Replacing single speed motor with a variable one

[makhmal]

Hello experts,
We moved to a new home and want to upgrade the pump for energy efficiency. We currently have a Century f56ac20z01 single speed (1.5HP attached), I want to replace it with variable speed either EVQ165 or EVQ225.
Edit: it’s a Pac Fab Challenger pump and we have Pentair Easy touch controller plus MX8 Elite cleaner.
Questions:
- Are the motors selected compatible with my pump?
- Is there any benefit to go for the higher power EVQ225 version?

Thanks

 

[dschlic1]

You will have to match frame. Look at the name plate of your existing motor and it should specify frame. Then find a variable speed motor with the same horsepower and frame. It should fit. Lacking that you could also go to a two speed motor.

 

[proavia]

The higher horse power motor will use less electricity to move the same amount of water as the lower HP pump.
Be sure to match the impeller to the motor HP.
Or buy a new pump/motor combination - that comes with a correctly sized impeller for the HP.

 

[makhmal]

You will have to match frame. Look at the name plate of your existing motor and it should specify frame. Then find a variable speed motor with the same horsepower and frame. It should fit. Lacking that you could also go to a two speed motor.

Thanks for your reply. The existing motor plate says 56Y frame. The variable speed options both mention 48Y. Googling the two gave me below answer:
What is the difference between 48Y & 56Y? Both have the same exact size square flange. The 56Y motor body diameter is 1/2″ larger than 48Y, so the 48Y usually includes a 1/2″ rubber spacer if required when mounting. Body diameter is the only difference, they can be inter-changed.

Should I be concerned?

 

[dschlic1]

No. I did that once with my pump.

 

[1poolman1]

Hello experts,
We moved to a new home and want to upgrade the pump for energy efficiency. We currently have a Century f56ac20z01 single speed (1.5HP attached), I want to replace it with variable speed either EVQ165 or EVQ225.
Edit: it’s a Pac Fab Challenger pump and we have Pentair Easy touch controller plus MX8 Elite cleaner.
Questions:
- Are the motors selected compatible with my pump?
- Is there any benefit to go for the higher power EVQ225 version?

Thanks View attachment 498913

Remember that while you can use the same relay that you use now to power your pump, an EVO motor has its own built-in timer (not clock). So far there does not appear to be a way to interface an EVO motor with anyone's automation.

When power is applied it will go into a set program that you pick of the many that are built in. You will need to read the directions carefully.

Look carefully at your existing motor for the service factor (SF). Multiply that by the nameplate's stated horsepower to get the true horsepower of that pump (impeller). If the number is 1.65 or less you can use that motor. If it is a true full-rated 1.5hp motor, it will have a service factor of 1.5 or a total horsepower of 2.25. You will need that motor. If not sure, go with the larger one.

 

[makhmal]

Remember that while you can use the same relay that you use now to power your pump, an EVO motor has its own built-in timer (not clock). So far thee does not appear to be a way to interface an EVO motor with anyone's automation.

When power is applied it will go into a set program that you pick of the many that are built in. You will need to read the directions carefully.

Look carefully at your existing motor for the service factor (SF). Multiply that by the nameplate's stated horsepower to get the true horsepower of that pump (impeller). If the number is 1.65 or less you can use that motor. If it is a true full-rated 1.5hp motor, it will have a service factor of 1.5 or a total horsepower of 2.25. You will need that motor. If not sure, go with the larger one.

Thanks for the detailed reply. The existing motor plate indicates SF: 1.1, therefore 1.65 should be the right choice so I don’t have to change anything else?

 

[1poolman1]

Thanks for the detailed reply. The existing motor plate indicates SF: 1.1, therefore 1.65 should be the right choice so I don’t have to change anything else?

Be sure to change the shaft seal and the sealplate O ring. If you get an original it is a "square" ring.

 

[makhmal]

Be sure to change the shaft seal and the sealplate O ring. If you get an original it is a "square" ring.

ECM motor received and installed, I seem to have serious air leak issue though. I’m not sure if it’s related to me doing some plumbing between the filter outlet and the heater (the new motor control box was too big for the room available), or something else. What I do know is that I could see air above the basket even before.
How can I address the air leak? As it stands, there’s no water flow (0 gauge pressure) when the motor is running at low speed.

