Return water pressure too low

our 1HP Hayward motor died last week. prior to this all systems were working fine. we replaced it with a 1 HP Century motor. Everything works except the water flow coming back into the pool is not strong enough to pop up the floor jets or push very strongly through the side return. there is enough suction to clean the top of the pool and run the vacuum. We have blown out all the lines, taken out the floor jets and cleaned them, taken out the jandy valve to make sure it is fully open, and tried it with the cartridge out. there are no air bubbles and the actuator valve is turning. Is it possible that the century motor is not as strong as the Hayward even though they are the same HP?
 
Welcome to the forum! From what I read you did not replace the pump, only dry end. We need ratings for old and new motors from labels and was the impeler changed? We have pump experts here that will help
 
If you still have the old motor take a picture of that label and the label of the new motor. There are other factors that affect output such as the service factor and whether or not a motor is up rated. The labels will help us interpret the differences between the two motors.
 
Oh poo, The pool center that sold us the new one took the old one. I do know that it was a Hayward super pump. you are correct we only replaced the dry end including the impeller. the new motor is a century 1 HP with a service factor of 1.1(I've been doing a lot of research). I think the Hayward motor has the same sf although I'm not positive.
 
That is the correct motor for the pump. But I am surprised that pump worked originally for in-floor jets because it is a pretty small pump and not very powerful. Have you tried cleaning the filter? What is the current filter pressure?
 
We have large cartridge filters. we took the filter out with no change in water pressure. there are no pressure gauges on the equipment that we have so I can only tell that the water flow back into the pool is weak by the sluggish movement of water and that the jets do not pop up.
 
We have large cartridge filters. we took the filter out with no change in water pressure. there are no pressure gauges on the equipment that we have so I can only tell that the water flow back into the pool is weak by the sluggish movement of water and that the jets do not pop up.

So everything was working with the old 1HP motor (pop ups, strong flow, etc)? Now, after you changed the motor (and impeller), you can't get things to work (even if you remove the cartridge filter)? It sounds to me like the new impeller you installed is smaller than your old impeller... maybe you accidentally got the 3/4HP impeller? That would explain it. Other than that, there's no reason why changing a motor (if the new motor has the same power) would have that big of an effect on your system.
 
Without a pressure gauge it is difficult to tell if it is a pressure side problem or a suction side problem. But given you just replaced the motor, I suspect something is wrong with the impeller. You may need to take it apart again to see if there is something obviously wrong with the impeller or diffuser.
 
OMG!!! Who knew a 1.00 gasket could cause such a problem. the pool center that we bought the motor from put it together for us---motor, impeller, diffuser. after we read your reply, we took the motor out and saw that there was no gasket on the diffuser! We put one on ,reattached the motor and everything works fine. I now know more about pools than this woman ever wanted to know. Thanyou,Thankyou,Thankyou!!!
 

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