My system has a whopping 150 gallons total and I am using an Extrol 90 as the expansion tank. Maximum temperature is 185 degrees, 12 psi factory precharge on the expansion tank and I am peaking out at 24 - 25 psi system pressure at the maximum boiler temperature I have set. I would like to lower the maximum pressure to around 15 psi as per the Thermo-Control manual.
I looked at Amtrol's website and see they have tanks that hold more water but most of them had the same acceptance volume as the Extrol 90. The SX-30V, 40V and 60V, along with the #90, all have acceptance volumes of 11.3 gallons. But total volume ranges from 14 to 32 gallons between the models. Why would you purchase anything other than the cheapest model if the acceptance volume is the same on all the models? I must be missing something big here - confused. Is the acceptance volume the amount it can expand or the amount it is filled cold?
I looked at Amtrol's website and see they have tanks that hold more water but most of them had the same acceptance volume as the Extrol 90. The SX-30V, 40V and 60V, along with the #90, all have acceptance volumes of 11.3 gallons. But total volume ranges from 14 to 32 gallons between the models. Why would you purchase anything other than the cheapest model if the acceptance volume is the same on all the models? I must be missing something big here - confused. Is the acceptance volume the amount it can expand or the amount it is filled cold?