I have two IBN 1500 Lochinvar Intellifin boilers that keep going off on high limit. It appears that both boilers are running the same way regardless of what the sequencer is doing. We ultimately put the boilers on manual override and the same thing happens. We find that the ignition relay is applying 24 v constantly in the on cycle. The boilers do not modulate, it appears as if something is shorted. The factory says it is a flow problem but we have between 30 and 15 degrees delta T. Any ideas?