I had a HVAC specialist (with a refrigeration license) tell me that he can not accurately determine the amount of R410 to put into my heat pump system because it was too cold. The ambient temperature was affecting the accuracy of his pressure measurements and he can not get any R410 out of his pink canister. He asked to come back when it was at least 50F outside.
Is this possible? I am assuming that there is a way a rounded this "problem" otherwise no heat pumps would be installed (or sold) during winter.