Low pressure water in peru

Hi

I have just built a 1 storey house in Peru. As it is a developing country water is a real issue. We have had mains water installed, but this is erratic at best. The peruvian solution is to have an external 1000 litre tank, ours is mounted at about 2.5m, which doesn't give enough head so a booster pump is needed. I know nothing about pumps so relied on advice from the local DIY superstore, Ace Maestro. They recommended a Petrollo pump with pressure tank.

When it is switched on the pressure is perfect so pretty happy. However the thing never shuts off. Am I right in thinking the tank regulates pressure to keep it constant. The guy at the store said that it would automatically switch on and off when water was required. Do I need an external valve which operates the switch or is something not set up correctly on the tank?

When you switch the pump off excess water feeds back into the tank. I was under the impression it should cycle off and on as pressure drops. We obviously don't want the pump running constantly or cycling constantly. Basically want higher pressure water when the mains is off when we turn the tap.My spanish is not great and the installation instructions only covered plumbing and electrical wiring.

How much air do you need in the tank?, how do you fill it and how often should it cycle?

Any help would mean I could have a shower in 35 degrees heat whenever I wanted!!

Cheers

I'm english by the way!!

You apparantly are missing two parts: a check valve to keep the water in the tank, and a pressure switch to turn the pump off once the desired pressure is met. The pressure switch is typically adjustable, and will have a high/low differential of around 20 pounds, or 1.4 bar. You need to have the air pressure in the dry (no water, and a valve open) set about 2 pounds less than the turn-on pressure for the pump. You can usually buy pressure switches preset to 20/40, 30/50. or 40/60 pounds, but they are probably all the same switch, and can be adjusted. So, the pump would pump up to the max pressure and turn off. As you use the stored water under pressure, when it drops to the lower value, the pump turns back on. You want the size of the tank to give you enough time inbetween cycles for the pump to cool off and not cycle all of the time. You may find, if you are say filling a tub that the pump can't bring the pressure up to the max and will run during the time you have to water running.

that sonds about right. How do you install the pressure switch? Does it go inline with the pump outlet then connect to the electrical wiring. The check valve is ok to get here and fit but have never dealt with a pressure switch.

Thanks for quick reply as weekends are the time when mains water is erratic!!

You install the switch close to the pressure tank on a "T" fitting. It isn't a bad idea to also install a pressure gauge there as well to monitor what's going on. The power goes through the pressure switch to the pump.

If this pump came without a pressure switch and check valve and you did not recognize it, then you will need some experienced help or a lot of reading to make it all good. I would get a pump guy to help - In Peru it can't be that expensive to hire it out?

Waaaay

Has a pressure switch and guage already fitted. The pump is a Bonnet italian pump with a 20/30 switch. Functions well. I eventually kicked the gasfitaro off the site and did some tests. The pressure switch works but it keeps cycling off and on. Forcing water back into the tank so will fit a check valve this afternoon. Also seems the guy had released all pressure of the tank as well. Need to get 2 bar in when the check is done.

Interesting story. Here Ace remove instructions from stuff like pumps so you have to pay for there service charge. Also had instructions for a Pedrello pump (?) given to us when we asked!!

Feeling pretty confident that it will all work later!1