high side fluctuates on 3ton 16seer 410 a/c

[rnsphcc]

I have a new Goodman SSX16036 3Ton 410A Condeser and A/coil and line set on a new GMH95070 furnace for a 1850 sf home. Old unit was a 70000 BTU 70% AFE with a 3ton A/C 10 SEER the new unit Is not cooling the house below 73 Thermostat set at 68 for two days. Out side temperature is 85F with a 70% humidity unit. Set gauges on new unit and the liquid- high side fluctuates from 300 to 400 psi and the suction side temperature read at the gauge 48F and the temperature at the suction line is 48F and the temperature coming out of the register is 52F. Why is the high side is fluctuating Can it be overcharge from factory? or there is something else I'm missing I can use some help Thanks

[nike123]

Condenser fans maybe have some regulation?

[Brian_UK]

What is the length of the line set between the condenser and the A-coil?

Was the base gas charge adjusted to suit the length after installation and evacuation?

[monkey spanners]

Do these need an aditional charge to be added based on subcooling? assuming a txv which i would expect nowadays.
There is often a chart on the outdoor unit panel or such for the right subcooling depending on ambient temps (based on comissioning vids i've seen, we don't have that style of equipment in the uk)

Jon

[rnsphcc]

Brian-UK
line set are 20' long and I was told the condenser was pre-charge up to 25' long line set. That why I dint add any charge. thanks for your help

[Brian_UK]

Not trying to teach you to suck eggs but seeing your Bio states "Plumbing" were the lines tested and evacuated before the valves were opened?

[billdozza]

First of all 3 tons for a 1850 sq ft home is to small

[nike123]

First of all 3 tons for a 1850 sq ft home is to small

To say that you need to know how good (bad) is home insulated, infiltration, etc... and if all that space is conditioned.
Rule of thumb is rule of thumb. Nothing more.