This might be a dumb question but would appreciate any knowledgeable answer besides "why don't you just try it" 
I will be replacing my pool heater. There is a bypass valve and associate plumbing to bypass heater but the heater outlet (return, hot side) is 'blocked' by a check valve not a diverter or similar valve. The attached picture is not my actual setup but plumbing is the same. Can I just remove the heater and run the pump in bypass mode without connecting anything to what will be a 'hanging' (unconnected) side of the check valve or do I need to put an end cap on temporarily until the new heater is put in place? I guess the equivalent question is does the 'inlet' side of a check valve have to have some minimum pressure for the check valve to work in the 'blocking' direction. Thanks for any answer.
I will be replacing my pool heater. There is a bypass valve and associate plumbing to bypass heater but the heater outlet (return, hot side) is 'blocked' by a check valve not a diverter or similar valve. The attached picture is not my actual setup but plumbing is the same. Can I just remove the heater and run the pump in bypass mode without connecting anything to what will be a 'hanging' (unconnected) side of the check valve or do I need to put an end cap on temporarily until the new heater is put in place? I guess the equivalent question is does the 'inlet' side of a check valve have to have some minimum pressure for the check valve to work in the 'blocking' direction. Thanks for any answer.
