogers Model 50A50-473 control) did not ignite twice (igniter works, but I don’t think it turns on, or natgas does not turn on even though blower is on) — all other times everything works). Each time, I manually turned the furnace off (at the furnace) and the unit reignited when turned back on. (At least) once, the LED on the control unit flashed twice (which means “system lockout (no flame) check line polarity” per comments on the control unit). Thought it might be the flame sensor (from previous posters here), but when I downloaded the troubleshooting guide from the White Rogers website (Model 50A55, which it replaces), it says that 2 flashes means the pressure switch is stuck closed (one flash on the 50A55 is system lockout). But most of the time, the furnace cycles fine. Don’t want us to be gone sometime and the furnace doesn’t kick in. Any thoughts? Since it’s Christmastime, don’t know whether to try and troubleshoot this myself or call in “an expert”. I’ve tried looking for troubleshooting info for the XE80 at Trane’s website and haven’t found anything yet.

[HKestenholz]

This is the problem that many don’t like to hear. To be secure about a heater firing consistently, not only do parts have to be cleaned and moved around back to where the factury had them; but pressures and temperatures have to be measured and set as they stray. It would be nice if it only took parts changing after a few years; but the new ignitions have safety devices that are sensitive to air pressure, combustion pressure and gas pressure, as well as temperature, as they follow the physics of gas laws while metals expand, contract, fatigue, and move over time. Contacts corrode and oxidize from acidic air.

Old gas furnaces with mechanical switches and standing pilots could be neglected for decades, so the less familiar with heaters will probably believe for another decade that heaters haven’t changed and they can get away with no annual service. It’s been about ten years since electronic ignitions have been in most gas heaters and it takes about 20 years for institution ideas to change.

When the electronic safety ignitions start giving problems, the gas heater needs to be looked at completely, completely cleaned, and everything tested and adjusted with sensitive instruments. Homeowners have the choice of learning the HVAC trade and gaining enough experience to have and use all the test instruments as well as a factory-trained and experienced tech – or make a more productive search for someone who is competent to complete a factory check-list maintenance and adjustment procedure every year.

A first step could be to clean the intake and exhaust completely to see if it lets the unit work. Then clean and tighten the electrical connections and flame sensor. After that, it is time for the sensitive instruments.

http://www.heatpro.info heat/cool right-sizing

The Senate and House can not find a suitable health plan for the nation; they should open their own exclusive health plan booklet and start reading.

[Unregistered-mytraneofftrack]

cleaned the sensor with sand paper but still having the same problem – very frustrating.

[sharkie2]

Mind telling me how this was fixed? I have the same problem.

[Author]

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