Thank you for allowing me to assist you, my name is Joe and I will be happy to assist you with your concern today.
Broken pieces will go downstream following flow, this means heat exchanger, hoses, etc. These will clog a heat exchanger. If somehow they can make it then they can make it to the exhaust be it manifolds, risers etc.
If there are pieces missing then you will need to inspect the entire raw water side of the system and locate any that are lodged and remove them all.
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