Figure 49
Rinnai Tankless Water Heater Installation and Operation Manual
59
COMBINATION SPACE HEATING/POTABLE WATER SYSTEM
(For Use In Commonwealth of Massachusetts)
Combination Space Heating/Potable W
ater System
All water piping should be insulated in accordance with 780 CMR (Massachusetts Energy
Code)
Expansion
Tank
Check V
alve with 1/8in. Hole
Drilled in Clapper Optional
Cold W
ater Supply
Min. 2' developed length
Type L
copper from water heater
Check V
alve
Automatic
Tempering Device Must be
installed below the top of the water heater as per manufacturer's recommendations.
Tempered water to plumbing fixtures. Must meet temperature requirements of 248 CMR.
Hot W
ater
Supply and
Return to Heating Coil
Electronically controlled pump timer
. Activates
every 6 hours for 60 seconds. Wire to product
approved
pump.
(or built-in pump)
100'-00" maximum distance from water heater to fan coil and back. (Developed length) not including coil in heating unit.
Piping loop between water heater and fan coil shall be in compliance with 248 CMR.
Hot W
ater Coil
Check V
alve
Air Handler
System installed with reverse acting aquastat to shutoff fan. Suggested but not required by 248 CMR.
Gas Supply
W
ater Heater
Use Only in Commonwealth of Massachusetts
Product
Approved W
ater Heater
Shut Off V
alve
NSF-61 Product Approved Pump