Pentair MASTERTEMP 125 - Page 43

MASTERTEMP 125 Pool and Spa Heater Installation and User’s Guide P/N 475114 Rev. F 8/2020
34 |
Heater Will Not Fire - B
Start
Service pump/filter and elimi-
nate other flow obstructions.
Heater should fire on call for
heat. Re-verify that water flow
is above minimum require-
ment.
Minimum Flow Requirements
Model Flow
200 20 gal/min (76 LPM)
175 20 gal/min (76 LPM)
250 25 gal/min (95 LPM)
300 30 gal/min (114 LPM)
400 40 gal/min (151 LPM)
If water pressure is outside of
adjustment range that will
open switch with pump off
and close switch with pump
on, replace with flow switch
set above minimum flow
requirement.
Model Flow
200 20 gal/min (76 LPM)
175 20 gal/min (76 LPM)
250 25 gal/min (95 LPM)
300 30 gal/min (114 LPM)
400 40 gal/min (151 LPM)
Is ERR PS displayed
on LCD?
NO
YES
YES
YES
NO
Verify that pump is on, filter is
not blocked, and the water
flow is above the minimum
requirement.
Check that water pressure is
within the adjustment range of
the Pressure Switch (0-5 psig)
Verify that switch wiring is OK
and Pressure Switch port is
not blocked, and replace
water Pressure Switch.
Check if any of the other
Alarms are activated.
Go to ALARMS Diagnostics
(Pages 36 and 37).
Go to “Diagnostic.
(Pages 36 and 37)
With pump running, adjust
Water Pressure Switch to
lower pressure until ERR PS
goes out. Then verify that
ERR PS goes on with pump
off.
YES
YES
YES
NO
NO
NO
CONTINUE
Minimum Flow Requirements
Section 3. Troubleshooting