What is Head Loss?

an411

Active member
I am looking for a pump for my auto top off and what is exactly meant by max head loss?

Also if anyone has any recommendations on a pump to use I am going to have about max 10 feet from my RO/DI container downstairs to my sump.
 
head loss is a calculated value measured in feet that represents a theoretical maximum column of water that the pump can push up against. Imagine a pump with a piece of pipe pointing straight up. Now fill this pipe with water. Eventually, you'll add so much water that the pump can't move it any more. That's the maximum head loss.

If you're pumping DOWN to a sump, you probably don't need much pump, becausde gravity will do the work. However, be VERY careful about creating a siphon effect, where the water drains out of your RO/DI container into your sump, because there's nothing inherent in a pump's design to stop that, unless you use something like a peristaltic pump, like the LitreMeter from Spectrapure.
 
Yes, the smaller the pipe the greater the velocity thus friction loss. Fittings like elbows, tees, reducers and valves also play a part. Each one creates a restriction that adds head loss to the total.
 
I would think that for an auto top off that you are going to use a very small diameter tubing to pump water up to the sump. Someone correct me if I am wrong on this
 
I think the idea is the RO/DI is upstairs, maybe in the kitchen, and the sump is downstairs. I'd be more inclined just to have a gravity feed and a solenoid to regulate flow to the sump. This can be dangerous, take it from one who knows, if the solenoid fails. A double solenoid combo with both needing to open together is safer.
 
WK (and others) were interpreting your earlier posts to mean that the RO unit was UPstairs and the tank/sump were DOWNstairs. Is it that way or the opposite? Looks like what you just posted indicates the opposite.
 
My sump is upstairs and my Ro/DI water container is in my basement. I wanted to pump this water up to my sump
 
ahh! that makes much more sense.. if thats the case, you can just use the head-loss calculator provided earlier to determine what kind of pump you will need to go up 10ft based on your flow requirements and piping diameter.
 
It's gonna be a challenge though, since the calculator is aimed at return pumps, not something as low-flow as topoff.

Can you run a line straight off the RO unit upstairs to the sump? Rather than using a storage container. That way, the house's plumbing would provide pressure to get the RO water upstairs, you wouldn't have to pump it. You could use a solenoid and float switches or a float valve to control it.
 
I would go the solenoid with a backup route for simplicity. A peristaltic pump would also be a good choice since they can pump against gobs of head with no problem. Make sure you have a check valve at the bottom whichever way you go to prevent backsiphonage.
 
I could easily run the tubing fromt eh RO/DI unit to the sump but what would stop that from pumping? there is no electrical to stop it?
 
well, a float valve should do the trick, however many of our RO/DI vendors for aquaria purposes recommend against running the line directly to the sump.
 
I guess I am confused cause I turn a ball valve or something like a ball valve to get my water from my RO/DI now running this float switch how does this turn off the water flow? does it just not allow more water to go into the sump by closing the hole in the tube or something?

won't this cause for me to waste alot of water if this unit is always running?
 
Many RO/DI units have an auto-shutoff switch in the outlet hose of the RO chamber. If it gets too high it will shut off the inlet line..
 
Here's what you do.

1. you have your RO/DI unit creating fresh water. This water goes into a big container close by. You can fill this container once a week, if you like, manually. When you're not making new water, your RO/DI unit is turned off.

2. there is a pump in THAT container which has some tubing going to your sump. There is a float switch in the sump which turns this pump on and off, depending on water level in the sump.

The main point of this story is to NOT connect your RO/DI unit directly to your sump. Float switches can fail, solenoids, can fail, etc, and you don't want your RO/DI unit to run continuously and dump tons of makeup water into your sump.
 
MalHavoc you got it that is what I want to do. I do not want to connect the RO/DI unit directly to the sump cause I do not want to do exactly what you stated cause with my luck t hat is what would happen I would have a living room with a swimming pool. All I want to know is know that its possible to pump water 10 ft from my basement to my sump and have it stop with a float switch. The rest I guess I will figure out.


The only other thing that I was asking if this was possible is what kinda pump will work with this cause I obviously don't need a super strong pump that can pump 700gph or anything.
 
autotopoff.com or aquahub.com for the electronics..

If you really need to go 10ft vertical, you may have a problem finding a powerhead that will do that and doesnt cost you an arm and a leg.
 
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