I have installed a new pump. Still getting no water from head or steam

Ran the unit for first time in years. Took apart boiler all looks clean. Replaced pump with a new unit from Amazon. It made all the right noises, but was not getting any water from head or steam from wand. It seemed that water and steam was all going back into tank. To test that pump indeed worked, I have removed the boiler valve retaining nut, spring and nipple. Ran unit. Water flowed out with no problems. Cleaned and reinstalled spring, nipple, nut. Still not working. Is it just a bad spring/nipple that's causing the head to not open? I have also removed the wand tip and cleaned it. Still not working ? Any help in solving these two issue is greatly appreciated. Thanks so much.