Required Clearances; Thermal Expansion - Bradford White RE2H50R10B-1NCWT Manuel D'utilisation Et D'installation

LOCATION (CONT).

Required clearances:

There must be a 7" (17.5 cm) clearance between any object
and the rear and sides of the water heater in the event service
is needed. A minimum 8" (20.3cm) clearance above the
water heater to remove the filter for cleaning and for service
access, and clear access to the front of the water heater, is
recommended. Installations that require 6" clearance on the
sides or rear of the water heater for earthquake straps are
also acceptable. In these cases, additional clearance must be
provided on the opposite side of the unit to allow for service
access. The hot and cold water plumbing and electrical
connections must not interfere with the removal of the filter.
If a separate ducting kit is purchased, additional space
is required above and to the rear of the water heater for
installation. Consult the ducting kit manual for specific
instructions.
AddITIONAL PARTS Needed:
1 - Flexible or Rigid Drain Line (3/4") and
associated fittings
14
Installation Instructions
3/4" MNPT
Condensate Drain Port
or
Catch Pan Installation (If required)
NOTe: Auxiliary catch pan MUST conform to local codes.
Catch Pan Kits are available from the store where the water
heater was purchased, a builder store or any water heater
distributor. The catch pan should be 2" (5.1 cm) minimum larger
than the Water Heater base diameter. To prevent corrosion
and improve Drain Valve access it is recommended that the
water heater be placed on spacers inside the catch pan.

THeRmAL eXPANSION

determine if a check valve exists in the inlet water
line. It may have been installed in the cold water line as
a separate backflow preventer, or it may be part of a
pressure-reducing valve, water meter or water softener.
A check valve located in the cold water inlet line can
cause what is referred to as a "closed water system."
A cold water inlet line with no check valve or backflow
prevention device is referred to as an "open" water
system.
As water is heated, it expands in volume and creates
an increase in the pressure within the water system.
This action is referred to as "thermal expansion." In an
"open" water system, expanding water which exceeds the
capacity of the water heater flows back into the city main
where the pressure is easily dissipated.
A "closed water system," however, prevents the
expanding water from flowing back into the main
supply line, and the result of "thermal expansion" can
create a rapid and dangerous pressure increase in the
water heater and system piping. This rapid pressure
increase can quickly reach the safety setting of the relief
valve, causing it to operate during each heating cycle.
Thermal expansion, and the resulting rapid and repeated
expansion and contraction of components in the water
heater and piping system, can cause premature failure of
the relief valve, and possibly the heater itself. Replacing
the relief valve will not correct the problem!
The suggested method of controlling thermal expansion
is to install an expansion tank in the cold water line
between the water heater and the check valve (refer
to the illustration on page 15). The expansion tank is
designed with an air cushion built in that compresses
as the system pressure increases, thereby relieving the
over-pressure condition and eliminating the repeated
operation of the relief valve. Other methods of controlling
thermal expansion are also available. Contact your
installing contractor, water supplier or plumbing inspector
for additional information regarding this subject.
Relief Valve Drain
Condensate Drain
Catch Pan
Catch Pan
Drain