Bypass and hydraulic separation: when does it help and when does it cause problems

A bypass can be used to maintain minimum flow, but if incorrectly adjusted, it can cause undesirable recirculation.

Positive use

It can protect the minimum flow rate when zones close.

Potential problem

If it opens excessively, hot water may return directly to the pump without passing through the terminals.

Result

Small ΔΤ, rapid cycling, and reduced actual efficiency in the space.