Kohler Pump-What does everything do?

[Mishael]

Long story short, I bought a Kohler 73572-AA pump for a jacuzzi really cheap at a resale store. It was in very good condition but I know I can't get it to work right now because there is a circuit board on it that operates with a control box (which i do not have). The motor is powered through the integrated heating element (meaning if i just disconnect the heater, nothing will work) and there are a few wire leads coming out of the control box. I know there is a temperature sensor with two wire leads coming out, going into the circuit board, then coming out of that again and something happens when the temp of the water gets above 104°. Other than that, there are all sorts of wire colors going from the board, into the heater, then a few going into the coils. I would like to keep the heater functioning on a switch and be able to just throw a switch on the motor and call it a pump with a heat option. If i could, i would just remove the whole circuit board and wire the motor directly.
Is this at all possible?

 

[duffy]

Probably. The heater is almost certainly wired in parallel with the motor, which means you can separate the two and run them independantly. Trace the wires back - use a meter to find pairs that are connected across the low resistances of the heater and motor, there may be a similarity in the color codes of the loads to help. Read the specs on the motor housing, see if it's a 110V AC motor.

 

[Mishael]

I'm pretty sure the pump is in series post heater. the only wires that are going into the coils of the motor are a single blue one from the circuit board, one blue coming from the heating assembly, (which has almost a dozen wires connected to it) and two red wires which, when traced, lead from the coil, to a hefty capacitor, then back into the coils. The motor is also 115 VAC rated.

 

[duffy]

It sounds like you are saying you have two blue wires leading into a capacitor-start motor. The colors for this kind of motor wiring are usually blue and brown and a green or green yellow-stripe for earth ground. What's the resistance between the two blue wires?

 

[Mishael]

i have no blue wires going into any capacitors. There are 4 wires that go inside the coil. Two are blue, Two are red. One blue comes from the circuit board, the other from the heating assembly. The reds seem to form a loop. Following one from the coil, it leads to a capacitor where the other one comes out of and leads back into the coil. Other colors going to the heating assembly are green (which is indeed ground), yellow, orange (neutral line), white/black stripe, black, blue (on same screw terminal as electrical ground), and a grey, 2 element wire that is only to the temp sensor. the only wire listed above that does not connect to the heating assembly is the blue

 

[duffy]

Yes, two blue wires leading into a capacitor-start motor, like I said. I asked for a resistance reading between the blue wires.

 

[Mishael]

0.4Ω is what i got, which seems wrong

 

[duffy]

Yes, that seems too low. If you short the leads of the meter together, does it read "0" or "0.4"? Can you see a label on the side of the pump? See if there's a current and hp rating, see if it says "pump" or "pump with integral heater".

 

[Mishael]

it reads 0. it isnt my meter. i dont have the pump in front of me but as i remember, it is "pump with integral heater", although there are separate current ratings. the amps for the motor are 15.1 or .6 and its 2 HP. with the "6 amp" heater, it runs at like 18.something amps.

 

[duffy]

A 110V pump motor of that size and type, by itself, usually reads down around 2Ω or so, maybe a little lower. The impedance goes up when it spins, that's why it doesn't draw 55A and 6kw like you would expect from Ohm's Law.

You said you got this pump at a resale store, was it the one originally designed for the unit? You seemed to be saying there was an external heating element, is that right? Something a little smaller than a shoebox with a couple of pipe fittings? If so, did it come with the pump, or was it already on the jacuzzi?

 

[Mishael]

from what my research turned up, this pump is off of a kohler jacuzzi from the early 2000s and there is no external heating element. it is integrated into the pump. I dont actually have the jacuzzi, either. all i have is the motor, the water channel which encloses the impeller, and integrated into that right behind the impeller is a heating element.

 

[Mishael]

my meter was out of calibration. i was only reading the resistance of my leads which was .4Ω. So actually i have complete continuity between the two points that i checked.

 

[duffy]

Ok, so you've identified exactly where the heating element is, and the wiring to the element itself? Can you get a reading off it? I would expect to see 5 - 10Ω.

Have you run this assembly? If so, can you say what happens when the sensor goes above 104° - or does this require the part of the electronics you don't have?

If you can run it, put the sensor in boiling water and see if the pump shuts off or keeps running. If it keeps running, you're in luck - that means the heating element can be shut off without stopping the motor.

 

[duffy]

my meter was out of calibration. i was only reading the resistance of my leads which was .4Ω. So actually i have complete continuity between the two points that i checked.

So the reading across the blue wires is zero ohms, sounds like they are connected internally. That would explain the color, but it means we are missing a wire to the pump motor somewhere.

How much did you pay for this pump at the resale store? Have you ever seen it run? Pumps like this are usually quite expensive, like a thousand dollars. If it had a broken wire, that could explain a couple of things. In that case, you should open it up, and track down where the other wire should go.

 

[Mishael]

I'll post a picture in the morning of the wiring but it is very excessive and I do not believe it will run without first having the electronics that I do not possess. What is the wiring that seems to be missing? Also with the sensor, it goes into the circuit board but the strange thing is that it comes back out after passing through a few resistors so I think that the control box gets continuity through the sensor and shuts off the pump rather than the pump not operating through its own circuitry

 

[duffy]

What is the wiring that seems to be missing?

If the two blue wires are connected internally, then you are only showing one electrical connection to the pump motor.

 

[Mishael]

Yeah, that's what I'm saying

 

[duffy]

You need at least two connections to run a motor. If those blue wires are connected internally (and it sounds like they are) and the cap wires don't go anywhere else (which is what your description sounded like), then you are missing a connection somewhere.

A diagram would help. Have you had this thing running?

 

[Mishael]

I have never had it running. The cap wires only lead into the coils and then there are the two separate blue wires going in as well. I can get a picture up soon. From my experience with these, in theory it should work. There is also nowhere for another wire coming from the pcb to connect to anything. Basically it doesn't look like its issuing anything.

 

[duffy]

Look, this is really basic: you need at least 2 wires to run a motor, a lightbulb, a solenoid, a speaker - pretty much anything except an antenna. The 2 blue wires have 0Ω between them, they must be connected internally (which also explains why they are both blue) so that only counts as one wire.

Capacitor-start motors often have the second wire in common with one of the cap wires, but in this case you say they don't connect to anything else. That fits in with them both being red.

You say you have "experience with these", and "in theory it should work" - so where is the second connection from the motor?