I have 10 hir handler and 13 seer heat pump. My hvac guy used a expanion valve to make the two work. But he said the suction should be 60 or 70 psi, but its not. What could be the problem? Or could this hurt my new heat pump?

The inside coil is not large enough. It will work but not properly. Always change the inside coil to match the outside unit.

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https://www.askmehelpdesk.com/heating-air-conditioning/danger-mismatched-c-seers-outside-inside-exchanger-205726.html#post989592