What is the purpose of a hartford loop?
A hartford loop was first designed to avoid all the water draining out of the boiler if a leak occurred in the wet return line. The old systems long before low water cut offs were invented, were piped at floor level and straight into the boiler. If a leak occurred the water would completely drain from the boiler and the coal fire would keep burning. The iron proceeded to get overheated, with no heat in the building. Someone would go to the basement to add water. The cold water hit the overheated iron and there was an explosion. The hartford loop will pipe from the boiler end of the wet return and go vertical to 2″ below the normal water level. If there is a wet return leak, the water would only drain as low as the hartford loop and keep a substantial amount of water in the boiler. See a drawing with a harford loop. View all the terms for near boiler piping.
