Installing new condensing unit, 4t heat pump to replace old r22, evap ok?

[Backyardactech]

I won't get into the question of whether or not the original evaporator can "handle the higher pressures of an R410a environment," my question is about the metering device on the existing coil.

The customer has a burnt out compressor on her existing r22 heat pump split system. She wants to go with a new condensing unit because of the age on this one, so I worked her up a price for a new 410a heat pump with replacement coil and line sets as well as a TXV to keep the unit 13SEER. Now she's telling me she had another quote that would use her existing a-coil (since it was replaced fairly recently), they would change the condensing unit, and just add a TXV to handle the 410.

The metering device she currently has on her coil appears to be a fixed orifice with distribution tubes going into the coil.. how can you replace this with a TXV?

[al]

Cut out the fixed orifice and fit an externally equalised TXV, keep outlet pipe from old metering device to attach to TXV.

Alternative is to use an inverter outdoor unit, say Mitsubishi, comes with a kit to use with an AHU, have used these on old R22 evaporator AHU's, work really well and fairly silent compared to condensing units.

Also using the Mitsubishi allows the unit to flush the old mineral oil and store it in the unit.

al