RMS-MF 2018 with 12/20 Addenda

Companion Guidance—Section E-4 AARST Informational CG 10 Companion Guidance RMS- MF 2018 Non-ASD—Example HVAC Diagnostic/Repair Checklist Comprehensive HVAC System Diagnostic/Repair Checklist This table may be helpful during pre-mitigation evaluations or post mitigation inspections associated with a “Long-Term Operation, Maintenance and Monitoring Plan”. 1. OUTDOOR AIR INTAKES OBSTRUCTIONS: Ensure outdoor air intakes are clear of obstructions, debris, clogs, or covers. POLLUTANT SOURCES: Resolve any problems with pollutant sources located near outdoor intakes. AIRFLOW: Confirm that outdoor air is entering the intake appropriately. 2. SYSTEM CLEANLINESS AIR FILTERS: Replace filters per maintenance schedule. 3. CONTROLS FOR OUTDOOR AIR SUPPLY Ensure that air dampers are at least partially open (minimum position). Ensure that minimum position provides adequate outdoor air for occupants . CONTROLS INFORMATION Obtain and review all design inside/outside temperature and humidity requirements, controls specifications, as-built mechanical drawings, and controls operations manuals (often uniquely designed). CLOCKS, TIMERS, SWITCHES Ensure summer-winter switches are set the correct position with time clocks set appropriately. Ensure that settings fit the actual schedule of building use (including night/weekend use) . CONTROL COMPONENTS Ensure all controls and sensors are functional at both the occupied (day) and the un occupied (night) settings. This includes checking line pressure for pneumatic controls under both conditions. OUTDOOR AIR DAMPERS: Ensure the outdoor air damper fully closes within a few minutes of shutting off the air handler and opens (at least partially with no delay) when the air handler is turned on. • In heating mode, the outdoor air damper should go to its minimum position (without completely closing) when the room thermostat is set to 85°F. • In cooling mode, the outdoor air damper should go to its minimum position (without completely closing) when the room thermostat is set to 60°F and mixed air thermostat is set to 45°F. FREEZE STATS: A RADON MITIGATION CONCERN: Freeze-stats close the outdoor air damper and disconnect the supply of outdoor air when tripped. They trip intentionally when the outdoor temperature range is 35 ° F to 42 ° F to protect water coils within HVAC units from the cold. As a result, mitigation systems based upon pressurization or dilution can fail during the time periods of freezing outdoor temperatures or Freeze-stat failure. For general maintenance, confirm that any freeze stats are functional as designed. MIXED AIR THERMOSTATS: Ensure that the mixed air stat for heating mode is set no higher than 65°F and for cooling mode, it is set no lower than the room thermostat setting. ECONOMIZERS: A RADON MITIGATION CONCERN: Economizer systems vary the amounts of cool outdoor air supplied to the building to assist with the cooling load of the room or rooms. Either in failure mode or as designed, unless economizer systems leave dampers adequately open for meeting minimum mitigation requirements, mitigation systems based upon pressurization or dilution are likely to fail during the time periods of either high or low outdoor temperatures and including times of high humidity. There are two types of economizers, dry-bulb and enthalpy. The dry-bulb is typically set at 65 ° F or lower. Dry-bulb economizers vary the amount of outdoor air based on outdoor temperature, and enthalpy