Description
When an AHU will not start or a chiller keeps tripping, every hour of downtime brings complaints. This guide gives HVAC technicians and maintenance engineers a clear, safe way to find the electrical fault – without guesswork and without replacing parts that were never faulty.
What you will learn
- How AHU and chiller power and control circuits are arranged, with a simple diagram
- A 6-step fault-finding method that works for any HVAC electrical fault
- The common interlocks – fire alarm, E-stop, door, freeze, flow, phase, pressure – and how to check each one
- Safety rules for working on HVAC panels and drives
16 symptom tables
AHU: no power, will not start on command, trips at start, overload trips, star-delta problems, contactor chattering, VFD trips, low airflow and BMS run-status mismatch.
Chiller (electrical side): will not start, compressor motor protection trips, high-pressure trips caused by fans or pumps, starter and soft starter faults, short cycling, crankcase heater problems and earth leakage trips.
Each table lists the likely causes in the order they are usually found, what to check, and what to do.
Also included
- Motor insulation resistance guide values (based on IEEE 43)
- Voltage and current unbalance checks with a worked example
- Overload relay setting for DOL and star-delta starters
- Monthly, quarterly and yearly preventive checks
- A printable fault record sheet
Format
13-page PDF, A4, readable on phone and printable. Download link sent instantly after payment.
Frequently asked questions
Who is this guide for?
HVAC technicians, service engineers, building maintenance teams and facility managers who look after AHUs and chillers.
Does it cover refrigerant faults?
It covers the electrical side. Where a fault is in the refrigeration circuit, the guide tells you to involve a refrigeration technician.
Is it specific to one chiller make?
No. The method and tables apply to most makes. Always follow your equipment maker’s manual for settings and fault codes.
Can I share it with my team?
Yes, within your own organisation. Please do not resell or publish it.
Need a panel? Wavetech Electricals Pvt. Ltd. designs and builds LT power and control panels in Mumbai for customers in India and abroad. Get an AHU or chiller starter panel quote.
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