Pump Pressure Drop ( cont. )

[mike.m]

After receiving suggestions have revisited the pump with no joy as yet .

Tried the backwash for three minutes ; there was very little movement observable in the glass dome over the sand filter and the pump pressure dropped to zero .Is this normal?  If I release the pressure valve above the dome the water level rises . What is the correct height above the sand?

Air leaks ; Checked but none apparent .

Pump blades -work in progress . I removed the plastic fan at the rear and then unscrewed the four long screws which secure the body . I dont know how to proceed further . The main central nut turns freely when I insert the driver so I'm unclear how to dismount the main body . Also if its turning freely does that mean the impellor blades are not gunged up ?

Finally if  I have to replace it can I double check the correct power capacity for a 32 cu. meter pool .

 

                                                                  Thanks again

[Baz]

[quote user="mike.m"]

Tried the backwash for three minutes ; there was very little movement observable in the glass dome over the sand filter and the pump pressure dropped to zero .Is this normal?  If I release the pressure valve above the dome the water level rises . What is the correct height above the sand?

When backwashing the pump pressure may drop slightly but normal water movement in the sand filter should be seen. This certainly indicates a problem.

Pump blades -work in progress . I removed the plastic fan at the rear and then unscrewed the four long screws which secure the body . I dont know how to proceed further . The main central nut turns freely when I insert the driver so I'm unclear how to dismount the main body . Also if its turning freely does that mean the impellor blades are not gunged up ?

From your remarks it would appear the pump is working unless an internal gasket has blown.

Air leaks ; Checked but none apparent .

If all else fails before replacing a pump, it may be worth getting a pool company to carry out a pressure test on the whole system as this will find any air leaks.

Baz

                                                             

[/quote]

[steve]

the impellers could still turn freely, but could be full of gunge - it should be fairly straight fwd to remove motor and with it should come the impellers - where are you based ?

Cheers

Steve

[mike.m]

Hi Steve ,

              We're based near Dijon ; is there a way I can do a test for pressure leaks ( or confirm that the pump is pumping ?)

 

                                                                                   Thanks ,

                                                                                              Mike

[Théière]

Hi Mike how wet do you want to get?

If you undo the fitting from the pump to the sand filter, at the sand filter and run the pump you will soon see how much oomph is left in the pump it should pass a huge amount of water that even putting your hand over would be hard to stop, more than backwashing. That can also help clear debris to. (depending on the size of your pump also)

If the pump is ok, could be the multivalve gasket. When they go the water takes the path of least resistance so you can get a reduced pressure.

Can be the sand, if its old and stuck together chanels can form allowing water to pass too easily or even the vanes in the bottom of your sand filter. If they split water can pass quickly through the sand again forming a channel and reducing the system pressure.

Time to call in your local pool person if you don't want to do the job yourself.

[Weegie]

Perhaps the gauge is knacked?