Seemingly wrong PT relationship

Hi.

I have this 28 oz can of r410a at room temperature of 77F.
When I connect a gauge to it, I measure 258 psig.
The r410a PT chart says I should have 226 psig at 77F.

What am I missing?

Thanks.

The compariter - PT chart is correct so.

Either

Your gauge
Your thermomiter
or
The refrigerant is out.

If you thermomiter and gauge is ok you do not have R410A.

410 is a Zeotrope and it will fractionise (seperate) if it has had a
leak in the past or if the thing was vented.

I personaly would check my gauges and thermomiter for accuracy.

Regards

Rob

.

Did you measure the vapour or liquid temperature?

I measured the liquid temp, because I put my probe below the line. That is, as far as I can guess where the line is inside an opage can filled at 80% capacity.

Thanks all for your time.