Hayward Power-Flo Matrix Pool Pump: Electrical problem to diagnose

Lucien Nunes said:

The unit appears to be 12 years old and might have had significant runtime. Two likely causes of burnt crimp terminals exist: motor overload / winding failure or high resistance contact at the terminals themselves. Because the pump appeared to function normally and nothing tripped, and the heating seems to have been occurring for a while, it seems likely that bad contact at the connectors themselves is to blame. The motor's rated line current is around the maximum this style of connector can handle, so it doesn't take much degradation of the contact quality to raise the resistance to the point where overheating occurs. E.g if moisture has entered the housing and caused some oxidation of the plating, or that particular batch of connectors was not the tightest.

There is no reason to expect anything to trip as a result, as high-resistance connections will decrease, not increase, the line current. Evidently the insulation damage did not result in a fault to ground.

The discolouration caused by heating at the solder joints of resistor R1 is probably unrelated and normal. Power resistors like this are often marginally specced and run a little hotter than ideal, to save the maker a few cents. It is the dropper resistor that powers the electronics on the board.

If the existing unit is to be repaired, i would first energise the motor and measure its line current to rule out the possibility of an underlying fault. It would then be necessary to make excellent connections - better than the originals - to avoid a rapid recurrence of the problem. I.e. if the terminals were prone to overheating without any corrosion on the wires or contact blades, they will be more prone now. The PCB is rated for a 15A load but from experience these connectors are simply not reliable at that current.

Click to expand...

Lucien Nunes said:

The unit appears to be 12 years old and might have had significant runtime. Two likely causes of burnt crimp terminals exist: motor overload / winding failure or high resistance contact at the terminals themselves. Because the pump appeared to function normally and nothing tripped, and the heating seems to have been occurring for a while, it seems likely that bad contact at the connectors themselves is to blame. The motor's rated line current is around the maximum this style of connector can handle, so it doesn't take much degradation of the contact quality to raise the resistance to the point where overheating occurs. E.g if moisture has entered the housing and caused some oxidation of the plating, or that particular batch of connectors was not the tightest.

There is no reason to expect anything to trip as a result, as high-resistance connections will decrease, not increase, the line current. Evidently the insulation damage did not result in a fault to ground.

The discolouration caused by heating at the solder joints of resistor R1 is probably unrelated and normal. Power resistors like this are often marginally specced and run a little hotter than ideal, to save the maker a few cents. It is the dropper resistor that powers the electronics on the board.

If the existing unit is to be repaired, i would first energise the motor and measure its line current to rule out the possibility of an underlying fault. It would then be necessary to make excellent connections - better than the originals - to avoid a rapid recurrence of the problem. I.e. if the terminals were prone to overheating without any corrosion on the wires or contact blades, they will be more prone now. The PCB is rated for a 15A load but from experience these connectors are simply not reliable at that current.

Click to expand...

How could I improve these connections? By removing the connectors and soldering the wires directly to the board?

Click to expand...