Your old pump will typically have had been 1/20hp and 88watt with 3/4" OD barb fittings. Typical Model Numbers: SM-959-NHW-14 thru SM-959-NHW-26. (Note that older models of this circulation pump may also have a motor capacitor mounted on the outside of it).

Brand: Laing
Type: Circulation Pump
Set Includes: E10 Pump
Frame Material: Thermoplastic
Material: Metal
Model: E10
MPN: 605000116
Item Height: 125mm
Item Length: 154mm
Item Width: 105mm
Features: less than 40 db
Lining Material: Metal
Manufacturer Warranty: 12 months