The error file suggests that one of the reason for this problem could be pump heat building up over time. Hot water loop has the constant speed pump with constant control type. This means the pump is running all the time. Also, Rated Flow Rate and Rated Power Consumption are autosized and Rated Pump Head is specified. I used the default pump head with intermittent control type and the file ran to completion. Sending you the modified file in case it helps.