Fabdec EXCELSIOR, Installation Manual

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Secondary Return (where applicable)
Some Excelsior cylinders are fitted with a secondary return connection. Secondary circuit connections must be made to
the cylinder in accordance with the recommended installation diagram. A drain cock (not supplied) should be fitted in the
cold water inlet to facilitate draining of the cylinder (see Figure 1). A swept tee* is needed for all indirect models if
secondary circulation is required and is fitted as per the illustration. A non-return valve* must also be fitted to prevent
backflow. A pump* will be required to circulate the hot water. The return feed is in 15mm pipe and all work can be done on
site. *not supplied
IMPORTANT: IF A SECONDARY CIRCULATION CIRCUIT IS INSTALLED THEN A LARGER EXPANSION VESSEL
MAY BE REQUIRED TO HANDLE THE INCREASE IN WATER VOLUME. CALCULATE THE ADDITIONAL WATER
VOLUME AND CONTACT OUR CUSTOMER SERVICES DEPARTMENT REGARDING SUITABLE VESSEL SIZES.
Figure 1. Secondary Return
External Expansion Vessel (where applicable)
This smaller tank is connected to the cold-water inlet side of the vessel. Mount the tank according to separate
manufacturer’s instructions provided with the external expansion vessel.
A suitable expansion vessel with a pre-charge pressure of 3.5 bar is supplied with Excelsior cylinders with external
expansion.
The expansion vessel should be Tee’d off between the pressure relief valve and the cylinder (see figure 2) and should
always be positioned with the entry point at the bottom. Installation should always be by means of a standard T connector
ensuring no other valve is between this and the cylinder. Adjust the pressure to 3.0 - 3.5 bar.