Hot water recirc system not working

When the pump is running the pump and piping around the pump will get hot even if there is no water flow. Check the spring loaded check valve, that brass thing between the pump and the water heater to make sure that it's arrow is pointing down also. more possible problems; 1) The pump may not have enough "head" to push water through that spring loaded check. If that is the case, remove it and replace it with a standard swing check in the horizontal piping above the pump. 2) The pump may be air bound and will require that a vent valve be installed in the horizontal piping above the pump to purge the air. That type pump will not push any trapped air in the pipe. The air stays trapped and the pump will not pump. The installation looks OK except for the spring loaded check and the pipe above the pump not having a vent valve. I have the same pump on my hot water recirculating lines that handles 3 bathrooms and it works great. I set my timer to run the pump 15 minutes each hour and for 2 hours in the morning and evening when we normally take showers. my 2 cents

It appears that the pump was installed without unions on both ends. The bottom connections appear to be threaded and the top return pipes are soldered. The vertical installation requires special low melting point solder and the body to be wrapped with a wet rag and not to over solder. The installer may have damaged the impeller during installation when soldering. The other cause of failure as noted by @d.george is the system has to be completed vented of air at the highest point. This is the instructions from the installation guide, "Do not start pump until the system has been filled and vented. Air should be vented from the system by means of an air vent located at a high point in the system. The system must be completely vented prior to pump operation." –