HVAC Guys, a little help please.

[threewood]

Dealing with a high pressure shutoff. This is a 3.5t Armstrong heat pump. Air filters are brand new, evap coil has just been cleaned, although it wasn't dirty. Plenty of airflow through the return.

Cool mode works fine, kicks on and kicks off when temp is hit. Screen shot of numbers below

Heat mode is a **** show. Head pressure continues to rise into the 500psi before it cuts off. Suction rises as well. The air handler has a piston orifice. Which should be for cool mode. Once heat mode is commanded, it switches to a txv on the condenser side. I'm leaning toward a bad txv valve. Is it possible for a piston orifice to stick in the housing? Another possibility for overpressure?
Heat mode...

 

[threewood]

You can see the temp on the discharge get to 146° which I don't think is normal.

 

[threewood]

Pulled 5lbs of r410a out and head pressure is still at 500.

 

[5.7 hemi]

Is the fan moving? No airflow would cause the high side pressure to go up. But I’m not a hvac guy.

 

[threewood]

Is the fan moving? No airflow would cause the high side pressure to go up. But I’m not a hvac guy.

Yep. Outdoor fan is going. Indoor fan is going. Oth coils are clean. It's got good air flow. No problems in cool. Only have issues in heat, where the flow is reversed.

 

[5.7 hemi]

Well, I’m no more help to ya.

 

[threewood]

I'm going to evacuate the system and check out both the piston orifice and thermal expansion valve. It's got to be one or the other.