Watlow EZ-ZONE Temperature Controller
Watlow EZ-ZONE Temperature Controller code AL.h1: AL.h1 (Alarm High 1, toggling with Attn)
The process value has reached or exceeded the high alarm setpoint, triggering an active attention message.
- Code
- AL.h1
- Name
- AL.h1 (Alarm High 1, toggling with Attn)
- Controller
- Watlow EZ-ZONE Temperature Controller
- Type
- Alarm
- What it does
- Warning: the equipment keeps running and flags a problem
- Risk
- GREEN In your wheelhouse
- Reset
- Clears on its own when the condition goes away
- Source
- The manufacturer's manual (subscribers see which manual and page)
Updated July 22, 2026
How to fix it
Subscribers get:
- What to do next, in plain words
- Which manufacturer manual it comes from, linked
- The 4 common causes listed for this code
- Booking a live video call with Ben, a master booth technician ($250/hr, paid per call)
Questions about this code
What does Watlow EZ-ZONE Temperature Controller code AL.h1 mean?
The process value has reached or exceeded the high alarm setpoint, triggering an active attention message.
Is Watlow EZ-ZONE Temperature Controller code AL.h1 dangerous?
It is graded green: in a working tech's wheelhouse with standard tools and low risk.
How do I fix Watlow EZ-ZONE Temperature Controller code AL.h1?
The manual's fix and the step by step check for this code are in WERCS Diagnose, plans from $49 a month. For help right now, WERCS answers 24/7 at (877) 489-3727.
Other Watlow EZ-ZONE Temperature Controller codes
---- · ---- (four dashes in upper display)OpEn · OpEn (Input Error i.Er value = Open)shrt · shrt (Input Error i.Er value = Shorted)AL.E1 · AL.E1 (Alarm Error 1)AL.L1 · AL.L1 (Alarm Low 1, toggling with Attn)Er.i1 · Er.i1 (Error Input 1, toggling with AttnvaL.L · vaL.L (value too low to display, less thvaL.h · vaL.h (value too high to display, greate
All 9 Watlow EZ-ZONE Temperature Controller codes · Every fault code