Update, ran basic diagnosis, turned the valve to 100% skimmer and 0 cleaner, almost all air bubbles disappeared. Turning to 100% cleaner, lots of bubbles above the basket and through the return lines. So, I’m suspecting either the valve or something in the cleaner line. Tried soap foam around the valve, didn’t find any suction. It’s dark now, need to continue tomorrow!

 

[1poolman1]

Plumbing after the filter won't cause any kind of air leak. If there was an issue there it would be a water leak.
Very common for a gauge to read 0 with low speed water. It looks like we have the same filter and that's what mine does. Not sure how low you are setting the pump, or what program on an EVO is running, but with it running at the low speed open the air relief and if the pump is moving water it will eventually start coming out of the open valve. You get used to it.

 

[makhmal]

Plumbing after the filter won't cause any kind of air leak. If there was an issue there it would be a water leak.
Very common for a gauge to read 0 with low speed water. It looks like we have the same filter and that's what mine does. Not sure how low you are setting the pump, or what program on an EVO is running, but with it running at the low speed open the air relief and if the pump is moving water it will eventually start coming out of the open valve. You get used to it.

Low speed is 600, it’s not just 0 pressure, I put my hand in front of the return line and couldn’t feel any flow, besides I can clearly see that the strainer pot is not full of water when running at low RPM. This was with more than 50% going through the cleaner. I set it at 100% skimmer now, will check and report back shortly.

 

[makhmal]

Low speed is 600, it’s not just 0 pressure, I put my hand in front of the return line and couldn’t feel any flow, besides I can clearly see that the strainer pot is not full of water when running at low RPM. This was with more than 50% going through the cleaner. I set it at 100% skimmer now, will check and report back shortly.

Update: Low speed -600 rpm- 100% skimmer, pressure 2 psi and I can feel the gentle water flow on the return lines, Aka, air leak related to the clean line.
PS1: No (visible) air bubbles in the skimmer pot.
PS2: Minor water leak from the seal plate, need to check the seal and the motor level again tomorrow!
PS3: So far I’ve spent more time fixing the issues than enjoying the pool, hopefully this will change soon!

 

[1poolman1]

Update: Low speed -600 rpm- 100% skimmer, pressure 2 psi and I can feel the gentle water flow on the return lines, Aka, air leak related to the clean line.
PS1: No (visible) air bubbles in the skimmer pot.
PS2: Minor water leak from the seal plate, need to check the seal and the motor level again tomorrow!
PS3: So far I’ve spent more time fixing the issues than enjoying the pool, hopefully this will change soon!

A 1.65thp pump running at 600 RPM will have very little flow. That's why, on this forum, it is always recommended that, if you can, get the largest horsepower rated VSP and turn it down. To get the same flow, yours will just have to run a bit faster. You saved a considerable amount of money over purchasing a new pump, but will have to adjust to the changed circumstances.

Yes, be sure to stop a seal leak, if that is the case. On those Pac-Fab Challenger (as well as the Sta-Rite Max-E-XX) it is sometimes a leak at the O ring between the sealplate and tank-body. Before you take the pump apart again, take a small hammer and lightly tap near the bottom of the tank-clamp, on both sides, as you tighten the knob. You may find that the leak will stop.

 

[makhmal]

Update: Low speed -600 rpm- 100% skimmer, pressure 2 psi and I can feel the gentle water flow on the return lines, Aka, air leak related to the clean line.
PS1: No (visible) air bubbles in the skimmer pot.
PS2: Minor water leak from the seal plate, need to check the seal and the motor level again tomorrow!
PS3: So far I’ve spent more time fixing the issues than enjoying the pool, hopefully this will change soon!

Update: I managed to fix the water leak, it was the shaft seal (although I replaced it when changed the motor). The air leak is still there though, I’m more confident that it’s related to the cleaner line now. Flipping the valve to 100% skimmer, I don’t see any air bubbles in the pump skimmer pot and the filter pressure goes up 2-3 PSI, as soon as I transfer a portion of the flow through the cleaner, bubbles are visible, pump sounds different and air bubbles come out of the return lines too.
Not sure what to do next!

