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Clanging Boiler on start up
My boiler makes two loud of clangs within 20 seconds of firing from cold. It's a Burham V904A with a Beckett gas burner. I don't think it could be a water hammer in the pipes because all of the pipes are cold and there is no air moving through them since the boiler water is cold.
Is this likely just the thermal expansion of the boiler or should I be concerned?