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AHU-FC13 · Air-side AHU · ASHRAE Guideline 36 FC13

Supply air too warm with the cooling valve full open

The cooling coil is doing everything it can and the supply air is still above setpoint.

Capacity-basedBAS trendsGuideline 36Medium effort

What does AHU-FC13 mean?

The cooling coil is doing everything it can and the supply air is still above setpoint.

Why does it matter?

Zones downstream will drift warm and the chilled-water plant is being asked for capacity it can't deliver here — low CHW flow, warm CHW, a fouled coil, or an undersized coil.

What should you do?

Check chilled-water supply temperature and differential pressure at this AHU; look for a closed isolation valve or air-bound coil; clean the coil; compare against the plant's CHW supply setpoint.

How Energy Agent prices a finding

Written by Pelorus Engineering · Brent Waluzak, P.E. (FL), President, Pelorus EngineeringLast updated
Estimate it

What should the economizer be saving?

Estimate the free cooling a working economizer delivers in your climate.

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Share of those hours the economizer actually displaces mechanical cooling.
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    Cooling capacity, times the hours a year outdoor air can do the job in your climate zone, times an effectiveness factor, priced at your rate. Energy Agent counts the actual hours the coil ran when it did not need to.

    Screening estimate. Energy Agent measures the real fault hours and load from your trends and prices them at your tariff.

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    Screening-level estimates; confirm with measurement and verification before capital commitment.

    More air-side ahu faults

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    Send twelve months of interval data and a BAS trend export. Energy Agent returns a ranked list of what is wasting money, what each item is worth per year at your tariff, and what to do about it.

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