B737 captain reported the elevator trim only worked in the pitch down direction.

Attributes
ACN	1502124
Time
Date	201712
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Flight Plan	IFR
Component
Aircraft Component	Elevator Trim System
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Total 10936 Flight Crew Type 656
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

Departed; at about 800 ft I noticed that I couldn't trim the aircraft nose up but nose down was working. I continued to hand fly and my first officer (first officer) ran the QRH. We called dispatch; tried on VHF with no luck and then HF. Got a patch with dispatch and [maintenance control]. [Maintenance control] said follow the QRH; as we did. I advised the lead flight attendant of our situation. [Advised ATC] as a precaution and requested to have the emergency equipment standing by. Landed runway xx; flaps 15 everything was normal; taxied to the gate.

Original NASA ASRS Text

Title: B737 Captain reported the elevator trim only worked in the pitch down direction.

Narrative: Departed; at about 800 ft I noticed that I couldn't trim the aircraft nose up but nose down was working. I continued to hand fly and my FO (First Officer) ran the QRH. We called dispatch; tried on VHF with no luck and then HF. Got a patch with dispatch and [Maintenance Control]. [Maintenance Control] said follow the QRH; as we did. I advised the lead flight attendant of our situation. [Advised ATC] as a precaution and requested to have the emergency equipment standing by. Landed runway XX; flaps 15 everything was normal; taxied to the gate.

Data retrieved from NASA's ASRS site 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.