Weird HVAC problem - Need advice

[Nickshu]

The short cycling is an interesting thought. I know it's a modern Honeywell thermostat that has a recovery mode between cycling so that many not be possible?

Today we lowered the max blower speed to see what happens. That was Trane tech support's only idea to try. Will see if it starts draining at all.



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[cabmandone]

If you're dropping the fan speed I'd probably watch your suction temp for a little while to make sure you don't frost the coil due to inadequate air flow. I'd think as long as you went from High speed to either medium high or medium (assuming 4 speed blower) You should be fine.

Just out of curiosity, what is the A/C size? 1.5-2 ton?

[asphaltgambler]

To add - as your OP - this situation is a recent development, there is something new that's going on.

[Nickshu]

Update - Basically everything you guys have suggested above has now been checked out by my HVAC guy (thanks for the recommendations, I passed them along) and it is all showing normal.

He did get in touch with the next level of tech support at Trane (engineers) who recommended he look at the TXV valve. They asked for some data off the unit and he took readings today and forwarded it to them, waiting to hear back. Replacing the TXV may require us to upgrade the unit to R-410 from current R-22, if that turns out to be recommended.

[cabmandone]

Normally a faulty TXV will show up in operating pressures. I'll be surprised if it's a bad txv.

[asphaltgambler]

Agree^^^^^^ that's the whole point of throttling back the high pressure gas to low pressure liquid. So if that delta between high side coming in and low side remains in range, the evap has to be almost ice. The tech needs to let the system run with gauges/ probe connected for 15- 20 mins to make sure the TXV remains constant in pressure differential.

My recent situation proved this out as initial cycle would be fine, then the low pressure side would start falling off after 20mins or so

[cabmandone]

BTW, a new txv shouldn't necessitate switching to R410. I recently did a txv swap on a 25 year old Carrier R22 system. You can still find the R22 txv's it's just a matter of pulling the part number off the existing txv and doing an online search or talking to a parts supplier who can cross reference the old number. It might require some new piping depending on how the old txv is connected in the system but it can be done.