I have a free-standing garage with a 1BR apt. on my property that has its own well. This building and well were on the property when we bought it. The well is 24 years old and was lightly used during that time. The previous owner lived there alone for 6 years, then we rented the place out for 2 more years. That's the extent of the occupancy. I've had it vacant for 12 years and want to get it in shape to rent it again. In 2016 the pump seized (probably from lack of use) and I had it replaced. The pump installer also installed a new brass nipple and 40/60 pressure switch. That pump has been very, very lightly used since its installation, with 30-40 gallons used every few months. This system has its original pressure tank, which is a steel, 44 gallon Flexcon Challenger.
According to the original well report, the 4" diameter bore well depth is 505', the casing depth is 75', the static level is 40', and the yield is only 2 GPM. When the pump was replaced in 2016, the contractor noted that the pump was on 480' of 1" black roll pipe. That pipe was reused with the new pump. The new pump (2016) is a 1hp, 5 GPM Myers. I don't know the model number, but it came with a general Pentair/Myers manual. The pressure tank is in the back corner of the garage and it is a schedule 40 PVC supply line that emerges from the garage floor slab and connects to the pressure tank tee. I'm guessing that pipe exits the building out the back of the building, under the slab, but I don't know this for certain. I'm also guessing that black roll pipe is buried from that exit over to the well, approximately 75 feet away, but I also do not know that for certain.
I have a CSV 1A on my main house well and want to use one on this well. I have 250 psi pipe on my main house but I do not know the rating on the pipe on this garage apartment well, but based on the age of the system and the modest cost of the building, I'm guessing that 160 psi pipe was used.
Here are my questions:
1. On my main house, I have back pressure of 150 PSI when the well pump kicks on and I have 250 psi pipe. Is the information I've provided enough to determine the back pressure that would be generated on the garage apartment system if I added a CSV 1A? I'm presuming I only have 160 psi pipe on that system.
2. I know this will be pretty impossible to answer, but is it most likely that when the schedule-40 PVC supply pipe that I see in the garage, running up from the floor to the pressure tank, exits the building, it then transitions immediately to black roll pipe between that transition point and the well? Is there a potential pipe-failure problem with using a CSV 1A in that situation?
3. Even though the pressure tank has had light use, will the diaphragm's days likely be numbered just because of its 24-year-old age, and would it be a good idea to replace it?
Thanks for any help and additional feedback.
