Troubleshooting with Rheem Tankless Water Heater & Grundfos Alpha recirculating pump

erikshouse

I'm in a new construction home that had this whole system installed as part of the homes standard features. It's a 1 year old Rheem tankless water heater, and a Grundfos Alpha recirculating pump on a closed loop. For a year or so, everything was working perfect. But lately the hot water taps are not triggering the tankless heater when opened up, giving me no hot water. It happens pretty erratically, but lately more consistently. I tested it without the recirc pump for a few days, and the tankless worked fine.. except that it takes 2-3 minutes for hot water to get to the tap. Is there a recommended setting on my recirc pump or temp setting on my tankless heater. (its currently 130º). My pump has 7 settings. 3 speed and 3 pressure settings, and an Auto/Adapt setting. It's always been on Auto Adapt.


I have already flushed my tankless system with white vinegar and cleaned out the filter. I've also put in new aerators on alot of the faucets, and cleaned most of the others. The water pressure is fine and the water is coming out of the taps fine. I'm totally at a loss.. The biggest thing confusing me is that it worked great for a year, and now it's not.