It was 26 here last night in Alabama
I use coil blow out valves that go into the side of the head of the pump, with a small air tank or air compressor you can blow out all the water in your sysyem and hoses
Are these blow-out valves something you have added or are you talking about the stock blow-off valve that lets water out if the burner/water gets too hot
added, I will post pics tomorrow ..... someone pm me in the morning and remind me