Trane system not working after replacement TXV


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Old 07-21-18, 09:57 AM
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Trane system not working after replacement TXV

Hi All,

Need some advice on what to do next.
I have a house that is cooled by 3 systems (downstair Main, Downstair Bedroom, and Upstairs Bedrooms). We have had issues with the downstairs main system not being able to get down past 76 so I called an AC company, They tried to top up with 410 and their gauges went crazy so they said it needed a new TXV. We had the TXV replaced and now the system will not cool beyond 78.

They told me that all the readings are good (see below / attached) and they have no idea whats wrong with the system. Any suggestions?

My AC bill has also almost doubled in the past 3 months, It hot in Texas but this beats past years when temps were also as high.

To make things worse my upstairs system is also behaving strange (it is not cooling to were we want and last night my downstairs bedroom system stopped working which appears to be a capacitor issue).

Any advice would be great.
 

Last edited by PJmax; 07-21-18 at 10:28 AM. Reason: removed images of pressure readings
  #2  
Old 07-21-18, 10:31 AM
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Welcome to the forums.

Unfortunately the DIY administrators do not allow us to discuss pressures or charging methods of residential A/C equipment.

air-conditioning-cooling-systems/315401-charging-your-A/C

I'll make one comment: Those pressures look way too high. Call another HVAC company.
 
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Old 07-21-18, 12:17 PM
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I spoke to another HVAC services and he said the pressure is a little high however we are experiencing 110 temps with lows of 90s so he said hard to really test everything as systems are struggling in general with the heat.

on my other bedroom HVAC I replaced the capacitor, the old one was definitely dead, however Iím still not getting the system to turn on. If I depress the contractor and hold it there the fan motor starts up. I have switched of main system and restarted to see if that help but no luck.

any thoughts on either??

it hot and the worse time for all 3 systems to play up
 
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Old 07-21-18, 12:32 PM
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On the system that you changed the capacitor on, if the contactor isn't coming on, you're missing the 24VAC control voltage across the contactor coil. This could be caused by any number of problems: blown fuse in 24VAC line, bad thermostat, broken wires/cable from house to outside unit, low pressure switch is activated, high pressure switch tripped.

If you have a multimeter, I would start in the house. Remove the thermostat from it's backplate and measure the voltage between the R and Y terminals. You should measure 24VAC. If you do, your transformer and fuse are good. Put the thermostat back on and set it to Cool. Check the voltage again between R & Y. It should now be 0V. If so, your thermostat is good.

Next, go outside and check for 24VAC where the cable coming from the house attaches to the outside unit with wire nuts. If you have 24VAC there, everything is good out to the outside unit. Check to see if you have 24VAC across the contactor coil (usually the side terminals). If you measure 0V there, either your low pressure switch or high pressure switch has opened. Note that not all systems have high and/or low pressure switches. If you have a high pressure, it will have a reset button (usually red) on it. Try resetting it.
 
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Old 07-21-18, 12:58 PM
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Thanks Bob

i need to get a multimeter from a friend and will give go through steps outlined.

thanks and we provide an updated in a while
 
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Old 07-21-18, 01:55 PM
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Looks like the issue after replacing the capacitor was me being inpatient- it was simply the 5 minute thermostats delay to protect the compressor.

Now I just need to work out how best to resolve the other 2 Units.
 
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Old 07-21-18, 02:53 PM
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Glad to hear it was simple.
 
 

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