Trane RTAA

[seathop]

Am I the only one who shakes my head when I have to pull a sensor to check accuracy? Why doesn't Trane use wells for the sensors?

[zw17]

Am I the only one who shakes my head when I have to pull a sensor to check accuracy? Why doesn't Trane use wells for the sensors?

I service quite a few RTAAs and RTWAs.

I want to pull my hair out every time I have to check or change a sensor.

I have taken more "Trane oil baths" than I can count.

[Healey Nut]

Am I the only one who shakes my head when I have to pull a sensor to check accuracy? Why doesn't Trane use wells for the sensors?


Thats what that fancy chart in the IOM is for , you know the one that compares resistance to temperature ??????????

[seathop]

Reading the fancy chart is easy, how do you get an accurate temp. reading of the sensor, especially if its submerged in glycol in the chiller barrel or inside the suction line ect. sensors whos inputs dictate chiller operation must be accurate, thats why they recommend changing them in pairs!! To compare two sensors that are in two different locations, I don't know a better way to do it but to remove them to see if they read the same ambient air temp. What am I missing?

[Healey Nut]

In the 14yrs that I have been working on the RTAA I have never seen a sensor off by a small amount . They are always way off , like out to lunch off , because the sensor has either shorted , grounded or is open . if you have a good infared or strap on sensor themometer or if its a refrigerant sensor use your gauges and work it backwards you shouldnt need to pull the sensor other than to replace it .

[Southern Mech]

In the 14yrs that I have been working on the RTAA I have never seen a sensor off by a small amount . They are always way off , like out to lunch off , because the sensor has either shorted , grounded or is open . if you have a good infared or strap on sensor themometer or if its a refrigerant sensor use your gauges and work it backwards you shouldnt need to pull the sensor other than to replace it .

Same here, never seen one off by a little, alway's way outa range. I have also never had an issue changing one. Pull it down to 2-3psig and good to go. I only had an issue with 1 water side sensor that the water valves were so rotted out they did not work. I took a bath on that for sure.

[mal_c]

Thermistor sensors such as Trane use in RTAA's can go out of range, especially the ones that are in cold spots such as leaving CHW: they suck in moisture sometimes which reduces the resitance and increases the temperature reading. I have only spent about six years on these things but agree with Graham: you shouldn't need to pull them out. You have two circuits: compare them. If your leaving chilled water is out you'll see that when you compare it to ent. CHW; you'll also likely get diags coming up telling you so. The RTAA is a great machine: don't knock them!

[werkinman]

RTAA is a good machine, I agree with above that they are usually way off if they are off at all and you shouldn't need to pull the sensors to check them.

[acjourneyman]

I have maybe changed a dozen in 18 years at Trane.

[ga1279]

I've also been heavily involved with RTAA.RTHA,RTHB and RTWA sensors and if they are way off it is easy to detect by using the charts. You may also have the alarm status letting you know whats going on with the temperature sensor. As a procedure during annuals if the sensor accuracy looks questionable (entering water a few degrees cooler then my thermometer comes out) the resistance of the sensor is checked. Another major problem I have come across is when a sensor (pair) has been changed the new cables are cut and then wire nutted to the existing terminations. I prefer to use the entire new sensor and remove the all the old wire along with the sensor, route the new cable as I'm removing the old and make a new termination in the amp plug on the control board. It really isn't that hard to do.-GEO

[Healey Nut]

Another major problem I have come across is when a sensor (pair) has been changed the new cables are cut and then wire nutted to the existing terminations. I prefer to use the entire new sensor and remove the all the old wire along with the sensor, route the new cable as I'm removing the old and make a new termination in the amp plug on the control board. It really isn't that hard to do.-GEO


Thats the way its supposed to be done but there are a lot of hacks and lazy @&?holes out there that think they know better !!!!!!!!!!!!!!!!!!
And its guys like us that do it right that have to fix their #@?$ work !!!!!

[jayguy]

...As a procedure during annuals if the sensor accuracy looks questionable (entering water a few degrees cooler then my thermometer comes out) the resistance of the sensor is checked...

i, too, used to check the resistance on suspect sensors, but i never found one that was inaccurate at the control panel! the resistance ALWAYS matched the chart and the resistance chart ALWAYS matched the control panel...but the resistance RARELY matched the actual!

[BKS60]

Just replaced a saturated condensor sensor last week and I have to agree with graham.

Pulled the old wiring out and rewire tied back to the control board. I have seen a few with those blue wirenuts at the sensors and I just cannot remember ever seeing a new unit show up that way.

Maybe its a little overkill but I cut out the old ties and use the mounts for the new ties. I just like the equipment to be neat and clean.

[jemawalton]

The biggest problem I have with these sensors are the wiring connections on the board. I hate those connectors. A poor connection here will give you strange readings.

[ga1279]

Graham, Jayguy and Jemawalton: I know what the bulletins and service books say about sensor change, but I would rather have a solid insulated wire from the end of the sensor to terminate at the proper module. The termination isn't really that hard to do, I use a small c-clamp vise and mount the MTA in there and I use the rounded lead from an old Fluke test lead and it will pop it right in there correctly. Then again you could be real fancy and spend the money for the AMP tool, but unfortunately I can't afford it as little as I replace them. I have had several that the blue or orange wire nuts had gotten corroded inside and increase the resistance and made a good sensor look bad, thus the reason I follow the procedure I outlined. I like running them the same length as the original. Except for the larger units that have the junction box at mid point along with the condenser fans. There is generally enough wire to go from the evaporator liquid point to the module. I have also seen those beads not positioned correctly and causing a variance on the reading. I like to leave the machine better then it was when I got there. -GEO

[SanchezHVAC]

Am I the only one who shakes my head when I have to pull a sensor to check accuracy? Why doesn't Trane use wells for the sensors?


Thats what that fancy chart in the IOM is for , you know the one that compares resistance to temperature ??????????

What page is that chart on? Do you have that IOM?

[Sserrviceman]

RLC-SVD03A-EN manual pages 15-18, RTAA-SB-5 service bulletin pages 19-23.
RLC-SVD03A - http://www.graycoolingman.com/upload...-svd03a-en.pdf

[Haris Shahid]

Hi sir can you told me the size of oil drain valve of oil separator of RTAA 328

[71CHOPS]

Hi sir can you told me the size of oil drain valve of oil separator of RTAA 328

instead of reviving a 10 year old thread with a topic that is completely unrelated to your question, start a new thread for your issue. you will have a better chance of getting an answer.