x13 blower motor and general AC question

Old 11-17-19, 01:55 PM
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x13 blower motor and general AC question

Quick backstory. Visiting my parents in Southern Florida. Noticed their AC was short cycling and not really bringing humidity low enough. It was anywhere from 55-65 RH , with the norm being above 60% Rh. Its oversized for a condo unit in the middle of the building, but they are not changing it out anytime soon.Got some advice on a HVAC forum, and one suggestion, from a member with thousands of posts, was to put a high Merv filter in to slow down the air to remove more humidity. I put in a medium filter, FPR 5 which is like a Merv 8, two days later my blower stopped working completely. I feel the 2 are related but every member on that forum is saying is is not possible.

Now to the blower that doesn't work. Its a X13. Exact model number is 51-101879-04. 1/3 HP ECM motor.
I tested the L and N wires going into the motor and got 240 volts on my multi-meter, so its getting constant power
I only have 24v wires going to my motor. The X13Com (common wire), X13SPD (blue cooling wire), X13G (green and black wire for fan on) . With the multimeter on common I am getting 25.2 volts at the end of the wire for cooling and 25.2 volts for the the fan on. The X13SPD wire is going into number 5 speed on the motor, and the X13G is going into the number 1 speed in the motor.

So if the motor is getting 240 volts and when the thermostat kicks on the other 3 wires are getting their 25 volts. Then can I assume the motor is dead?
Is there anything else that could be going on / that I should check?
Old 11-17-19, 02:22 PM
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Unfortunately the flaw in that logic is reducing airflow by using a highly restrictive filter causes the motor to run hot and you run the risk of the evap coil freezing.

How old is the system ? It may still be under warranty.

There are many threads and you tube videos on line where they show repairing that motor. There is a varistor in the end cap that can burn up. If the board is not potted..... that is an easy repair.

Mars makes some very affordable replacement X-13 motors in the $200 range as opposed to $500+ for a true X-13. Several members have installed the Mars with good results. Search for [x-13 mars]

X-13 motor
Old 11-17-19, 02:30 PM
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One person suggested that reducing air flow actually lower amperage use, and that was a good thing.

I believe the x13 models are all potted with black epoxy. The ECM 2.3 and 3.0 models you can get to the board, de solder and put in new thermistor.

However I did read a youtube comment that said to just break up the thermistor on the potted models so that you have some bare wire and solder the new one to that. However I haven't seen anyone do that.

Unfortunately the unit is 7-8 years old. I don't believe Rheem warranty is that long, though I'm not sure

PJMax would you say based on the readings I'm getting that my blower is def dead and thats the issue?
Old 11-17-19, 10:53 PM
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It sounds like you need to replace the motor to me.

An ECM X13 motor has multiple low voltage speed taps. The factory setting for airflow is often 400 cfm per ton. 350 cfm per ton is a better setting to reduce humidity.

The air handler is often slightly larger than the outdoor unit. This can make the humidity even worse if the installer doesn't set the airflow for the condenser in use.

If you had a 2 1/2 ton outdoor unit and a 3 ton indoor unit and the indoor unit was configured for 400 cfm per ton the airflow would be too high. 1200 cfm instead of 875 will cause a humidity issue.

A manometer is required to properly set airflow. ~$40 on Amazon.

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