Stepdown from 2" to 1-1/2" to heater inlet?

[veedub]

Hi, first time spa owner and first time poster.

I purchased a new Raypak E3T 11kW heater and failed to realize that I have 2" tubing in my existing pump system. The Raypak E3T uses 1 1/2" plumbing connections. The next size up -- the 18 kW E3T uses 2" connections.

Should I sell the E3T on eBay and buy the one with 2" connections? Will I see a big drop in performance if I step the 2" pipe down to 1 1/2 for the heater inlet?

 

[PoolGate]

Yes, you will. If you can trade up, that is your best choice.

 

[JoyfulNoise]

I don't know if it such a big deal. If you look at the online manual, the difference in head loss for the 11kW unit versus the 18kW unit is, at most, 1.8ft at 60GPM. Obviously the heating almost doubles when you go to the 18kW unit BUT that's because it's running two heaters in parallel versus 2 heaters in series. For the 18kW unit, you need to use two 50AMP 2-pole breakers (so you use up four breaker slots) and the service panel has to have at least a 150A rating.

I'm not sure that the plumbing diameter is the deciding factor here especially if the reducer from 2" to 1-1/2" happens right at the heater ...

https://s3.amazonaws.com/AWSProd/sites/raypakcom/documents/241758.pdf

Perhaps @RDspaguy might have some advice here ...