adding more expansion

I need to add a larger expansion tank at my oil boiler. the existing set up uses a 1"1/4 to 1/2" tee to the tank . The new tank has a 1" connection. Can I run a few feet of 1/2" to the new tank or do I have to run 1" from the 1 1/4" ?

1/2" is fine - you don't have much actual flow through that pipe, so the flow resistance of the 1/2" is negligible.

Joe

thank you Joe ! scott