Good Evening!
Last winter our well pump died. We got a plumber out who replaced the pump at a fairly reasonable rate, but I think there was a problem. He "upgraded" our well pump from the prior 1/2HP version to a 3/4HP model. I didn't know much about such things at the time, but I now think this is problematic as the pump only seems to come on for a short period of time when water is being used, maybe 10 seconds. I understand this cycling could rapidly kill the pump.
We have a galvanized pressure tank. It doesn't have a bladder, and this is important because we have an iron reducing filter right after it which requires exposure of water to air in the tank to work. One plumber thought the galvanized tank is original to the house (1967). Given its age and the possible short cycling issue, I'm wondering if I should consider replacing it with a larger tank.
Anyone have any insights or advice?
Thank you in advance!
There could be two issues:
1) A the galvanized / conventional tank allows water to be in direct contact with the air in the tank. Over time the air will dissolve into the water and is removed when you use the water. This results in low pressure in the tank. This low pressure will cause short cycling. I believe the pressure in the tank should be ~2 PSI below the pressure the well pump turns on. If possible I would test the pressure tanks pressure and refill as the first step.
2) How quickly a well pump cycles depends on a few things; how big the tank is (the larger the less frequent), how high the water pressures is set (the higher the quicker as the air takes more space in the tank), and how much water is demanded ( pretty self apparent). If your tank is setup correctly and you are still short cycling a bigger tank may be needed, there are charts online you can reference.
(As a reference point, we have a low flow master shower, nebia 2.0, and only two people in the house and our well pump has cycled 42 times so far this MONTH).
As for the suggestion to replace the pump, I suppose it could be cost effective ... if you have a shallow well or a jet pump ... but a deeper well with a submerged pump, I don't know.
Edit: (well technically reviewing your post before I hit post): Are you worried about the well pump only running for 10 seconds at a time or are you worried that there are short periods between times when the well is running? My understanding of short cycling is that the well turns off and
on frequently when there is a water demand; basically the concern is the number of starts and stops. So, if your larger pump fills your tank quickly, but then rests for an extended period of time before restarting you are probably fine.
Here is some reading material if you want to dig a little further:
https://inspectapedia.com/water/Pump_Short_Cycle_Causes.php
