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I have a well that is producing 30 gpm. This well is supplying water for the geothermal HVAC systems in my house (I am on public water for all other uses). When the HVAC systems are running, the water flow is approximately 18 gpm, and the pressure is approximately 40 psi. The relay on the storage tank is set to turn ON the pumop at 40psi, and to shut OFF at 60psi.

I had an irrigation company install an irrigation system this past week. The irrigation company used a combination of Rainbird 1812 PRS spray heads and 5012 rotors. As a side note, the designer had spec'd Toro 570 heads, but the people that installed the system used the Rainbird heads. I don't know whether this makes any difference.

On Friday, they powered up the system, and it is not working well. When the irrigation system is running, the water pressure drops to 35 psi, which is insufficient to raise the spray heads the full 12 inches (they raise perhaps 4 inches), and the water coming out is more of a pissing than a speay. The operation of the HVAC equipment does not appear to be affected; they continue to operate without any change in flow rate.

The well pump (a Grundos pump) is approximately 180 feet down the well, in the backyard. My property is on a slope. The storage tank, which is in the basement, is approximately 15 feet above the top of the well casing. The irrigation heads are approximately 10 to 18 feet above the storage tank (depending on the location of the particular irrigation head).

I have verified that when the HVAC systems are not running, the irrigation system works well. Thus, I have concluded that there is a pressure problem. The installers indicated that they will "go back to the lab" to figure out a solution, but I would like to see what people here think. I see three solutions. The first is to create an interface that shuts OFF the HVAC systems when the irrigation system is running. This solution is not optimal, because I have 11 zones, meaning the HVAC systems would have to shut down for several hours, which would raise the temperature in the house. The second solution would be to install some sort of pump to increase the pressure. However, this would likely be expensive, and I am not certain where the pump could be installed that would be away from the elements, close to an electrical supply line, and not create noise when it is operating. The third solution (that I see), would be to change the heads in the system to heads designed to operate under low pressure conditions. Are there such heads? Would the Toro heads (which the designer called for) have been better than the Rainbird heads? Would there be better heads still?

Finally, are there any other solutions that i may not have thought of yet?

Thanks
Steve

I checked with Grundfos today, the maker of the pump in the well. According to them, at 32 gpm, the pump will produce a pressure of 35 psi. As the flow rate decreases, the pressure increases. It is not possible to increase the pressure from the pump beyond the 35 psi at a flow rate of 32 gpm.

Unfortunately, the storage tank in the basement is approximately 10 to 18 feet lower than the heads. Thus, the water flow has to fight gravity. In addition, the supply lines to the heads have bends (the lines are not straight). This all serves to lower the pressure at the heads. As a result, I don't know what the actual pressure is at the heads. I wonder if this can be measured?

I looked over the original proposal, and note that the designer had spec'd Toro 4" inch pop-up heads (570 sprays), but that the installers used Rainbird 1812 and 5012 12 inch pop-up heads. Could this really make a difference? The installers said they were concerned that the 4 inch pop-up heads would not spray over the shrubs as they grew, and thus used 12 pop-up heads.

Steve

I do have a RPZ valve, along with an in-line filter. The valves are Irritol 2400TB. 1 inch pvc schedule 40 is used up to the various pipes. 1 inch Poly pipe is used from each valve to the heads. Flow rates, depending on the zone, vary from about 5 gpm to approx. 12 gpm (if I recall correctly).

The irrigation company is coming back to the house on Monday to look at the system. Over the telephone, the guy suggested it may be necessary to install a booster pump. I suggested trying different heads first and possibly changing the zoning.

He indicated that the first choice for locating a booster pump would be in the basement, after the pressure tank. Since my basement is actually a lower level, complete with bedroom, I am concerned about the noise of such a pump. Just how noisy are booster pumps? Anything else I should be aware of with booster pumps?

Thanks
Steve