A: It have NSF 51 listing.
A: Not if the water in the tube will be under pressure. You can used standard 1/2" pex for that which has the same inner and outer diamters.
A: No, this tubing is not rated for use in hot water applications.
A: I checked the manual for the pump and it doesn’t say what tube size for the 4000 series. I would just purchase the tube after you determine what size it is and what fittings you need
A: should be ok using low pressure
A: Under 175F, the tube is safe but I would not drink hot water that goes through this tube
A: Working pressure -40 to 175 F. Thanks.