Feet Of Head Resistance

Feet Of Head Resistance, also known as Friction Loss is everything that the water must pass through within the circulation system such as plumbing and equipment. This is a very important factor in determining the flow (Gallon Per Minute) of your current pump, or if you are going to be replacing a pump. For pools that have already been installed, it is impossibe to determine the Feet Of Head Resistance; much of the plumbing is under ground. The following formula Is a general rule of thumb to determine the Total Feet Of Resistance.

First you must complete a couple of steps before calculating.

- Clean skimmer baskets
- Clean pump baskets
- You must have a properly functioning filter guage.
- Clean your pool filter. We mean really clean. For cartridge filters, clean cartridges as best as you can. For D.E. filters, you cannot just backwash, you must take the D.E. grids out of the filter and clean them as best as you can. For sand filters, if you know your sand is getting up there in age, now would be a good time to replace the sand, if it is still in good shape, a good backwashing will do.

- If your pool has multiple valves or you have a solar heating system, play around with your valves, turn solar off, then turn it on, this way you can get a high and low Feet Of Head Resistance rating.


Determining Feet Of Head Resistance

Step 1 Multiply Clean Filter Pressure By 2.31 = Answer 1
Step 2 Now We Need To Figure The Head Loss Factor Of The Pump, Use Table Below
Full Rated Motor HP Up Rated Motor HP = Pump Head Loss Factor
3/4 HP 1 HP 5.5
1 HP 1.5 HP 9
1.5 HP 2 HP 12.5
2 HP 2.5 HP 16
Step 3 Add (Answer 1) Plus Pump Head Loss Factor = Total Feet Of Head Resistance


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