High head loss with new heater

[crabboy]

Hello,

A catastrophic freeze event this winter cracked both my salt cell and heat pump caused by a Intermatic freeze switch failure. After the failure, I cut out both the heater and cell so the pool could continue to filter and I was in no rush to replace the components until the spring.

I've since replaced the Jandy AE-TI heat pump with a Jandy JXi 400k gas heater and the salt cell with another AquaPure, but now have the 3 port version. While adding the new components, I was able to remove 7 90degree bends in the pipe after the filter (yes, you read that correctly 7). After replacing all the components, I'm seeing much higher head loss and GPM though the pump.

Just so happens that I bought a check value flow gauge and put that in prior to adding the new gas heater. The reading before the new heater was about 95 GPM, but this was with the heat pump and old cell removed; however, the pressure at the return seemed about the same (based on feel) as with the two components.

Now with the new heater, the GPM has dropped to about 80 and the pressure at the filter has increased about 5psi. I first noticed the change since the pump was running quieter and the pump did not care if I closed off any of the inflow pipes. Before it would complain if it did not have at least two inflows wide open. The pressure at the returns is noticeably less.

I's not considering the new salt cell as an issue, since it has a larger cavity than the previous and allow more water to pass.

I contacted Zodiac/Jandy asking them for the head loss chart for my old Heat Pump and compared that to the new JXi chart. Yes there is more loss, but I'd think the more efficient plumbing after the heater would make up for that. The heat pump did have a built in by-pass (that's the **** part that cracked) and I think that is how it moved water so well. I'm thinking the efficiency no the new heater wants as much cool water through it as possible, so it has no bypass.

I plan to live with it, but I'd like to make some sense of it.

Thanks

Gary

 

[JasonLion]

It looks like the new heater adds roughly 12 ft of dynamic head, so not at all surprising it slowed the flow rate down a bit.

One minor pro in this, the lower flow rate means the pump is now drawing a little less electricity than it was before.

What specific model of pump do you have? I'd like to check if the pump is now closer to it's ideal operating range, or further away from it.

 

[PigIron]

I have the exact same heater installed. We also have an A&A infloor cleaning system. I had an A&A rep out to get the infloor cleaning system working correctly. He had to plumb in a heater bypass, as he said this new heater was very restrictive, which matches what you said. But as a result of the bypass, the fuse link inside the heater blew twice. We had to find a happy medium between the infloor cleaning, and the heater with respect to the bypass. We also had to increase the speed setting of the VS pump any time we wanted to use the heater to ensure there is enough flow through it.

 

[crabboy]

Thanks for the replies.

I have a 1 HP Jandy Stealth, SHPF1.0, wired for 220. That would be a plus if it was using less electricity. I would have assumed it would use more or just as much as before and just pump less.

It's good to know that it's not just me. I was thinking something fell in the pipe while I was changing the plumbing around.

Still waiting to fire up the gas heater... Plumbed in the water 2 weeks ago and the electricity this past weekend, now just waiting on the gas. Plumbers wanted my first born to install the 1 1/4" pipe 20' down the side of the house, once that's done (tomorrow) I need to wait for a new gas meter.

 

[JasonLion]

Looking at the pump curve, it looks like you are nicely in the efficient range both with the old setup and the new. If I read everything correctly, the GPM readings suggest only 8 ft of dynamic head were added, still not great but not as bad as what I estimated before.

Electrical usage is roughly proportional to water moved, so definitely a little less electricity used.