Pressure up and down, surging heads

I just redid one zone in my system because of an addition to the house. 3 of my zones are working like they always have, good. the one I had to redo is action weird. Right now I only have two heads on that one zone. I turn on the system, the pump "pumps" up to what i call the max pressure and then cycles down, at the end the two heads are like spitting out water and then not, then spitting out then not, and so on, surging. What i did to the zone was remove about 3 heads (from 5 down to two) and instead of running 3/4" pvc all the around the house, i installed a adaptor (pvc to funny pipe) and ran the funny pipe to the two heads.

could that be my problem? going from 3/4 pcv down to 1/2 funny pipe and only having two heads?

thanks folks
Jake

That could be the problem. But it sounds more like a valve going bad. That's more typically the reason for surging like that.

I would recommend first just taking apart that valve. First, turn off water to the entire system. Then, once you get the top off and guts pulled out, turn water pressure back on to flush out the valve. Next turn water pressure back off. Next thoroughly rinse off all the parts you remove and replace them like they were originally. Tighten the valve back on and then try it. That may fix your problem.

If that doesn't fix it, replace the 3/4" pipe you removed.

Finally, if that doesn't work then you may need to replace the entire valve.

Thank you very much.

I didnt think it would be the valve because it comes on and shuts off with no problem and the pressure holds when it isnt running, no cycling of the pump that is.

oh well, dig the ditch back up and run the 3/4 all the way through.

thanks again
jake

If the original system matched up with the performance of the pump, then it is up to you to make the reworked zone match up as well. If you remove heads, then the remaining heads now are required to flow more water, which means changing nozzles. Or you might install the removed heads into the area remaining. Overkill, so far as the coverage goes, but you reduce the run time, and you're back in balance.

Well, I changed the piping a little bit. Instead of going from 3/4 down to the funny pipe, i went from 3/4 to 1/2 then to funny pipe, thinking the step-down in size would stop the pressure build. Nope. The easy fix.... I adjusted the pump. go firgure...

thanks for the input folks!

The problem is the pump is cycling on and off because you are not using enough water with that zone. If you have an above ground type pump, you may can adjust the pressure switch up enough to keep the pump from cycling. Of course this is the problem that a Cycle Stop Valve is designed to solve. The CSV will let you run small zones with a big pump without cycling. The CSV allows you to match the zones to the yard and not the pump. It keeps the pump from cycling and keeps you from wasting water, because you don't have to run extra sprinklers just to keep the pump happy.

Never heard of a CSV.... but that is something i ned to look into. I did a google search and came up with some really heavy duty ones. Are you familar with any online places that would have them for a simple 20/50 system? Easy to install?

thank you very much for this information, i do believe that this is my problem, I only have two heads on this one zone and before it was five. I did adjust the pump and all is good, but this sounds like a much better fix.

thanks again
Jake

*** just saw your signature with your web site **** what one would you recommend for a small system (1hp pump, 4 zones)?

CSV's are matched to the pump. What kind of pump do you have?

I am guessing this is the valve you need.

www.cyclestopvalves.com/prod_csv1_specs.html

Much thanks!