New to the forum and first post.

Last Fall I had the old VHE boiler removed and a new system with a Burnham Alpine 150 installed.
I have come to realize my plumber has no idea on how to set up this new type of boiler.
When the cold weather hit we could not keep the house warm. His suggestion was to install additional heat under the sink area in the kitchen. I told him that we never had a heat problem with the old system and this boiler you recommended has a higher BTU rating. Long story, but the short of it is with manual in hand, a stool I spent several hours in the basement monitoering the operation. It soon became aparent that it was short cycling and shutting down due to a temp overshoot when it fired up. I reset the factory overshoot of 2deg to 10 and that helped a bunch.
My question now is what effect does the boiler pump speed have on the system? I am bumping of the low limit much/most of the time now that temps are in the upper 30's, and the return D/T is less than 3or4 deg much of the time.

Thanks for any help.

Cape Cod