I just finished installing a tankless water heater (yay!). Unfortunately, we weren't ready to do a full replumb of the house, so we patched into the pipes connecting the old water heater. For some reason, this house has galvanized plumbing for everything (gas and water). Before replacing the water heater, all water ran as expected. Afterward, I believe we dislodged some of the built-up deposits and now the sink faucet is running slowly.
Is there a good way of dislodging corrosion build-up within galvanized? We'll replumb soon, but having full functionality until then would be nice.
EDIT: Additional information: The hot and cold do not get mixed at the faucet, like a typical faucet. Instead, there are two faucets, one for each the hot and cold. As such, backflushing will take a bit more effort.
Also, I've tried leaving a hot faucet open and closing the tankless hot service valve (effectively closing the hot supply), then switching the service valve back on in an attempt to create a water hammer effect. This did not work after several attempts.