Crosswind V flow rate concerns

Jump to latest Follow Reply
N

nmqjstl

Member
May 21, 2022
5
St. Louis, MO
I recently installed a Crosswind V Heatpump, model 8550. I created a bypass so I can have water flowing around the heater. When I run my pump at 2500 rpm my filter pressure gauge reads 7 PSI (recirculate mode on multiport valve) and I see 60 gpm. I then turn my 3 way valve so water is routed fully through the heater and my pressure gauge jumps to 14 psi and my flow rate drops to 35 gpm.

It seems like any increase in pump speed above 20 gpm causes significant increase in pressure and drop in gpm.

Can anyone who has a crosswind v with a bypass share their filter pressure in bypass mode and in running through the heater mode?

I asked a friend who has a different brand heat pump and he said “needle barely moved, maybe 1 psi” so I am looking for a few additional data points.

And if anyone has seen something similar and has advice, I’d really appreciate it!!
 

Attachments

  • IMG_0663.jpeg
    IMG_0663.jpeg
    319.1 KB · Views: 3
  • IMG_0665.jpeg
    IMG_0665.jpeg
    398.2 KB · Views: 3
  • IMG_0664.jpeg
    IMG_0664.jpeg
    317.8 KB · Views: 3
  • IMG_0666.jpeg
    IMG_0666.jpeg
    334.9 KB · Views: 2
The high head loss is due to water moving through a small titanium tube that is also spiraled.

In my opinion, they need to double the diameter of the titanium tube to provide better hydraulic efficiency.

Water flows through the inner tube and refrigeration flows between the outer & inner tube (refrigeration loop).

The temperature of refrigeration and water are different, so heat will transfer from one with high temperature to the other one.

The flow is mostly counter-flow.

Bypass AssemblyDeluxe models include a bypass assembly. For standard models, the bypass assembly may bepurchased as a kit separately from Raypak. Part Number 100-10000816


Raypac Crosswind 8550 internal bypass?

We recently installed a new Rheem Raypac Crosswind 8550 electric heat pump. At the time of install the tech said we did not need to install an external bypass on the plumbing as there was an internal bypass already. My question how can we access that bypass and reduce the water flow? Since...
www.troublefreepool.com www.troublefreepool.com

1746718869675.png

1746718675296.png

1746718893275.png

1746718912739.png
1746719032904.png
1746719052612.png
 

Attachments

  • Crosswind_brochure.pdf
    3.9 MB · Views: 1
JamesW said:
The titanium tube is about 30 feet of small diameter spiraled tube, which presents horrible head loss.

In my opinion, the tubing needs to be a lot bigger and smooth.
Click to expand...
The trouble with larger/smooth tube is that it doesn’t transfer heat as well. I’d expect then to have more than one tube if the tubing is much smaller than 2” diameter so they can get more water through in the same time.
 
JamesW said:
A larger diameter tube has more surface area and that causes better heat transfer.

A larger tube with the same surface area but smooth will have the same heat transfer but better hydraulic efficiency.
Click to expand...
The spiraling creates turbulence in the fluid that ensures the water going through The tube gets mixed up as it’s traveling through much better than if it was a smooth tube, creating more heat transfer in shorter distance. We used almost the exact same set up in homebrew fermenting systems that need to cool down liquid wert very quickly. Non spiraled tube tend to allow the liquid near the center to pass through without contacting the Outer walls of the tubing.
 
For 40 GPM at 100,000 btu/hr, the temp rise from inlet to outlet is only 5 degrees.

Even if you want to use spiraled tube, going larger diameter will improve heat transfer and greatly improve hydraulic efficiency.
 
Thank you for all the replies. I am trying to discern how much this is specific to Crosswind V, or is this an issue with all heat pumps. I looked at BTU and COP when making comparisons, but admittedly did not factor in flow efficiency. I believe I would still have the option to make a swap if this is about this model, but obviously wouldn't bother if it is the same with all heat pumps.

Would I be better suited to switch it out for a Hayward or AquaCal? Anyone have opinions on better alternatives.

Edit: I just found this on the AquaCal website:
  • Patented hydraulic design adds only 2 PSI at 45 gpm, increasing compatibility with two-speed & variable speed pumps
Looks like I picked the wrong one.
 
Last edited:
  • Like
Reactions: JamesW

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Top Bottom
Back
Jump to latest Follow Reply