If it still works, it will open before the pool is completely empty. But are you sure the valve is hydrostatic?
If it is not, then you will need to shop-vac the water remaining over the bottom drain, remove the drain cover, shop-vac the water under the cover, and then remove the lug nut and slide out the (manual) relief valve.
After a main water valve is closed the system's PVC pipes are still full of water and will drain to the lowest sprinkler head until the system is empty.
If you mean you are losing water, it may be a broken or cracked main drain or possibly your hyrdo-static valve is malfunctioning. One other possibility is a break in the pipe going to the main drain.
No. You cannot use the main drain to lower the water level below the skimmer. This is because the main drain is not really a drain. It only connects right back to the 3 port valve in the skimmer.
If its not connected through the skimmer I imagine it's there to empty it. hmmm, on the above. The main drain in pools is for circulating the lower part of the pool and is not intended to drain the pool as in a bath tub.
A lot of people confuse the hydrostatic valve at the bottom of the pool for a main drain. this is in fact not a drain but is there to allow water into the pool from outside if the pool is empty or partially empty to stop it from floating in ground water. Since hydrostatic valves are positioned in the sump next to the main drain pipe, unless you remove the drain grate you won't even see the hydrostatic valve. I have never heard of anyone mistaking one for the other as one looks kind of like a plug and the other is obviously a pipe. I have had to correct many of the answers from the original answerer of this and many other questions and would not follow any of his advice. I speak from 34 years of pool building and remodeling experience and am considered by my peers an expert in this field. I have drained about 20,000 pools and except for a handful of times have always used a submersible pump.
to empty the one on the main tuning slide, just hold the lever, or push the button, depending on the kind of spit valve you have, and blow air into the trumpet. To empty the one on the third valve slide press all three valves down, and push the lever/button on the spit valve, and blow air.
If you look at the pipe that is going into the filter pump you will notice that it has a tee that is peceeded by two or three pipes comming up from the ground. Those will be from the skimmer, main drain, and if you have one from the cleaner. If you observe the flow of water in the skimmer then change the valve so there is no more water flowing that will be the one going to the main drain or cleaner. Repeat the process to eliminate which one is the cleaner. Which ever one is left is the main drain.
You can get a back water valve. It is similar to a check vale/ the back water valve goes on your main sewer line out side of home. It is desined to stop black water form coming into your home if main line stops up. Thay do make a device that can be installed into an exsisting drain it lets water through your drain but will not let water back up through you shower drain.
Is this a sand filter? How many valves control the flow of water? It appears the b/w valve is defective.
No. to drain your radiator just undo the main bottom hose until it is empty then tighten it back up & refill the coolant system.
How do you know that the main drain is plugged? When was the last time that you back washed or cleaned the filter? If there is no flow at the main drain - check to see if a valve has been closed or adjust the variflow valve in the skimmer - located at the bottom of the skimmer- if you have that type of skimmer. Also check the pump basket - it may be full of debris.k
You can completely drain just do not leave empty for very many days or it may float like a boat.If you have a dew drain water will continue to come back into the pool from the main drain if the water table is high enough.