So the tech came out, but I am not happy...

[mark johnson]

The tech came out to charge the system, but did not do what I expected. I expected him to charge it by SH and SC numbers, as was suggested here.

Instead, he added some R410A, checked the pressures, and the temp drop across coil. He said that the suction pressure was a bit high, but "OK", and that since the temp drop across coil was "fine" (20F), that all was fine. He didn't measure SC or SH.

Here are the numbers he got: liquid press: 300, suction press: 130. After he left, I measured the liquid line temp at around 84F.

The suction pressure seems very high, I don't even see such a high value in the tables. Is that right?

If I understand SC, then at 300 psi and 84F liquid line temp, that's about 13F SC, which seems higher than Goodman's recommendation of 5-7F...

Should I accept that the temp across the coil is all that matters, or do I need to call them back out?

Mark

[tunnel_rat]

410 pressures are higher than 22. Those pressures "look" about average.
Why was he charging the system to begin with? Leaking?

[mark johnson]

Sorry, I should have mentioned this - this is a brand new system, so he was doing the system startup. The Goodman instructions do not even list suction pressures above 80 psig, so the 130 that he measured seemed way high to me. So this seems OK to you?

[DPSwitch]

No suction pressure above 80 listed on a 410a unit?

Interesting.

[tunnel_rat]

Are you sure it is a 410 system? Not R-22? 130 is not high for a 410 system.

[forcryinoutloud]

Sorry, I should have mentioned this - this is a brand new system, so he was doing the system startup. The Goodman instructions do not even list suction pressures above 80 psig, so the 130 that he measured seemed way high to me. So this seems OK to you?

Something is not right here, the Goodman chart should show a higher suction pressure than 80 psig, at 80 psig R410a is only at 21* F, which is way low.

What you're saying is making no sense. Are you sure it is a 410 system?

[RyanHughes]

Model # of the outdoor unit?

[tunnel_rat]

No suction pressure above 80 listed on a 410a unit?

Interesting.

He did say it was a Goodm......oh never mind....

[udarrell]

R410A, at 130-psig Suction temp is 45-F.
If Goodman says 5-7-F SC, then that is what it should be.
However, it seems that extra heavy load conditions could raise the listed SC figures. Do they list any temp perimeters?

Guess most of them don't know to do it the way we do it. Goodman should have the charge technique laid out for the techs, if they follow it they will be okay.

What is far worse, I witnessed a local guy here do a R-22 charge check on a TXV system, all he did was check the suction pressure & said, suction is okay, unit's charge is okay!

Of course, that is NOT a check for proper charge on either type of metering device! He figured he had done his job the right way. WOW! - Darrell

[papa_jo]

see chit like that all the time down here- go figure--- well-at least I get some calls from
this but it sure makes the industy look like chit

[mark johnson]

The outdoor unit is a SSX160601, 2 stage R410A, with TXV at evaporator.

Maybe I am looking at the wrong thing, but I am looking at the table they show in the installation instructions, top of Page 6, on the left.

Is that not the right table to look at?

So do the numbers I quoted earlier seem right, and I shouldn't worry about it?

[beenthere]

At 300 PSIG, and 84° line temp, you have just under 12° SC.
As earlier, R410A at 130 PSIG is 45°F, 80 PSIG would be 21°F, so I don't know what chart your looking at.

80PSIG, would be more inline for R22.

Post the model numbers of your equipment.

[forcryinoutloud]

According to the manufacturers charging instructions and only knowing your subcool reading, the system is NOT properly charged. Would like to know what the superheat readings were at that time since Goodman specs specific superheat and subcool readings in their charging instructions.

Don't know why Goodmans chart doesn't show higher than 80 psig for 410, maybe they were trying to save on ink and paper.