 

[1poolman1]

Update: I managed to fix the water leak, it was the shaft seal (although I replaced it when changed the motor). The air leak is still there though, I’m more confident that it’s related to the cleaner line now. Flipping the valve to 100% skimmer, I don’t see any air bubbles in the pump skimmer pot and the filter pressure goes up 2-3 PSI, as soon as I transfer a portion of the flow through the cleaner, bubbles are visible, pump sounds different and air bubbles come out of the return lines too.
Not sure what to do next!

If you have a Polaris 280, as in your signature, it has nothing to do with the suction side of the plumbing meaning no air leak from it.
If you have a suction cleaner, it could be in the hose connections. It could be in the O rings in the suction valve. It could be a pump-lid O ring that needs lube or replacing.

If there is even the slightest suction leak possible in the system, like O rings that are about to fail, pulling water from the bottom of a pool will increase the suction to the point that they will leak air. It could be at the drain plug on the hair-and-lint pot doing the same thing. Anywhere a pump can get air it will given the right conditions.

The inlet fitting has been threaded all the way into the front of the pump. That can damage even what appears to be a CPVC nipple. Put a bead of silicone sealant on that connection all the way around the fitting. That may stop the suction leak.

 

[proavia]

Speeds below 1000rpm tend to be inefficient.
While the electricity used is lower, the diminished flow rate offests the electric used.
Additionally, skimming action is basically nil.

 

[makhmal]

If you have a Polaris 280, as in your signature, it has nothing to do with the suction side of the plumbing meaning no air leak from it.
If you have a suction cleaner, it could be in the hose connections. It could be in the O rings in the suction valve. It could be a pump-lid O ring that needs lube or replacing.

If there is even the slightest suction leak possible in the system, like O rings that are about to fail, pulling water from the bottom of a pool will increase the suction to the point that they will leak air. It could be at the drain plug on the hair-and-lint pot doing the same thing. Anywhere a pump can get air it will given the right conditions.

The inlet fitting has been threaded all the way into the front of the pump. That can damage even what appears to be a CPVC nipple. Put a bead of silicone sealant on that connection all the way around the fitting. That may stop the suction leak.

Thanks again for the detailed reply. We had Polaris in the previous home, I managed to change everything about the new pool except the cleaner, we have MX8 Elite now.
I disconnected the cleaner hose from the wall to eliminate the hose leak option, still leak. I ran the quick spray test as they call it (stop the pump while watching the suction side), I saw water spray from the skimmer pot lid and the pump outlet to the filter.
I played with the outlet connection and cleaned put lube on the lid O-ring, re ran the test and this time only had lid water spray. So, ordering a new O-ring as I can’t see any cracks. Fingers crossed!

 

[1poolman1]

Thanks again for the detailed reply. We had Polaris in the previous home, I managed to change everything about the new pool except the cleaner, we have MX8 Elite now.
I disconnected the cleaner hose from the wall to eliminate the hose leak option, still leak. I ran the quick spray test as they call it (stop the pump while watching the suction side), I saw water spray from the skimmer pot lid and the pump outlet to the filter.
I played with the outlet connection and cleaned put lube on the lid O-ring, re ran the test and this time only had lid water spray. So, ordering a new O-ring as I can’t see any cracks. Fingers crossed!

Spray from the pump outlet will not cause a suction leak, it is under pressure, will only leak water, and should be repaired to stop the leak.
Lid water spray? What pump? The lid is under vacuum when the pump is running. Some pumps, most notably StaRite, will spray when the pump turns off even with a new O ring. Usually only happens with a single-speed pump that stops almost instantly when power is removed. VSP coast to a stop.

 

[makhmal]

Spray from the pump outlet will not cause a suction leak, it is under pressure, will only leak water, and should be repaired to stop the leak.
Lid water spray? What pump? The lid is under vacuum when the pump is running. Some pumps, most notably StaRite, will spray when the pump turns off even with a new O ring. Usually only happens with a single-speed pump that stops almost instantly when power is removed. VSP coast to a stop.

Well, I recorded the video, water spraying out from the lid gap when I suddenly stopped the pump from the control panel. Unfortunately I can’t (or don’t know how to) attach the video here. I have a Pac Fab Challenger pump.

 

[mknauss]

Unfortunately I can’t (or don’t know how to) attach the video here.

Put the video on youtube. Post the link here.