Tarm install with thermal storage and backup oil is almost complete. I have only one large zone. Question: Shouldn't there be something to prevent return water that I'd like to go to the wood loop from going to the return of the oil system as well? It would seem that there can't be a check valve, as that would prevent the oil loop from functioning when that's called for. Will the water simply follow the path of least resistance, or will I be keeping my oil boiler hot with water from the Tarm?