Hydronic Flow Calculator
Proper flow management in a hydronic system is essential for ensuring safe and reliable operation. Use the calculator below to determine the necessary design flow and minimum flows for the selected boiler model based on specific site conditions.
Key Definitions:
- Design Flow at Operating Conditions: This is the required flow to maintain the selected temperature differential (delta-T) when the boiler is operating at full capacity.
- Minimum Flow: The minimum flow rate necessary to protect the heat exchanger from thermal shock, and to comply with warranty conditions. In some cases, this flow rate may be as low as 0 gallons per minute.
- Minimum Flow to Prevent Manual Reset High Limit (MRHL) Lockouts: This flow rate is crucial for preventing the supply water temperature from reaching the high limit setting of the aquastat, which could trigger a manual reset high limit lockout. Such lockouts can be inconvenient, requiring manual intervention to reset the system.
Input Parameters:
- Boiler Model: Select the boiler model for which you need to calculate the flow rates.
- Glycol Percentage: Specify the percentage of glycol in the hydronic solution.
- Supply and Return Temperatures: Input the system supply and return water temperatures.
- Safety Factor: The safety factor will be applied only to the MRHL lockout figures. The design flow and minimum flow are calculated without this factor.
Assumptions:
- Fuel is natural gas
- Cp values obtained from Dow DOWFROST PG