Inline Pump Questions

[urglik]

our new pump arrived.
i would like to operate it inline.
i'm thinking about priming issues.
if i use a lateral pipe and a descending pipe,
i'm thinking i can put a check valve on the descending pipe
and have a place to connect a hose on the lateral pipe
near the pump to flood with water.

would this work?

 

[MitchM]

I would not trust a check valve to hold water in the line for any length of time and that pump you pictured will become damaged if it's running without water.

 

[urglik]

I would not trust a check valve to hold water in the line for any length of time and that pump you pictured will become damaged if it's running without water.

my interest in the check valve is for the spring and fall when i would like to run the watercourse during the day, but turn it off at night if the temps are going to drop so as not to supercool the pond. so the length of time would be generally 12 hours or less i would like the check valve to hold water.

why aren't you confident of check valves in this situation?

 

[MitchM]

my interest in the check valve is for the spring and fall when i would like to run the watercourse during the day, but turn it off at night if the temps are going to drop so as not to supercool the pond. so the length of time would be generally 12 hours or less i would like the check valve to hold water.

why aren't you confident of check valves in this situation?

Check valves are ok for a brief power outage and to prevent a sudden rush of water back through the intake, but my experience is that over time they lose their seal because of debris getting caught in the flap mechanism.
You're not going to drop your pond temperature any significant degree by keeping the water running.
Your pond temperature will remain within tolerable levels as long as you keep the appropriate specie of fish.

 

[Meyer Jordan]

Biofilm grows on all submerged surfaces even check valves. When the water is flowing biofilm will colonize the valve seat. This will corrupt any seal the check valve may have when the water flow stops. The ensuing backflow may be small but it will occur. Over a period of hours this can become a problem in maintaining prime to a pump.

 

[Waterbug]

Other issues aside...that appears to a submersible, a name that seems to imply an option on being submerged or not. But they actually have, or should, be submerged to cool the motor. Inline (external) pumps are air cooled while submersibles are sealed, no air flow, no heat sinks. How long the pump would run outside of water is hard to say, hours, days, maybe weeks. But it would likely not be very long.

Getting an air tight seal on a hose for these types of things is very difficult. When submerged that isn't needed.

 

[Meyer Jordan]

Getting an air tight seal on a hose for these types of things is very difficult. When submerged that isn't needed.

This is very true.

There are mag-drive pumps that can be used either in-line or submersible. This appears to be one of them made by Danner.