Performed heating pm on both RTUs. Found unit 1 belt broken and system locked out. Replaced belts with new in both units. Replaced filters. Flushed out drains. Inspected cleanliness of blowers and coils. Inspected both heat exchangers, good no rust. Checked capacitors and contactors. Tightened electrical connections. Ran heat. Measured amp draw of inducers and blowers. Measured heat rise and checked safeties. Both units are operating normal at this time.