The plumbers installed the PEX, manifolds and pumps. The HVAC contractor installed the conenctions from the Triangle Tube PE110NG to the pumps. The pumps are on the return pipes pumping water from the PEX to the boiler rather than on the Supply side. Most designs I see always have the pump on the supply side drawing water from the boiler to the PEX. My HVAC contractor says that it's better to be on the supply side.
The problem I ran into and not sure if it's at all related since the circuit is a loop anyway and it seems the boilder controls whether water flows through it or not...
We were running water to wash dishes, the dishwasher and filling a tub for bath and the hot water ran out. I went down to the boiler to see what was up and it was flashing a soft lockout code (b 30) which was "temperature difference between the supply and return is more than 72F. Burner will remain OFF for 150 seconds). The boiler temp was 186F on the supply and only 102F at the return. The DHW was at 60F. Every time the boiler tried to fire up to heat the DHW when the supply dropped low enough to do so, the supply temp would increase so quickly that it would lockout (b 30) after a few seconds.
I tried to run the heat to get the supply temps down but the boiler wasn't letting any hot water to circulate. I ended up releasing water via the pressure relief valve which lowered the supply temps enough to let the boiler run it's normal course.
Is this a setup problem or do we need to ensure that we don't run out of DHW and wind up in a lockout situation? Should I be calling my HVAC guy back to fix something or just be more conscious when using DHW?