# Total Head for Raypak 6350ti Heat Pump

##### Well-known member
Hoping someone can help me out with this. I know most don't think it's important, but I'm trying to get a decent estimate on the total head for my pool plumbing. I'm looking into whether, or not, it is worth it for me to invest in a variable speed pump for savings on electricity. I've done a bunch of reading and research and have been able to calculate the feet of head for my pipes, valves, elbows, ect, ect. I was able to find the head for my Hayward cartridge filter, as well.
The only number that I can't seem to find (or make sense of) is for my Raypak 6350ti heat pump. There is a chart in the manual but the numbers don't make sense to me. The chart says that the pressure drop is 11psi @ 60gpm, which is fine... It then says to multiply that by 2.3067 to get the total head. That would mean the total head for just the heat pump is over 25!! That would be more than all my plumbing and fittings and filter, combined... which can't be right. I'm thinking that maybe that calculation is simply for the amount of 2" pipe...but that would mean the total head would be less than 2...which also doesn't seem right to me.
I'm hoping someone can simply tell me what the head is for this heat pump... or show me how to properly calculate it.

#### JamesW

TFP Expert
That’s accurate. You can go as low as 30 gpm, which will give you a 6 psi pressure drop or about 14 feet of head.

TFP Expert
Well like you said .... It's really not all that important of a thing to figure out. Plumbing head is a dynamic number and changes based on flow rate it's also not a liniar change.

So yes at 60gpm your heater could have a flow resistance of 11psi.

Here's the thing tho I can pretty much guarantee you will save money on you electrical bill with a VS pump. Much the same way the water flow is dynamic so is the power consumed by the pump. Simply reducing the motor speed by 500 rpm will cause the pump to use 50% less electricity. Dropping the rpm down to around 1200rpm will use roughly 1/10th the full speed power used by the motor. The trick is the past was to justify the price premium of a VS pump rather than simply switching to a 2-speed motor.

For you with both a SWG and now a heater being able to dial the pump in to meet the various flow rates of the different equipment will save you money in the long run.