Batch heater tank psi question

[isisbob]

I am replacing the tank on my 20 yr. old Cornell batch solar heater. Original tank is galvanized. I can get a galvanized tank to fit with a rating of 150psi. Is this sufficient or do I need greater psi? I used a std. hot water relief valve on it (150psi/210 degrees). Would I be better going for a stainless tank even though cost is much greater? Thanks for any help.  Bill

[Nando]

You are not supplying enough information.

Are you sure is galvanized instead of glassed ?.

Why do you need 150 PSI, so describe your system in detail.

What is the normal pressure in your system ?.

What is the size of the tank ?.

Stainless would be better but depends on your needs and water PH, I think.

What ever you use, make sure you get Electrolysis protection in the tank.

Nando

[isisbob]

Nando: Yes, its galvanized. It a pressure tank, not a hot water heater tank.

My system is a batch system with a 42 gal tank plumbed directly into the hot water line. The normal, unheated pressure of the system is approx. 50 psi.  The tank dimensions are 51" x 16".

My main concern is that as the water heats, the pressure increases. I don't know what the typical pressure of heated water is and I don't want to burst the tank.

What is Electrolysis protection? Are you talking about the fittings (i.e., galvanized to copper)?