by Gary Mann
The Reverse Return arrangement is useful in Services Layouts. It is used for connecting modular components such as Radiators, Cooling Coils etc. to ensure that there is approximately equal flow/resistance through each component as opposed to a Parallel, or Direct Return system which tends to favour the first emitter and potentially short circuits the flow to the hydronic units further downstream.
To demonstrate I will populate a single room with 4 radiators using “Autoplace Radiators”.
Clicking on “Place” puts a radiator under each window and indicates the success and room failure rate.
Next, connect a Flow pipe to the radiator furthest away from the Entry Point, see below.
Then, connect a return pipe to the radiator furthest from the Return Exit Point, as below. N.B. Do not use “Edit>Clone Returns” feature, as this follows the route of the Flow pipes creating a Parallel Flow & Return system, which is not what this article is about.
Then use “Autoconnect Emitters”. Leave the Maximum Connection Distance as 1.0 m as this will be sufficient in this case.
This completes a simple reverse return system. To summarise, Radiator 1 has a short Flow, but a long Return and Radiator 4 has a long Flow but a short Return. So all Radiators have a similar length of connecting pipes and hence easier to balance.
Closing Question - Which Radiator would form the Index Circuit or would they all have equal circuit resistances?
Answers on a postcard to gary.mann@cadline.co.uk