8
Expansion Tanks
Expansion tanks are required in addition to a Check Valve
for Closed Systems because pressure is created when water
is heated in the water heater.
The expansion tank has an air bladder which will contract to
relieve pressure in the system. The tank should always be
connected to the cold water piping between the water heater
shut off valve and the cold water inlet to the water heater.
Anti-Scald Valve
An anti-scald valve is required when the water heater ther-
mostat is set above 140°F (60°C). Also, an anti-scald valve
may be required for all installations by the “authority hav-
ing jurisdiction”. The valve is placed in the hot water supply
piping from the water heater downstream of the heating
loop connection and upstream of any domestic hot water
connection.
The purpose of the valve is to limit the maximum tempera-
ture available for domestic hot water by mixing hot water
from the water heater with cold water from the municipal
supply.
The Anti-Scald valve must be thermostatically controlled
and approved to the ASSE standard No. 1016 and 1017 for
use as an anti-scald device.
Plumbing
WATER HEATER
DOMESTIC HOT WATER
SUPPLY AIR
BLOWER
HEATING COIL
HRV/ERV CORE
CHECK
VALVE
RETURN AIR
COLD WATER INLET
ANTI-SCALD VALVE
(WHEN REQUIRED)
VALVE
(shut off)
VALVE
(shut off)
VALVE
(shut off)
VALVE
(balancing)
COOLING COIL
(OPTIONAL)
DRAIN
VALVE
EXPANSION TANK
(WHEN REQUIRED)
CHECK
VALVE
Closed Loop System
Time to Scald
(1st degree burns)
Temperature
Time
120°F
8 min.
130°F
20 sec.
140°F
3 sec.
160°F
<1 sec.
Conventional
Cooling
(Not available
through Airia)
Summary of Contents for CAF-D-L4A-36-P16
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