Tuesday, December 18, 2012

Replacing the motor on a Hayward Northstar pump

Replacing the motor on a Hayward Northstar pump

This is a guide for replacing the motor on a Hayward Northstar pump by www.WCPandS.com. This is not a troubleshooting guide on determining problems with the pump. This will show the steps on how to remove and replace only.

The Hayward Northstar series pump can be difficult to work with. If you are unfamiliar with this specific pump and need to replace the motor, I would suggest calling a local pool service company to change it for you.

Click on any image to see a larger version.

What you would need to replace a Northstar pump motor

A replacement motor: The replacement motors for the Hayward Northstar are the round frame motors type. However, the thread size used for its impellers is not a standard size so you will need a round frame motor specifically made for the Northstar pumps. I used an AO Smith SN1102 1hp motor for this job.

The seal: The seal will be one of two different types used on the Northstar depending on your pump’s age. It could either be a SPX4000SA2 (for motors made 2003 and after) or a PS-3890 (for motors made before 2003). Pulling the motor apart and discovering (it would be obvious once the motor was opened) you had the wrong seal is always bad. They are about $20 each; if you are unsure of what you need, I would get both seals and return the one you didn’t use.

O-rings and gaskets: I used a go kit (Go-KIT66-9) that comes with all of the needed o-rings and gaskets (as well as a SPX4000SA2 compatible seal).

Tools Needed:
-Opened end socket (9/16)
-Socket wrench (9/16)
-Flat head screwdriver
-Phillips head screwdriver (may need to secure power wires)
-A swimming pool filter approved lubricant (use one screw before screwing them back in)
-Hex head screwdriver (to remove the motor plastic cover and ground wire)
-Needle nose pliers (to pull and bend the power wires)

May need:
-Pipe wrench (to unscrew the two large unions/nuts to free the Northstar pump)
-Automotive gasket maker

Ensure that the pump cannot turn on automatically or cause an electrical shock when working with the wiring. The easiest way is to turn off the breakers at the timer/automatic controller. If you are unsure of how to do this, then turn off the electrical breakers to the pool equipment at the house. If you are unsure of how to do this, do not proceed and hire a local professional.

If you need to clear the area around the pump to have access all around the pump, do it now before starting any work.
In this specific example, the pump could not be accessed without making room. The pipe going from the top of the pump to the filter inlet had to be removed. The filter also needed to be moved to free up space behind the pump to work on the wiring.

The pump was freed from the filter system by unscrewing the two unions (one in front and one at the top of the pump) that connect it to the filter system.

Disconnecting the power wires and conduit to pull the pump out

Note: Ensure that the power is off before starting these next steps. If you are not 100% certain the power is off, do not proceed any further.

To remove the wires supplying power, first remove the plastic cover from the rear of the pump.

This cover is held in place with two hex head screws. Once these are removed, the cover can be pulled straight back and off.

Inside are 3 wires (for a 220v pump): two are power lines (either matching color or not), and one is ground (usually green, always connected to a screw off to the side).

Disconnect the two power wires. In this case, they are connected with clips, but usually they are held down with one screw each.

Disconnect the ground wire by unscrewing the single screw holding it on.

Disconnecting the conduit elbow

Start by unscrewing the sleeve at the bottom of this connector.

Now pull the conduit back from the elbow to expose the wires.

The wires need to be pulled out of the elbow. Sometimes, it’s easier to pull one at a time and other times, it’s easier to pull them all out together. It may help to straighten the wire ends before trying to pull them out.

Remove the elbow from the old motor. In this case, the elbow had the nut on the outside. Normally, this is on the inside and needs to be unscrewed first before unscrewing the entire elbow.
You may have a bonding wire connected to the back of the pump. If you do, unscrew the hex head screw holding the bonding wire to the pump motor.

The pump should now be free and you can now pull the pump out of its current position. You will want to move the pump somewhere you have better access to all sides of the unit.

Separating the motor from the pump housing
There is a handle on the side of the pump connected to the large round ring that surrounds the pump (called the Motor Lock Ring).
You will notice that there is a clip holding the ring in place. This clip needs to be pulled up and off.

You can remove the screw holding the clip on if you are unable to unlatch it.

With the clip off, the handle can now be pulled up.

There is a line on the ring that will align with the top of the pump when the handle is all the way up.

Once up, pull the ring back towards the motor.

The motor can now be pulled back away from the pump body.

Note: This can be difficult to do, especially if you did not move the pump to a place where you can get better positioning around it. While separating these two, keep in mind how difficult they are to pull apart because it will be just as hard to push them back together near the end when installing the new motor.

A  flat head screwdriver can be used to help free the two from each other. When using the screwdriver, you want to free each side a little at a time until the two are separated.

Completely remove the motor from the front housing.

Removing the old motor
Pull off the motor ring (large ring/handle).

Pull off the volute (Diffuser) if it didn’t already fall off.

Pull off the impeller ring.

Pull off the large seal plate rubber o-ring.

The impeller now needs to be unscrewed. If you try it by hand, you will notice that it just spins on the shaft.

At the rear of the pump under the compactor is the back end of the impeller shaft. Use the open ended wrench to hold this shaft from spinning.

While holding the wrench, you can now unscrew the impeller. A large wrench can be used to grip the impeller to spin it off but be careful not to break it.

