Hello all - I've been dealing with issues with this system for many years. Mainly FP1 and E5 which I believe both are related to freeze protection when the EWTs get too low (i.e. below 15 deg f). During a recent checkup, the loop pressure was in the single digits around 7 PSI and do the tech pumped up. I know another tech increased the pressure from 27 to 38 PSI on a prior visit in January 2018. The average temperature is approximately 60-70 def f higher currently. Can this pressure loss be explained? Isn't this a closed system? I could see some variation dur to temperature differences, but this seems extreme and I'm wondering if this system might have a leak? Additionally, the EWT was in the mid-70s when the outside temperature is only in the upper 70s. These seems abnormal to me. I'd expect the EWTs to be closer to the 50s right now.