No pressure on gauge,pool is filtering but on off,cell tube fills up with water then emptys then fills up again

Clean the filter or replace it, it must be totally plugged.

check for a reset button on the heater side
check that the heater element is not failed

what is the water like?
Dirty? Green? Murky? Cloudy?
Something is clogging the filter!

Let me ask this, you said: "Pressure drops Off" ???
Do you have a pressure guage on the filter?
Does the pressure increase? Or does it Decrease?
This will be an important piece of information!!!!

• If pressure increases on the pressure gauge...
  • then filter is working and filtering out dirt and filter is clogging up.
• If pressure decreases on the filters pressure gauge,
  • then the basket, or literally anything that is decreasing or stopping the water from getting to the pump, or more precisely to the internal impeller of the pump!

Most commonly - plugged impeller, baskets need to be checked, enough water in pool? etc.

The same thing happened to me. So frustrating! I guess the pump that comes with the intex pool is not strong enough to do this. At least that is what I was told. So I just ended up sending that vaccum back and getting a catfish vaccum. Works great!

• Those spring type gauges break constantly, most likely broken again, they cost a couple bucks extra but liquid filled are much more durable, just don't forget to remove if you live where it freezes.

You may have a broken manifold. That's the part at the bottom of the tank where the filters set down on.With the filters out and the tank empty, fill the manifold with water. The water should stay put indefinitely. I the water level drops, you need to replace the manifold because even if the crack looks small. under working pressure in will open up and allow most of the water to bypass the filters altogether.

I'm assuming the pump runs, and the water is circulating from the skimmer back to the pool. Do have the pump running when checking pressure? Second be sure "filter" is selected on multi-port valve. Third, remove gauge with pump off and test gauge with compressed air and be sure gauge is working (don't overpressure gauge depending on gauge scale) If gauge is defective replace. If you still have no pressure on gauge, you might be "bypassing" the filter media (sand) due to a broken pipe from the bottome of the multi-port valve. You sould still see some pressure though as your pump should have some back pressure to the pool.

I happen to have a copy of the users manual for this pool filter. These are the instructions for operating your filter.

1. Be sure correct amount of filter sand media is in tank and
that all connections have been made and are secure.
2. Depress Vari-Flo control valve handle and rotate to
BACKWASH* position. (To prevent damage to control valve
seal, always depress handle before turning.)
3. Prime and start pump according to pump instructions (be
sure all suction and return lines are open), allowing the filter
tank to fill with water.
WARNING: ALL SUCTION AND
DISCHARGE VALVES MUST BE OPEN WHEN
STARTING THE SYSTEM. FAILURE TO DO
SO COULD CAUSE SEVERE PERSONAL
INJURY.
Once water flow is steady out the waste line, run the pump for
at least 2 minutes. The initial back-washing of the filter is
recommended to remove any impurities or fine sand particles
in the sand media.
4. Turn pump off and set valve to RINSE position. Start pump
and operate until water in sight glass is clear—about 1/2 to 1
minute. Turn pump off, set valve to FILTER position and
restart pump. Your filter is now operating in the normal filter
mode, filtering particles from the pool water.
5. Adjust pool suction and return valves to achieve desired
flow. Check system and filter for water leaks and tighten
connections, bolts, nuts, as required.
6. Note the initial pressure gauge reading when the filter is
clean. (It will vary from pool to pool depending upon the
pump and general piping system). As the filter removes dirt
and impurities from the pool water, the accumulation in the
filter will cause the pressure to rise and flow to diminish.
When the pressure gauge reading is 8-10 PSI (0.55-0.69
BAR) higher than the initial "clean" pressure you noted, it is
time to backwash (clean) the filter (see BACKWASH under
Filter Control Valve Functions.)

A better way to clean the filter tubes in the EC40 is to remove the filter tube assembly and soak it in a 5 gallon paint pail that is filled with a solution of water and a 20% muriatic acid, available at hardware and home center stores. Be very careful handling the muriatic acid. Don't splash it around.

Mix it in a 1-to-1 ratio with water and soak the assembly for at least 8 hours. Keep the soaking pail out of the reach of kids and animals.

Remove the assembly, properly dispose of the acid mix and refill the pail with clean water. Soak again for 3 to 4 hours, then reassemble your filter.

Some pool guys say it isn't necessary to soak the tubes in clean water because the muriatic acid will not harm the pool water and will reduce the pH if it's too high. I've always soaked them to be safe.

This is a link to the Hayward manual that describes the process:
www.haywardnet.com/products/Manuals/pdfs/manual9.pdf

Pressure gauge is stuck or defective. Tap on casing and see if needle fluctuates. prpbably just replace it for 11 bucks.