Pump shut off delay when 2 nd pump operating

[Arttech92]

I have a question, anybody could help? We have two pumps 1 main / 1 spare, if we would to switch the 1 st pump to 2 nd pump in operating, and do not want to shut off the 1 st pump for few seconds, then how would be a reasonable delay we can consider to operate the two pumps before the 1 st pump shut of come for not having problem for the pumps and the system? (How many seconds?) If it delays long what would happen?

 

[Arttech92]

I should add it is centrifugal pump.. what about if it is PD pumps? What is a typical delay to be considered?

 

[Artisi]

Please don't double post, you should red-flag this one and leave the post in "pump engineering".

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[chicopee]

Arttch92, I hate to read badly worded posts.

 

[redlinej]

3 to 5 seconds would be engouh for the spare pump to bring up th pressure,but to have two pumps running at the same time it is good to have no-return valve on the output.Hope this helps