An MD80 captain returned to den after he was unable to pressurize aircraft.

Attributes
ACN	605694
Time
Date	200312
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : den.airport
State Reference	CO
Altitude	msl bound lower : 5431 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d01.tracon tower : den.tower
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude landing : roll
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	605694
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : diverted to alternate
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Unable to pressurize after takeoff in den, in either primary or standby mode. Chose to return to den than continue to dfw in manual mode. This caused an overweight landing in den. Landing was 'soft' and I returned to gate for maintenance and overweight landing inspection.

Original NASA ASRS Text

Title: AN MD80 CAPT RETURNED TO DEN AFTER HE WAS UNABLE TO PRESSURIZE ACFT.

Narrative: UNABLE TO PRESSURIZE AFTER TKOF IN DEN, IN EITHER PRIMARY OR STANDBY MODE. CHOSE TO RETURN TO DEN THAN CONTINUE TO DFW IN MANUAL MODE. THIS CAUSED AN OVERWT LNDG IN DEN. LNDG WAS 'SOFT' AND I RETURNED TO GATE FOR MAINT AND OVERWT LNDG INSPECTION.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.