4 way valve testing question

[bradley wayne]

Hi everyone,
Getting some mixed messages on 4 way valve testing. What is generally acceptable on the temp pass through? I was always told 3 degrees?

Today I had one that was losing 20 degress on the high side pass thru, 199 to 179. But the low side was right on the money. No temp increase. So where did this 20 degress of heat go?

On this same unit the TXV that is on the indoor coil is blocked, it shoud allow free flow in heat mode but it is major blocked. Losing 40 degress across the txv (80-40). Im talking about the TXV that meters in AC mode but should not in heat mode. Maybe this has something to do with the 4 way problem because it has my pressures down to nothing. Im going to change the TXV and then double check the 4 way. Just seems strange.

Thanks for any advice

[beenthere]

Can't check a RV if a TXV is restricting.

[Kevin O'Neill]

I was always told 5 degrees.

[prorefco]

The temp difference you get depends on whether you're in heating or A/C and what loading you have. If in A/C mode at near full load, I would think you should see less than 1ºF difference on the suction side and maybe up to 3 degrees on the discharge side if that....

[openclasspro]

I was always told 5 degrees.

ditto - threshhold of most mfg ratings