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Mudman

New Member

1

Tuesday, June 12th 2018, 7:38pm

Pressure Switch Question

Recently some mice ate through wires in one of my valve boxes causing a valve to not open. The pump didn't like this and eventually broke open a union downstream of the pump discharge. To avoid this in the future, I installed a pressure switch on the pump discharge to shut off the pump if the pressure exceeded the ordinary operating range of 35-45 psi. I set the pressure switch at 55 psi. However, when my orbit timer starts the pump there is a large (70 psi +) pressure spike which immediately shuts down the pump. What's interesting is that if I press the pressure switch reset button the pump works perfectly. Why the pressure spike when the timer turns on the pump but not when I reset the pump? Any help would be much appreciated.

Wet_Boots

Supreme Member

Posts: 5,236

Location: Metro NYC

2

Wednesday, June 13th 2018, 9:12am

Some controllers can energize a master valve or pump terminal a second or so a zone terminal energizes. You may need a small pressure tank alongside the pressure switch in order to ride out this pressure spike.

Mudman

New Member

3

Wednesday, June 13th 2018, 4:11pm

Pressure Switch Question

Thanks Wet_Boots, much appreciated. A small pressure tank upstream of the pressure switch should do it. I tried a different approach without success. I disconnected the pump wire from the controller and started the timer, assuming it would open the valves. After 5 minutes I reinserted the pump wire into the controller. No luck, the pressure still spiked. I then went to the pump, reset the pressure switch and everything worked fine. My thought was if that worked I could install a ON DELAY timer relay between the timer and the pump. Any thoughts on why that didn't work?

Wet_Boots

Supreme Member

Posts: 5,236

Location: Metro NYC

4

Friday, June 15th 2018, 9:39am

A delay unit might solve a pressure spike issue, but the pressure tank is your best bet, because of it providing a physical shock absorber to the plumbing. Also, the classical no-pump-relay-needed supply will have a pressure tank and a pressure switch, with a large enough tank giving you an always-pressurized water supply you might be able to use for things other than lawn watering.

RichMoney

Active Member

5

Wednesday, July 4th 2018, 9:27pm

You can also install a pop off valve on the pump or somewhere in the main line. Once the pressure reaches a specified point it will dump water out of the valvle.

https://sprinklerresource.com/

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