This checklist was designed to help aid in a smooth building walkthrough when conducting a retro-commissioning pre-inspection:
Energy
Who is the energy provider?
Do they offer interval data tracking through your meters?
What is the fastest interval they track at? 60 minutes? 15 minutes?
What rate/tariff is the facility on?
Can we obtain the itemized energy bill?
Heating
Locate all heating equipment and note the types (AHU, VAV, Reheat, DOAS, etc.)
What spaces do they serve?
Are there any dampers used for controlling airflow?
Note how they are performing. Are they open or closed at this time?
Is there an outside air damper?
What’s the condition of that damper?
Is this an economizer?
If so, how are the return air dampers?
Are there any filters with this unit?
When was the last time they were replaced?
Are there heating/cooling coils to the air handler?
If so, are they working correctly? (A temperature gun or thermocouple is great for determining the temp)
If not, where is your heating source? VAV boxes? Terminal reheat boxes? Etc.
Boiler (Optional – Commercial)
What kind of boiler is it? (Condensing, etc)
Note equipment specs and sizing criteria.
Primary/Secondary or just Primary water loop? (aka How many pumps does it have)
What is the operation of the boiler right now? (On or Off, fire rate, sound, etc.)
What controls the boiler? (Static Pressure, Return Temp, Supply Temp, etc.)
How old is the boiler?
Is it oversized or undersized?
Cooling
What types of cooling does your building have? (Chiller, compressed refrigeration, forced air cooling, evaporative cooling, etc.)
Do you have the ability to “step down” your cooling? (Does your air handler have multiple stages or is it single stage?)
What controls your cooling equipment? (DP, RA Temp, SA Temp, etc)
Is there demand ventilation? (CO2 sensor or hand switch in the space?)
Are your control points in the right location for control of the system?
Chiller (Optional – Commercial)
Note sizing criteria and equipment specs.
How old is the chiller?
What controls the chiller? (Supply Temp, Return Temp, DP, etc.)
When was the chiller’s maintenance performed last?
Primary/Secondary loop or primary only?
Expansion tank?
Heat exchangers?
If so, when was the last time the heat exchangers were flushed?
Domestic HW
How often does the HW heater cycle on and off?
Tank type or instantaneous?
Note sizing criteria and equipment specs.
Holding tank?
Primary/Secondary or only Primary HW loop?
Expansion tank?
How many gallons (approx.) is in the loop?
Propane/Natural Gas/Electric water heater?
What controls DHW pump?
VFD on pump? Or Constant volume?
Are there circuit setters in the loop?
Controls
What controls are in place?
What do they control? Which components?
What do you WANT them to control?
Are there any run-time monitoring capabilities within the control system?
Are your control points (static pressure, temperature, etc) placed in the correct place? (RA duct, SA duct, etc)
Are the control components correctly calibrated?
Has the building ever been commissioned professionally, or re-commissioned?
Takeaways
You should always check the status of your equipment, how old it is, what maintenance is performed, how it controls the building and what spaces it controls.
System diagrams are an integral part of the retro-commissioning process, because without knowing what/where/why a system operates the way it does, comes down to understanding systemic flow (Air, water and refrigerant) of an entire system. Knowing this can help simplify even the most complex of situations.
Take a cookie-cutter approach to retro-commissioning. When you approach situations systemically, it’s harder to miss major components and becomes more natural the more you do these exercises.
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