Lindy Coils & Hot Water Systems Part 1

By Luke Wonnell

If you own a Scotch Marine or cast iron sectional boiler in the NYC metro area, there’s an excellent chance you have one or more Lindy coils installed in the boiler, which provide all the domestic hot water for your entire building on an instantaneous basis.  Depending on the size of your boiler, there are Lindy coils available that can produce up to 10,000 gallons per hour of domestic hot water – that’s 167 gallons per minute – amazing!

Very simply, Lindy coils are bolt-on removable heat exchangers which allow the potable domestic water to pickup heat from the non-potable water/steam inside the boiler.  NYC boiler codes require the use of a mixing valve downstream of the Lindy coil, because the exiting water is well above scalding temperatures.  For Scotch Marine type boilers, the Lindy coil will typically be installed on the top of the front tubesheet (left photo below) while for cast iron sectional boilers, the Lindy coils are installed in one or more of the intermediate sections (right photo below).

There are many different configurations of Lindy coils available – the image below shows just a few of the available configurations:

Source: http://www.dhtnet.com/products/dht-lindy-tankless-coils/