Pump sizing

[Greenblood]

Does anyone know of a simple pump size calculator ? Ie that takes pipe size, length, number of elbows etc into account and recommend a pump spec? I have a Chinese heat pump with a failing condenser pump and I want to replace it with a easily sourced one. The problem is my pipe run is quite complex and I don’t want to under size it or over spec it.
cheers
steve

 

[MichaelK]

Isn't there a metal placard stamped onto the side of your pump with it's specifications printed on it? That's where I would start.

 

[solarsimon]

Start by establishing the flow rate, then use a calculator based on the length of the pipe run. Each fitting type has an 'equivalent length' so you just add the fittings onto the pipe length & recalculate.

 

[Greenblood]

The original pump had 36l/m flow rate and two speeds. It uses 22m copper pipe and has 9 elbows with a run of about 6m of pipe.
dose anyone know of a calculator to suggest a pump?

 

[solarsimon]

The original pump had 36l/m flow rate and two speeds. It uses 22m copper pipe and has 9 elbows with a run of about 6m of pipe.
dose anyone know of a calculator to suggest a pump?

Need height rise if not closed loop

 

[Greenblood]

Closed loop

 

[solarsimon]

Pressure Drop Online-Calculator​

Calculation output​

Flow medium:	Water 20 °C / liquid
Volume flow::	36 l/min
Weight density:	998.206 kg/m³
Dynamic Viscosity:	1001.61 10-6 kg/ms
Element of pipe:	circular
Dimensions of element:	Diameter of pipe D: 19 mm
	Length of pipe L: 9 m
Velocity of flow:	2.12 m/s
Reynolds number:	40071
Velocity of flow 2:	-
Reynolds number 2:	-
Flow:	turbulent
Absolute roughness:	.0014 mm
Pipe friction number:	0.02
Resistance coefficient:	10.51
Resist.coeff.branching pipe:	-
Press.drop branch.pipe:	-
Pressure drop:	234.97 mbar
	0.23 bar

Note: The pressure drop was calculated by the online calculator of www.pressure-drop.com. We can not warrant the correctness of this software. The software is produced carefully. But no computer software is without bugs. Therefore the calculations are your own risk.
***************************************************************************************************


6m of pipe plus 9 bends - where each bend is equivalent to 0.3m of pipe - hence 9m length.

So I expect most heating circulation pumps with that flow rate would do. Pressure loss is pretty trivial.

 

[Greenblood]

Ah great, so a decent metal bodied pump will do. Cheers