Trane XR90 - 3 Red Lights

Tom Scott

What voltage should it read if it's working properly?

Sorry for the the questions and thanks for your help.

Doc Holliday

It's stated on the cap itself what the operating voltages should be but more importantly than what voltage it's holding is the microfarad it's putting out. As well, the mfd (uf) number is stamped on the cap.

raylo32

Unless I missed it one theing the OP never mentioned was whether inducer motor was running or not. That would be a useful data point.

Tom Scott

It runs.

Update. I have called for help and the first 3 companies I called said they are booking for next week. Finnally I got a someone and I am jsut waiting around for him now. I just hope he knows this model.....

NitroNate

the confusing thing is that from what you are saying, the unit is running and functioning properly with the hose detached from the pressure switch. the only thing i can deduct from that is that the pressure switch is somehow "stuck" in the closed position, because without a vacuum it would stay open and thus disable the unit. removing the hose under normal operating conditions would cause the unit to NOT run. if it IS running, i would think the pressure switch was the obvious problem.

hvactech126

an XR 90 would have a dual port pressure switch, if it runs with a hose disconnected that must be on the burner box side. check your intake, exhaust, and condensate trap. Remove the trap and run water through both sides until it runs clear.

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harleyrider

its not confusing at all.............the hose that is detached monitors the burner box for proper air flow for combustion.......take of the hose and take away the control boards ability to monitor the intake air.........hence a plugged intake...............i would be a dollar that if he put the hose back on, and took the burner box door off it would run as well.......if you have spare time.......check the cap.............

beenthere

Hmmm hmmm hmmm.

Can't we all just get along.

Post have been removed. Lets keep it friendly.

Tom Scott

Thanks, where is the trap?

Tom Scott

Nevermind the guy is here and it looks like it's draining fine.

Doc Holliday

Party pooper.

You know me, blood and broken bones is right up my alley.

Thanks.

harleyrider

the trap is easy to find, follow the condensate hoses into the blower area.....its white with 2 5/16 screws holding it in place.two clamps hold the hoses on......when i clean these i submerge them in a bucket of bleach/water (as hot as you can stand) along with the hoses, as they too can get a build up in them. the off white fitting attached to the base of the combustion motor is another well know choke point on trains, so remove and clean this fitting as well.

after saying all this I do not think that its a trap issue......but what I described is good annually maintenance.

harleyrider

please let us know what he finds............

Tom Scott

Tested it with a new pressure switch and he gets the same thing. Hes calling his boss now.

beenthere

Clogged/restricted pressure hose. Restricted exhaust or combustion air intake pipe. Corrosion build up on hose pressure ports. Restricted drain line. Crack in a pressure hose. Slow spinning inducer. Cracked heat exchanger. loose restricter plate on the back of the inducer.

The tech should use a manometer and see how much pressure the switch is seeing.