Is my Meg Stor Leaking

First the disclaimer.  Having worked in the HVAC business for a few years I am familiar with boilers and HW systems.  I also know I don't know everything so I'm here to see if what I think is wrong might be accurate.  I have a 7 zone systems with 5 radiant zones, 1 water to air zone, and 1 IWH zone.  The system works off an outdoor reset using the Taco reset control (I think it's made by Tekmar) and two Taco zoning panels.  Priority goes to the IWH. 



Here is the situation:



Over the weekend my relief valve on my Burnham Revolution gas boiler began popping off.  I checked the operating pressure and it was hovering around 30PSI, which explains why the valve was letting go.  I checked the automatic feed and I did have the valve closed (i normally keep it closed to make sure I know if there is a slow leak) on the boiler side of it so no water could be coming in that way, even if the valve was faulty.  Just to be sure I closed the (ball) valve on the other side of the feeder.  After relieving the pressure to around ~15PSI, I then checked the expansion tank.  It still had a charge and was not hot so it seemed to be doing it's job.  This may be my mistaken assumption.  After a short while, the pressure was back to 30PSI and the valve was spitting water again.



Assuming the expansion tank was not a problem, I started thinking about where fresh water could possibly be coming into the boiler if the feed was closed.  The only other thought was that the coil in the IWH was bad and was allowing the higher pressure potable water to enter the boiler system.  I shut off the valves to and from the potable side of the IWH and the pressure no longer was building in the boiler.  My conclusion, the Mega Stor 79 gallon tank coil is leaking, sending higher pressure water into the boiler system.



Does anyone here have any thoughts on this?  Any similar experiences?



Anyone in Harrisburg PA want to handle my warranty claim?