Written by Billy Ray and published on https://www.hunker.com/.
Winterizing a sand filter for your swimming pool is an important step in the closing and winterizing process for your pool, and certainly one where if you do it wrong you are very likely to cause damage to your equipment. If you were to fail to remove all of the water from your sand filter or filter head then you could definitely expect to see permanent damage in the spring (if you live in a climate that gets freezing temperatures in the winter).
Your filter is especially prone to damage from freezing water, and once a filter cracks there is no repair that can be made due to the dynamic movement of a pressure vessel and the danger associated with makeshift repairs. If you freeze your filter and crack it you will be shopping for a new pool filter in the spring.
How to Winterize a Sand Filter
A swimming pool must be properly winterized when not in use during the cold winter months. Proper maintenance of your pool’s equipment is essential to keep it running correctly. Drain your sand filter, water pump, and hoses and put them in storage when not in use. Most sand filters have a winterize setting that you can use when you are ready to shut it down for the year.
Clean out the filter by back washing and rinsing it out using the control lever and water pump. After the water is running clear from the nozzle, turn off the power and place it in the winterize setting on the filter top.
Disconnect the inlet hose from the water pump by removing the hose clamp and sliding off the end of the spout. Disconnect the filter’s outlet hose from the pool in the same manner. Connect one of these hoses from the skimmer outlet to the inlet nozzle on the pool.
Unscrew and remove the drain plug cap on the bottom of the filter barrel. Drain all the water from the filter and put the cap away in a place where it will be safe until the pool is ready to be used again.
Remove the pressure valve from the top of the sand filter to be sure it does not become damaged over the winter.
Disconnect and drain the water pump and all unused hoses. Place the sand filter, water pump, hoses, the drain cap and pressure valve in a dry, safe place until the pool is ready to be used again.
Original post here https://www.hunker.com/13418388/how-to-winterize-a-sand-filter.