Suction System Guidelines
The suction system for the 2-speed pump or for the circ pump must be dedicated. There must not be any other pumps connected to this suction system.
The suction system for the 2-speed pump or for the circ pump must include the following:
A. 2 suction fittings, or
B. 1 suction fitting and a skimmer.
If the suction system for the 2-speed pump or for the circ pump includes a filter, it is desirable that the filter incorporate a by-pass around the filter cartridge that opens when the cartridge gets dirty. (Spring tension holding the by-pass valve closed must be overcome by the vacuum of the pump.) This by-pass should be capable of flowing a minimum of 20 gpm during the low speed operation of the 2-speed pump or during circ pump operation with the cartridge 100% blocked. The inclusion of a suction fitting appropriately plumbed into the suction circuit in conjunction with a vacuum filter may also meet this requirement.
Note: In some cases, a minimum of 25 GPM of water through the heater must be maintained. In some cases a specific flow direction is also required.