FAFCO 500 Series Installation Manual page 12

Overview (continued)
Retaining Ring
UV Resistant Bladder
Vent Cap
Internal Rubber
Air Bladder
Fluid Inlet or
Outlet
Mounting Holes
Function: Installed at the highest point of the system, it serves as expansion tank, air vent and pressure
relief valve. It allows for thermal expansion/contraction of the fluid without increasing pressure/vacuum
in the system. The air in the internal bladder inflates and deflates freely through the bladder vent cap.
When initially filled, the bladder fully deflates and air is purged through the air vent/pressure relief
valve. When not in operation, the cool fluid thermally contracts and the bladder inflates to accomodate
the reduction in fluid volume. During operation, the heated fluid thermally expands and the bladder de-
flates to allow for the increase in fluid volume. On the hottest day at maximum fluid thermal expansion,
the bladder will be fully deflated and any excess fluid will expel through the one-way air vent/pressure
relief valve. After this happens, all fluid expansion/contraction will be handled by the bladder.
Function: Cold water to ICM is connected to the storage tank using a tee with internal filter. During
normal operation, cold water is drawn into the ICM from the water heater's cold water inlet or cold water
supply during hot water use. Whenever hot water is used in the home, fresh cold water back flushes
filter putting any buildup back into the water heater. The self-cleaning feature prevents debris, sediment
or scale build-up from reducing system performance and potentially damaging the circulation pump.
Reducer and filter can be removed for cleaning if necessary.
11
SYSTEM OVERVIEW
COMPONENT OVERVIEW
(ON-DEMAND FOR GAS OR ELECTRIC)
Expansion Reservoir
Self-Cleaning Filter
Cold Water Supply
Nipple
20 Mesh
Filter Screen
Tee
Dielectric
Nipple
Water Heater's Cold Water Inlet
Reducer
Cold Water to ICM
UV Resistant
Air Vent/Pressure
Relief Valve, 1 psi
Black UV Resistant
Reservoir
Fluid Inlet or Outlet