Pomona, CA Clemmons, NC Nashville, TN
Tel: 908-355-7995 www.hayward-pool.com
USE ONLY HAYWARD GENUINE REPLACEMENT PARTS
41
Figure 222:
TROUBLESHOOTING
(continued)
Code Fault
Diagnosis Step
Remedy
LO
Water pressure
switch fault
1. Verify that the pump is
running.
This is a normal display when the pump is off. Turn pump on. LO
code should clear. If LO does not clear, proceed to step 2.
2. Verify that water
fl
ow is
adequate
Verify that water
fl
ow rate to heater is above minimum required (20
GPM). If OK, proceed to step 3
3. Check for faulty wiring or
connection.
Inspect water pressure switch wiring. Ensure wire harness terminals
are securely fastened to spade terminals on water pressure switch. If
OK, procced to step 4.
4.Verify state of water
pressure switch contacts.
Remove wire leads from water pressure switch and measure
continuity across water pressure pressure switch with the pump
running. If open, proceed to step 5. If closed, LO code is not caused
by water pressure switch fault. Reconnect wire leads to water
pressure switch.
5. Ensure that low pump
pressure does not exist.
Clean
fi
lter or clear blockages. Check position of valves in plumbing
system. If OK proceed to step 6.
6. Check for correct water
pressure switch setting.
Adjust water pressure switch setting as shown in Section III of
Installation Manual (only if heater is above or below water level). If
LO does not clear, proceed to step 7.
7. Water pressure switch is
defective
Replace water pressure switch.
Temperature
limit switch
fault
1. Check for faulty wiring or
connection.
Inspect temperature limit switch wiring. Ensure wire harness
teminals are securely fastened to spade terminals on temperature
limit switches. If OK, proceed to step 2.
2. Verify state of temperature
limits’ contacts
Remove wire leads from limit switch and jumper leads. Operate
heater. Measure continity across limit switches. If closed, LO code
is not caused by temperature limit switch fault. If open, proceed
to step 3. Remove jumper from leads and reconnect leads to
temperature limits.
3. Verify that water
fl
ow is
adequate
Verify that water
fl
ow rate to heater is above the minimum required
(20 GPM). If OK, proceed to step 4.
4. Temperature limit switch
is defective.
Replace temperature limit switch.
Exhaust gas
temperature
limit fault
1. Check for faulty wiring or
connection
Inspect temperature limit switch wiring. Ensure wire harness
terminals are securely fastened to spade terminals on temperature
limit switch located in the
fl
ue collector panel above the center of the
header. If OK, proceed to step 2.
2. Verify state of temperature
limit’s contacts
Remove wire leads from limit switch and measure continuity across
limit switch contacts. If closed, LO code is not caused by exhaust
gas temperature limit switch fault. If open, proceed to step 3.
3. Heat exchanger has been
damaged
Heat exchanger has been damaged. This is generally due to low
water
fl
ow, poor water chemistry, or a combination of these and other
factors. Rectify all issues with water
fl
ow through the heater and
water chemistry and then replace the heat exchanger and exhaust gas
temperature limit. Continuing to run the heater after this limit has
tripped will cause damage to the entire unit and will not be covered
by the warranty.