marcusj
New Member
I am installing a geothermal open loop system in my home. The system is 2 stage and will use ~5 gpm of well water on first stage and ~8 gpm on second stage. The system is sized so that it may run nearly continuously second stage in the dead of winter (i.e. 10,000 gallons/day). In the summer, it will never run second stage, but may run first stage for long spurts.
In any event, I know that my current well setup is not appropriate, and I am deciding what changes to make. I currently have a Myers 1 HP pump rated for 20 GPM. I compute my total dynamic head to be about 220 feet at 20 GPM. The well is pretty shallow at 50' with 18' static water level. We have an abundance of water, and the well can provide at least 30 gpm indefinitely. The well is less than 75' from the house and connected with 1" PVC. I am contemplating the following choices:
(1) Grundfos SQE constant pressure pump system (~$1400)
(2) Keeping current pump and replacing the pressure tank with a much larger tank (~$1000)
(3) Keeping current pump and existing tank size and adding a cycle stop valve (not sure of cost)
Note: my existing pressure tank recently failed and I've manually added air to keep it going so I will have to replace this even for option (3). Also, pump is 15 years old and may have experienced some short cycling before I discovered the pressure tank failure.
My question is what solution will work best for my current needs. Our existing system met our needs without the geothermal with the exception that the second floor water pressure was slightly low (system was set to 35/55). I think 20 gpm is reasonable for our needs.
As an aside, can anyone explain, how the Grundfos system works in the presence of two large water heaters. We will have two 85 gallon water heaters. One is a preheat tank for the geothermal desuperheater. Anyway, it does not seem like a little Amtrol ST-5 could overcome any heating expansion from the water heaters. Am I missing something or can their system work with a larger expansion tank too?
Sorry for the long post, but I appreciate any suggestions.
In any event, I know that my current well setup is not appropriate, and I am deciding what changes to make. I currently have a Myers 1 HP pump rated for 20 GPM. I compute my total dynamic head to be about 220 feet at 20 GPM. The well is pretty shallow at 50' with 18' static water level. We have an abundance of water, and the well can provide at least 30 gpm indefinitely. The well is less than 75' from the house and connected with 1" PVC. I am contemplating the following choices:
(1) Grundfos SQE constant pressure pump system (~$1400)
(2) Keeping current pump and replacing the pressure tank with a much larger tank (~$1000)
(3) Keeping current pump and existing tank size and adding a cycle stop valve (not sure of cost)
Note: my existing pressure tank recently failed and I've manually added air to keep it going so I will have to replace this even for option (3). Also, pump is 15 years old and may have experienced some short cycling before I discovered the pressure tank failure.
My question is what solution will work best for my current needs. Our existing system met our needs without the geothermal with the exception that the second floor water pressure was slightly low (system was set to 35/55). I think 20 gpm is reasonable for our needs.
As an aside, can anyone explain, how the Grundfos system works in the presence of two large water heaters. We will have two 85 gallon water heaters. One is a preheat tank for the geothermal desuperheater. Anyway, it does not seem like a little Amtrol ST-5 could overcome any heating expansion from the water heaters. Am I missing something or can their system work with a larger expansion tank too?
Sorry for the long post, but I appreciate any suggestions.