I moved my pool equipment - Now pump issues

[mat92495]

I renovated my pool deck and pool house. When we did this, we decided to take the pool pump and filter off the deck and place it behind the pool building. This added 40' of additional head. We have a 3/4 HP Hayward Super-pump from early 80's and a EC-65 filter. I did not give much thought to the added stressors until it was complete. Now we have a pump that will prime (after 30-60 second) but at full flow it drags the pump WAYYY DOWN and draws over 11 amps. FLA is only 7.4.
Pool piping is 1.5" everywhere
Floor drain and 1 skimer
2 jets
15000 gallon pool
added salt water generator
all underground piping is HDPE as was there from original, just added to with stainless steel barb joints and 3 stainless steel hose clamps at every fitting on each side. (1 of these for supply and return only)
All piping above ground is sch40 PVC 1.5"
pump will drag down so low that the starting circuit kicks in and out until i added a ball valve on the discharge and throttled it back to achieve proper pressure in the filter and allow the pump the come back to operating speed. I then modulate the discharge valve to find a good spot at 12PSI on the DE filter.
The pump will run at this spot indefinitely without overheating, but it moves a severely degraded amount of water to a point that vacuum cleaning would never be a possibility.
I am considering purchasing a new VSP 1.6THP from Hayward, but i do not want to be too soft on the HP, or be missing something else beyond my level of understanding.

 

[Texas Splash]

Welcome to TFP! I suspect @mas985 may have some hydraulic thoughts and recommendations for you. Stand by .......

 

[mas985]

I renovated my pool deck and pool house. When we did this, we decided to take the pool pump and filter off the deck and place it behind the pool building. This added 40' of additional head.

Just to confirm, you added 40' of pipe or 40' of head loss? These are not the same thing. Adding 40' of pipe will only increase head loss by a little bit.

We have a 3/4 HP Hayward Super-pump from early 80's and a EC-65 filter. I did not give much thought to the added stressors until it was complete. Now we have a pump that will prime (after 30-60 second) but at full flow it drags the pump WAYYY DOWN and draws over 11 amps.

Did the pump elevation change at all? What do you mean by drags the pump WAYY DOWN? If the RPM of the pump drops much below 3450, current will increase drastically and the thermal limiter in the pump motor will trip shutting of the pump. Is that what is happening?

But the change in plumbing should not reduce RPM at all. In fact, when head loss increases, flow rate decreases, current decreases so something else is going on. Does the pump motor make any noises such as loud squeals/screeching?

FLA is only 7.4.

Can you post a picture of the pump motor label?

Pool piping is 1.5" everywhere
Floor drain and 1 skimer
2 jets
15000 gallon pool
added salt water generator
all underground piping is HDPE as was there from original, just added to with stainless steel barb joints and 3 stainless steel hose clamps at every fitting on each side. (1 of these for supply and return only)
All piping above ground is sch40 PVC 1.5"
pump will drag down so low that the starting circuit kicks in and out until i added a ball valve on the discharge and throttled it back to achieve proper pressure in the filter and allow the pump the come back to operating speed. I then modulate the discharge valve to find a good spot at 12PSI on the DE filter.

This sounds like you have a suction side restriction. Post some pictures of the new setup.

Is there any air in the pump basket?

Can you post a video of the pump priming?