Safe and Sanitary Hot Water Delivery Systems
https://www.caleffi.com/sites/defaul...nics_22_na.pdf
Caleffi has a series of these great free learning tutorials.
Planning my Domestic hot water recirculation system.
My 79 gallon Viessmann dual coil indirect water heater acts as a buffer tank between the boiler and the heated floor system. The bulk 79 gallons is used for Domestic hot water to fixtures, deep soaking tub etc.
This tank has an aquastat that is mounted in a well (thermal grease) that has a 30*F Delta-T
This aquastat controls the boiler fire cycles.
In winter I will set it to 140-170* & Summer I will set it to 120-150* TBD
At top of tank where DHW exits, I will not have the normal ASSE1017 thermostatic mixing valve (TMV)
Full tank temperature hot water will go through the insulated 3/4” red pex-a distribution/recirculation line.
This 3/4” pex line will run as close as possible to each fixture that requires hot water.
A short stub of 1/2” pex-a will tee off the 3/4” line.
At each fixture I will install an ASME1070 point of use TMV.
The Recirculation pump is a small Grundfos made for this purpose, it has a sensor & several modes of operation that I need to study.
The insulated recirculation return line will be 1/2” pex-a and enter the tank at the bottom through the drain port, this is to mix the bottom.