43
Page
•
Priority Control Devices
such as a flow switch, an Aquastat or other electronic
controller can be used to prioritize the domestic water system over the heating
system.
•
Follow all local codes, or in the absence of local codes, follow the current edition
of the National Standard Code, ANSI Z21.10.3 • CSA 4.3.
•
This illustration is a concept design only. The reference to the 1/8
th
hole in check
is only for the State of Massachusetts. There are a wide variety of variations to
the application of controls and equipment presented. Designers must add all
necessary safety and auxiliary equipment to conform to code requirements and
design practice. For more details, contact the manufacturer.
•
The built-in pump may not provide sufficient flow for the heating coil. An
additional field-supplied pump may be necessary.
NOTICE
-Dual-purpose hot water heating-
(Domestic and Space Heating):
Diagrammatic layout of radiant heating and domestic water heater.
The recirculation pump is to provide no less than 2 GPM (7.5 L/min) and no more than 4 GPM (15 L/min)
through each activated unit in the system
120 VAC
switch or
outlet
Hot w
at
er outle
t
Unions
T-handle gas shutoff valve
Check valve
Electronically controlled
pump timer. Activates
every 6 hours for 60
seconds. Wire to
product approved pump
Heating Coil
(used with air-handler)
Cold water supply
3-inch gas exhaust
vent (Discharge must
comply with local and
state codes.) Cannot
be common vented
with other appliances
in Massachusetts.
An approved temperature and pressure
relief valve. Tie to location approved by
local codes and must meet BTU rating of
water heater model used
Check valve will have
1/8-inch hole drilling
in clapper optional
Atmospheric
vacuum
breaker
Shutoff
valve
Pressure
gauge
Apply correct thermal
expansion tank-size
per application
Shutoff valves
Shutoff valves
Check valves
Cold w
at
er inle
t
Gas inle
t
Water
filter
Drain
plug
Thermostatic mixing valve
Hot water
supply and
return to
heating coil
System installed with reverse
acting aquastat to shut off fan.
Suggested but not required by
248 CMR
50’-0” maximum distance from
water heater to fan coil.
(Developed length) Not including
coil in heating unit
NSF-61 product
approved pump
Automatic tempering device
must be installed below
the top of the water heater
as per manufacturer’s
recommendations
Piping loop
between water
heater and fan
coil shall be in
compliance with
248 CMR
Tempered water to
plumbing fixtures. Must
meet temperature
requirements of 248 CMR
All water piping should be insulated
in accordance with 780 CMR
(Massachusetts energy code)
Installation Manual
Ball
Valve
Isolation
Valve
Applications
