Hayward HCB110BTA, Troubleshooting Manual

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Replace HP switch.
Flow Chart HI/HP
HI(HP)
Does heat pump run for a
short time, then cut off
showing Hi or HP?
YES
Check Ohm’s reading on HP switch.
Reading 0 Ohms?
Heater runs for a while then shuts off and shows ‘HI or HP’ on
display. Low water flow is normally the problem. Check filter
and pump. A common problem when running unit on spa
exists when spa temperature of about 100⁰ F is reached and
the unit shuts off with the ‘HI or HP’ fault. At higher outdoor
and water temperatures a higher flow rate may be required
for proper operation. The unit requires a minimum of 30
GPM, but may require more under these conditions.
Note 1
NO
Check all wires and
connections
from HP switch to
control board. Wires
and connections OK?
YES
Replace control board
YES
Correct wiring
NO
See notes 1 and 2 below
HI/HP after the heat pump has run for a few seconds could
be an indication of a failed TXV. If the failure is caused
by the TXV, the low side (suction) pressure will fall rapidly once
the compressor is running, and the high side (head) pressure
will rise rapidly above 590 PSI.
Note 2