Coates ST SERIES 5.5 & 11kW 240V SINGLE PHASE - Manual (Page 5)

PROBLEM INDICATORS POSSIBLE CAUSES ACTION
No Power to heater Check Circuit Breaker "ON".
Insufficient Flow Check that pump is running and filter is clean.
Flow Switch Inoperative Use Ohm meter to check continuity across switch while
pump is running. Replace Flow Switch if Open.
Flow Relay Inoperative Use Ohm meter to check continuity across NO and COM
terminals while pump is running. Replace Flow Switch if
Open.
Hi-Limit Reset Tripped Push "Reset" button
High Limit switch inoperative Use Ohm meter to check continuity across switch.
Replace High Limit Switch if always open.
Temp Control inoperative or set too low Adjust control higher or replace as required.
Check "HEATING" indicator light on temp display is "ON"
Contactor (upper) inoperative Replace upper contactor
Contactor (lower) inoperative Replace lower contactor
Flow light ON
Element light ON Heating Element(s) inoperative Replace Element(s) as required.
Heater too small for Spa Check heater sizing requirement of Spa.
One element inoperative on 11KW model Replace Element as required.
Temperature control inoperative, water
overheats in Spa. Replace Temperature Control.
Flow Switch not turning off heater when
pump/flow stops Check flow switch opens when pump is off. Replace as
required.
Heater subjected to high ambient
temperature (i.e. Direct sunlight) Cool Equipment room or shade heater from sun.
High Limit switch inoperative Replace High Limit Switch
Flow light ON
Element light ON Thermostat out of calibration/inoperative Replace thermostat.
Flow light ON
Element light OFF External heat source (i.e. Solar Heating,
heat from the pump, etc.) Turn off power to heater and verify problem continues.
No lights ON
Flow light ON
Element light OFF
No Heat
Insufficient Heat Flow light ON
Element light ON
High Limit
RESET Trips Flow light ON
Element light OFF
Water Temp
Greater than
setpoint
WARNING:
Only qualified personnel should attempt maintenance on this equipment. (NEC Article 100)
HEATER TROUBLE SHOOTING GUIDE
- CAUTION -
This heater incorporates 240 volt electrical circuits.
Do not open the case unless unit is disconnected from electrical power.
Use only manufacturer's parts, or UL listing and warranty may be void.
Elements can be checked with an Ohm meter only when power is disconnected from heater and all wires have
been removed from the element terminals. Each element should read approximately 10.5 Ohms.
Ambient temperatures above 120°F will cause the high temperature limit to trip prematurely.
Proper water balance is important to extending the life of your Coates
Heater. While pH control is critical, the control of alkalinity and calcium
hardness will protect against scaling and also help to prevent corrosion.
ACID ALKALINE
HEATER
CAN BE
DAMAGED
CORROSIVE
WATER
IDEAL
RANGE
ALKALINE
WATER
0 1 2 3 4 5 6 7 7.2-7.8 8 9 10 11 12 13 14
HEATER
CAN BE
DAMAGED
The correct level of sanitizer, pH, total alkalinity and calcium hardness will very, depending
on the type of pool (plaster, fiberglass or vinyl) and the chemical content of the fill water.
Water that is out of balance can damage your pool heater and void the warranty. This
heater is not for use in salt water pools.
PROTECTING YOUR COATES HEATER
WITH PROPER WATER CHEMISTRY