Will come in handy when I flush the system.

Be careful when tightening the fittings, especially the fittings in the Tankless heater, ensure you use a wrench to hold the fitting there not to twist off or damage the copper fitting piping inside the heater. And use the right size wrench and not pliers or channel locks, because you can damage or round off the the edges of fittings. Phasing the fittings is easy to get the alignment you need.

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