The last test setup I did was a program involving our energy provider.
I wasn't to satisfied.
Honestly, the issues you have aren't something requiring extreme testing equipment, or some special government test.
Just the normal tools on a service truck.
To prove my point about the inaccuracy of government tests:
AHRI recently bumped all high efficiency boilers down to 90% (from 95%), because there was a flaw in the DOE's testing criteria, and required all high efficiency boilers to be retested at their new standard.
I hope this is not to far off topic. I was at a class today and "Check Me" came up. The instructor said that because of complaints to the state a spot check of all the installs where a check me was performed, 85% failed the spot check. The implications are that most people as falsifying the data. So I would be suspect of the any "Check Me" reports.
As far as the varying pressures, could it be possible that the airflow is varying because the fan speed is varying?
My experience with mobile homes is that the duct work is almost always too small for heat pumps. My guess would be air flow. Either fan malfunction or undersized duct. Most likely undersized duct.:.02:
That gooman blower section has 0 tech specs on airflow....the coil might and an experiment could be run on the pressure drop across it.
Might only drop off 2% per .1" above .3", or it could be a non linear drop off, and lose 15% air flow at .6"ESP. How much it drops off is directly related to what RPM they need to move that rated CFM at .3", the higher RPM they need at .3", the more it drops off with even a small increase in ESP.
Nordyne also rates their blowers at a low ESP, and they drop off pretty quick as the static increases.
Pretty sure that blower is rated to move its X CFM at .3" not including the coil PD. So the return static readings that were taken are pretty useless. Most modular blowers don't include the coil, since they don't know what coil will be matched to it.
But to diagnose the OP's problem we need to know how much air he's moving across the coil & his static readings don't tell us that.
Knowing all the dip switch settings would be very useful. If he's set up for 2000 cfm then we would expect very high static & if set for 1000 cfm very low static.
Does this blower section have electric heat to do a measurement?
As long as coil is spotless.
Well two months later an update on my problem heatpump. Goodman had a troubleshooter on the phone and we remeasured the static pressures under her guiedence with a new instrument and a different person --- the pressures were exactly the same as previously stated! So air flow was off the table. After changing the refergerant charge and repeated testing the trouble shooter gave up and refered the problem to the engineering dept. Their solution was to test the A coil for any blockages and then finally replace the "compensator" !!! This is what my first expert suggested and it was the most obvious thing to me. We did this yesterday and it has cured the problem. The high side in heat mode is down and the low side is no longer "searching" -- just nice steady pressures well within the expeced range. So we hope the problem is solved! Thanks to all of you that gave thoughtfull replies and to all those who just insulted me -- maybe you can learn something, but probably not.
I did not read all the posts so don't know if the heat pump refrigerant charge compensator was adequately explained.
Here is a diagram & explanation: The Heat Pump Compensator