With regards to sizing potable expansion tank, there are a couple of factors to be taken into consideration...for example what is The domestic water temperature rise Typically water is stored at 140°F So you will need your incoming water temperature And the difference is your temperature rise..... You will also need to know the domestic water pressure Your relief valve setting your relief valve setting Finally the size of your hot water tanks or hot water storage tanks! I do not know where you are located Here Ontario Canada we have what’s called TSSA which stands for technical standards and safety authority basically the police for a gas industry And pressure vessels when size your expansion tank use caution as pressure vessels when size your expansion tank use caution as any vessels, tanks over 22” in diameter require ASME Certification in other words If you perform a calculation and the result is a tank with a diameter over 22” it will greatly increase the tank cost!
You can avoid this by basically installing two smaller tanks, however depending on piping, fitting and labour cost, it may still be less expensive to just purchase the “ASME” and install one tank but I would check the pricing first! Also As mentioned I not know where you are located!
With regards to sizing potable expansion tank, there are a couple of factors to be taken into consideration...for example what is The domestic water temperature rise Typically water is stored at 140°F So you will need your incoming water temperature And the difference is your temperature rise..... You will also need to know the domestic water pressure Your relief valve setting your relief valve setting Finally the size of your hot water tanks or hot water storage tanks! I do not know where you are located Here Ontario Canada we have what’s called TSSA which stands for technical standards and safety authority basically the police for a gas industry And pressure vessels when size your expansion tank use caution as pressure vessels when size your expansion tank use caution as any vessels, tanks over 22” in diameter require ASME Certification in other words If you perform a calculation and the result is a tank with a diameter over 22” it will greatly increase the tank cost!
You can avoid this by basically installing two smaller tanks, however depending on piping, fitting and labour cost, it may still be less expensive to just purchase the “ASME” and install one tank but I would check the pricing first! Also As mentioned I not know where you are located!