Art Monk  | 

We have a Caleffi separator just installed in a hydronic radiant heating system with two floor heating secondary circuits and one DHW heating circuit. We now find that when there is a call for DHW, the system also sends hot water backward into the two floor heating return paths (no pumps are on as thermostats are off on those circuits). It appears the hot flow from the boiler in the primary circuit is moving across and into the cold return on the distribution side of the separator. Is there any way to reduce or eliminate this type of flow ... or is it even perceived to be a problem? Prior to the installation of the separator we had closely-spaced T's to hook the secondary circuits to the primary. Thanks in advance for any wisdom you may have on this.