I just started having an issue, the pellet boiler is running and getting up to temp according to the guage on top, but the oil boiler its connected with temp is not going up. It used to match or close to it with the pellet boiler temp. And theres very little to no heat coming from my baseboard. If i turn pellet boiler off and just use my oil boiler it works fine. SO whats causing this to not heat with using the PB?