submersible pump question

I will try to keep this short. About 3 months ago I noticed that sometimes my well would cut on when the pressure dropped to the lower set point (45#). But pressure would just drop down to like 20# or lower and stay there with the pump running and it was unable to recover until you cycled power to the pump, turn off the breaker for about 10 seconds then turn it back on and pressure would build up fine. Well the pump finally died last night. The pump had 220v going to it but it was not drawing any current. So I pulled the pump today and installed a new submersible pump, however they installed a 1 ½ hp pump and the other one was a 1 hp pump. So the new pump was doing alright and I went to check my sprinkler system to see if I have to go up on the nozzle size due to the larger pump. And when I started the sprinkler the pressure dropped and the pump kicked on at 45# like it should then it dropped down to 25# or so and after 30 sec pressure built back up to normal then since I had the added gpm from the bigger pump, pressure built up to 60# and the pump cut off then of course the pressure dropped again and the pump started but this time the pressure did not want to build back up until I turned off the sprinkler valve. Side note the sprinkler is set up for 12 gpm and the old pump put out right at 12 gpm so it would stay running the whole time but the new pump is rated at 15-17 gpm. My few questions are:

1 why would the pressure not build back up. And would that have fried my last pump.
2 should I have something to limit the initial flow until all sprinkler lines are filled with water to keep the pressure from dropping that low (ie is it not good for the pump)
3 what size pressure tank do you recommend, the well is for the house and the sprinkler and right now I have a 20 gal bladder tank and it just seams like the pump cycles a lot while a faucet is running. (maybe 15 times a minute).

any help is appreciated
Jason

Check the current while this is happening. If the current stays high or normal, then the pump is moving water, and possibly you have two sprinklers open and the pressure cannot rise. If the current is low, then the pump is not moving water for some reason. When you figure out the reason for the delay in pressure, then you need a Cycle Stop Valve to keep your pump from cycling when using less than the max flow of the pump.

well i figured out my main problem the bladder pressure tank did not have any air in it the company who installed the pump originally never put any air in it. so now instead of cycling once every 3 or 4 seconds it is about once every minute. that is probably what killed the original pump. as far as the sprinklers go i will put new nozzles in so that it matches the output of the new pump so the pump comes on and stays on. do you recomend another bladder tank with that one to reduce the cycling even more. also should i install a backpressure regulator for the sprinkler or do you think it is ok. with the right amount of air in the tank the sprinklers came on the pressure droped slowly to 45# and the pump came on and the pressure slowly came back up to operating pressurenever fell below 45#. the air made a huge difrence in the way the well cycled, with the sprinkler and just with a faucet on.

thanks again for any help

A 20 gallon bladder tank only holds about 5 gallons of water. Your pump is putting out 15-17 GPM so, I bet it is cycling a lot. Normally I would use a MINIMUM of a 60 gallon tank, and an 80 gallon would be better. Then if your sprinkler system does not exactly match the output of the pump, you would really need two of the 80 gallon tanks just to keep cycling to a minimum.

Every time you double the size or number of tanks, you cut the cycling in half. Even with two big tanks, this can still be lots of cycling. However, a Cycle Stop Valve would make this into a variable flow pump, that would always match the pumps output to the amount of water you are using. A 20 gallon tank is all you need when used with a Cycle Stop Valve. And the CSV will eliminate the cycling, not just reduce it.

Your bladder tank should have come with air already in it. So the installer should not have needed to add any air. If it does not have air in it now, then your bladder probably already has a leak. This is understandable from the amount of cycling you would have with a tank that only holds 5 gallons and a pump that makes 17 GPM. The bladder will break from cycling just like bending a wire back and forth until it breaks.

Adding another tank would just be a band aid, where adding a CSV would be a cure for the problems you are having.