Seasonal effects - outside temperature - and operating boiler temperatures in typical two-pipe forced hot water systems are indicated in the table below:
It is common to design a hot-water heating system for a temperature drop of 20oC (36 oF) in heating elements and radiators at what is considered as minimum outside design temperatures.
Maximum boiler flow temperature is often set to 80oC (176oF) to avoid "burned dust" and accidentally injures on people when touching heaters. Outside design temperature depends on the actual location.
|Minimum Outside Design Temperature |
|Boiler Flow Temperature (oC) |
|Outside Temperature (oC)|
Heating systems - capacity and design of boilers, pipelines, heat exchangers, expansion systems and more.
Calculate gravity and forced circulating hot water heating systems.
Calculate flow rates in heating systems.
Required hot water expansion volume in open, closed and diaphragm tanks.
Hot water heating temperatures adapts to outdoor temperatures.
Free online design tool for designing hot water heating systems - metric units.
Online design tool for hot water heating systems.
Pressure loss nomogram for hot water steel pipes.