While impeller is separated from the housing, make a note of how each of the two seal parts sits in its respective section. When installing the new seal, its sections will need to be oriented the same way.

Pull the seal plate away from the old motor. It will now be loose since it was the impeller that held it in place.

Use the socket wrench (9/16 end) to remove the four bolts from the motor mounting plate. These could be difficult to remove if calcium has formed around the bolts.

The mounting plate can now be removed from the old motor.

Attaching the new Hayward Northstar motor to the mounting plate and impeller
Remove the new motor from its box.

Place the motor mounting plate over the new motor. Notice that the plate marks the up direction. The top of the motor is the side large white label (so you can read the motor information once the pump is installed).

Insert and tighten all four bolts into the plate, securing it to the new motor.

Note: In this case, a lubricant was used on each bolt so that the next time the motor is worked on, it will be easier to remove these bolts. This step is not required.

The two seal parts now need to be inserted into the impeller and the seal plate.

For the impeller, just pull the old seal off. If the bottom section splits in two parts, just pull the remaining section off.

Place the new seal over the impeller, noting which side is facing up (the visible side).

For the seal plate section, it is easiest to remove the old seal from behind with a flat head screwdriver.
Push the seal out.

Turn the plate back over and insert the 2nd part of the seal into the plate with the larger white side facing up. It is a tight fit so be sure to push the seal all the way down.

Reattach the seal plate to the motor mounting plate. Notice that the notch at the top of the seal plate aligns with the gap at the top of the motor mounting plate.

Note: A good time to check for debris stuck in the openings is before reattaching the impeller.

Screw on the impeller by hand.

To get it in tight, the back the new motor will need to be removed to expose the rear of the impeller shaft.

Using the 9/16 open ended wrench, hold the shaft still while tightening the impeller by hand.

Note: At this time, I also removed the plastic plug that the power conduit elbow will connect to.

Note: Since the bonding wire holder was removed when pulling the pump out, this new holder on the new motor will also need to be removed. When the pump is back in place, the old bonding wire clip will be used.

Place the impeller ring back on to the impeller with the lip side facing away from the motor.

The volute (diffuser) can now be reattached to the seal plate. It is pushed on, and then turned clockwise until it will not turn any further.

Connecting the motor to pump housing

Note: If you have it, replace the o-ring on the end of the volute (diffuser) now. If you don’t have a new o-ring, make sure the old o-ring is still attached at least.

Note: Make sure that the seal plate o-ring is on the seal plate. This is critical to help prevent leaks. Ideally, this should be replaced with a new o-ring anytime the pump is opened.

Pull the motor locking ring back over the new motor.

To attach the new motor to the front of the pump housing, the motor will need to be inserted at an angle because of the locking ring.

Notice how the motor mounting plate has a tab on top that matches a groove on the pump housing. Align these two and push the motor in to the pump housing.

The motor mounting plate needs sit all the way down so the surface is flat between the mounting plate and the housing. This can be difficult to do but I have found it is better to push the motor in to the housing quickly in one motion rather than to try and push slowly but with more force.

Once the two are reattached, the locking ring needs to be tightened between them. Notice the “open” and “closed” marks on the ring. These will line up with the top of the pump. Align the “open” mark, push the forward away from the motor towards the pump, and then pull the handle down until the “closed” mark aligns with the top. If you cannot turn your ring, the motor needs to be pushed further into the pump.

Reattach the clip to preventing the motor ring from moving.

Attach the elbow for the power lines to the back of the motor. Screw in the elbow by itself, then from the inside of the motor screw on the nut to the section of the elbow sticking through.

Note: If you moved your pump to work on it, place it back to its original position. When connecting the two unions, check that each still has an o-ring.

How to wire the new motor

Note: Ensure that the power is off before starting these next steps. If you are not 100% certain the power is off, do not proceed any further.

The loose wire ends need to be pulled through the elbow. The tips of the wires may need to be flattened out. It is generally easier to pull one wire at a time.

Once all the wires are pulled through, pull the conduit up to and into the elbow.

Tighten the nut over the conduit on the elbow.

Inside the motor, you will see “L1” and “L2.” Each power (hot) wire will attach to one of these.

In this specific case, the wires had clips on the end that attached to the ends of the “L1” and “L2” connectors.

Note: Normally, the wire ends are stripped, then bent into a hook shape and held down with the screws in “L1” and “L2.”

The grounding wire needs to be connected to the pump. The end of the wire needs to be stripped and turn into a hook shape small enough to fit under the green grounding wire hex head screw.

Attached the back cover to the pump and tighten the two hex head screws.

Reattach the bonding wire to the back of the pump.

Restarting the pump and checking for leaks

Open the pump lid and fill the pump basket area with water. Close the pump lid when the pump is full of water.
Turn the power of the pool equipment back on. Then, turn on the pump that the motor was just installed on.

If the pump does not power on, check all breaker switches. If it still does not power on, check the wiring on the pump as well wires in the timer/automatic controller. It is rare that a motor will be dead on arrival; however, it is possible especially if it was dropped during transit.

If the pump turns on but will not catch prime, check that pump lid is tight. If it still will not catch, then check that the lid o-ring is still in place.
If it still does not work, check that the front union is tight. It is possible that the o-ring in this union is missing or worn out and will need to be replaced.

If the pump leaks from its mid-section, either the motor and pump housing were not push far enough into each other or the seal plate o-ring is bad and needs to be replaced.