Good day Members/ Comrades

I am wondering about something and I don't want to find out via the expensive way: Lets say you have a borehole pump coupled to a Hunter controller, controlled irrigation system. Now the Hunter controller has a 24Vac connection to switch the pump on and off via a relay. Now my question: I was taught to never run the pump without any open connection as it may burst the pipe (40 odd meters down)... Now with the Hunter controller, while switching from one zone to the next via the hunter solenoids, will it open the next zone before closing the previous zone or will there be a second or so when no zone is open - leading to a closed, over pressured system?

If that is the case, would it be possible to install a type of pressure relieve in the system to prevent "over-pressure" conditions from occurring by opening up to allow water out of the system?

Thank you in advance.

Kind regards,
Corné

Depends on the type of pump. A typical centrifugal borehole pump isn't damaged by  a closed valve. That only represents the limit of it's head.

If your pipes are half-decently rated I wouldn't worry about a short-time closed valve situation. The real  problem is that sustained lack of flow of water over the pump will cause the pump to overheat.

A positive displacement pump on the other hand will continue to build up pressure and burst your pipes before long.

@Corné,

I have more or less the setup of what you are looking for.

When my previous pump failed (the splines wore out, so motor is spinning, but pump stood still), i upgraded to a bigger pump - so i can open two circuits simultaneously - and installed one of the red pressure tanks, with a pressure measurement meters with built-in actuator. When pressure builds up to 5 bar, the pump switches off. When is drops to 2.5 bar-ish, the pump switches on. There is some heavy duty 3ph switchgear in the grey box against the wall that has a clear thud when it switches.

So now all i do is manually open and close the 24V valves, as i do not have a Hunter Control unit yet!

4 hours ago, Sidewinder said:

, as i do not have a Hunter Control unit yet!

How many Zones/Circuits do you have?

2 sets of 8 valves

On 2019/09/25 at 10:04 AM, Corné said:

Good day Members/ Comrades

I am wondering about something and I don't want to find out via the expensive way: Lets say you have a borehole pump coupled to a Hunter controller, controlled irrigation system. Now the Hunter controller has a 24Vac connection to switch the pump on and off via a relay. Now my question: I was taught to never run the pump without any open connection as it may burst the pipe (40 odd meters down)... Now with the Hunter controller, while switching from one zone to the next via the hunter solenoids, will it open the next zone before closing the previous zone or will there be a second or so when no zone is open - leading to a closed, over pressured system?

If that is the case, would it be possible to install a type of pressure relieve in the system to prevent "over-pressure" conditions from occurring by opening up to allow water out of the system?

Thank you in advance.

Kind regards,
Corné

Corne in my many years installing irrigation systems I have not seen a Hunter irrigation controller that has a time delay between the zones.

The only one I came across was a Nelson brand that they sold years ago. 

You might think there is a delay but its just the pipes being pressurized 

Thanks all for your replies. @Clint what you are saying makes a lot of sense. What I have perceived as being a delay may have only been the one zone pressurizing as the other one is depressurizing.