Harold Kestenholz
As this is a standard thermocouple heater, there is no intended purpose for this unit shutting off when the electricity shuts off – they are not intentionally connected. So a guess could say that they are unintentionally connected through the grounding system, which may be on the water pipes. A transient reverse AC cycle could break the low voltage of the thermocouple to drop out the gas valve. Perhaps a braided 12 gauge wire in an eyelet (screwed onto the thermocouple mounting bracket) to a grounded rod might bypass such transients, but there is no way to predict success.
