OK, riddle me this, you’re standing in a pool store’s showroom and you’re in awe of all the shiny new pumps. You finally make your decision on the model you want and have a hunch it will work well in your 20 000-gallon pool, but the salesperson drops a bomb on your plans by asking the simple question, “What is your feet of head?” Wait a minute, what? My head is about 10 inches. but I’ve never actually measured my own skull…
Total Dynamic Head (TDH) refers to the total equivalent height that a fluid will be pumped by taking into consideration any friction losses in the pipe. Essentially “dynamic head” is the measurement of resistance working against your pool pump as it pulls water from your basin and pushes it back to the pool. The total sum of the pipes’ lengths, rise in elevation and addition of 45-degree /90-degree turns will affect the feet of head number. All the aforementioned plumbing quirks add up to more friction the water accrues as it travels. The more friction, the harder the pump must work to push the water through the pipe, which demands that you go to a higher HP or use a larger pipe.If you need to install a new pump or replace your filter, you need to calculate the system’s feet of head to determine the best fit. A pump’s flow rate is dependent on the feet of head.