I notice this pump as with most these days has a thermal cutout -It is likely no damage has been done to the motor but a strip is necessary I suggest.
Before anything try the center screw on the pump ,turn it to 6M head and try -it may be that whatever circuitry they have in there is corroded or kaput and it may work on the 3M or 6M setting.
As far as water flow, its probable that little water will flow out if you can stop the air getting into the tank while you are checking the pump. with the upturned tube and fittings below the pump air will not be sucked in and therefore water cannot flow out as long as no water can get into the tank from the top while you are doing this -Think about it -Like an upturned beer bottle full of water in a dish full of water. Until the dish level falls to allow air to enter no water can flow out.
That said though the non -return valve above would allow air in .If it is an isolation valve as mentioned then make sure it is off.
https://www.sydneytools.com.au/shopexd.asp?id=9980&bc=no
$228 for a new pump is good news hey?
Heres some specs of the pump
Liquid:
Max. operating water temperature:80 deg C
Temperature:Class 110
Materials:
Pump body:Bronze, DR
Back Plate and Rotor Can:Stainless Steel
Impeller
PO
Installation:
Maximum ambient temperature:40 deg C
Maximum operating pressure10 bar
Port Spacing:150 mm
Pipe connections suction/discharge:1-1/4” BSP M
Optional Union Set:1-1/4” BSP F/3/4” BSP F
Electrical data:
Rated voltage:240V
Mains frequency:50 Hz
Current Max:0.4 amps
Capacitor:3 uF
Power consumption speeds 1,2,3 46W, 67W, 100W
Motor duty:Continuous
Motor type:Canned rotor
Motor protection:In-built thermal overload
Ingress protection:IP 42
Insulation class:F
Power cable length: 1.2 m
Net weight:4.0 kg