Specification

Selection
This Quick Reference Selection Guide may be used as an alternative to
using a formula to determine the correct expansion tank for the system.
This table is based upon a relief valve setting of 150psi (10.3 bar),
and a maximum of 50°F temperature rise.
To select the correct model DET series tank, simply go the supply pres-
sure equal to the system supply pressure (for pressures between those
shown use next highest supply pressure shown), read across the chart to
the correct tank as indicated by the water heater capacity (for capacities
between those shown, use next highest capacity).
To accommodate the thermal expansion required for higher temperature
and/or higher pressure systems, multiple tanks may be used. Please
contact the factory for sizing information.
Materials
Diaphragm: Butyl rubber
Inlet Connection: Brass (DET-35-M1: Stainless Steel)
Water
Meter
Watts
Shutoff
Watts
Backflow
Preventer
Watts
Pressure
Gauge
Watts DET
Expansion
Tank
Watts
Service
Check
Valve
Watts
Vacuum
Relief
Valve
Hot Water to
dishwasher
and washing
machine
Watts
Tempering
Valves
Tempered Water
Watts
Seismic
Straps
Watts
Water
Heater
Stand
Watts T&P
Relief Valve
Watts
Drain Tube
Watts
Water
Pressure
Reducing
Valve
Cold
Technical Information
Description DET-5-M1 DET-12-M1 DET-20-M1 DET-35-M1
Max. Pressure - PSI 150 150 150 150
Max. Temp. - °F 200 200 200 200
Tank Volume - Gal. 2.1 4.5 8.5 14.00
Tank Acceptance - Gal. .85 1.8 3.2 5.6
Air Pre-charge - PSI 20 20 20 20
Connections Size - Inches
3
⁄4 Male
3
⁄4 Male
3
⁄4 Male 1 Female
Diameter - Inches 8.5 10.0 12.5 16.0
Length - Inches 11.5 15.0 19.2 21.7
Weight - Lbs. 7 10 15 32
Acceptance Volume
Air Side Water Side Volume
Pre-pressure at 150psi (gallons)
(psi) DET-5-M1 DET-12-M1 DET-20-M1 DET-35-M1
20 1.500 2.801 7.102 10.69
40 1.272 2.208 5.882 9.17
60 .996 2.076 4.705 7.59
80 .720 1.716 4.009 6.07
ES-DET-M1 0910 © Watts, 2009
USA: 815 Chestnut St., No. Andover, MA 01845-6098; www.watts.com
Canada: 5435 North Service Rd., Burlington, ONT. L7L 5H7; www.wattscanada.ca
Water Safety & Flow Control Products
SUPPLY
PRESSURE
(PSIG)
WATER HEATER (GALLONS)
20 30 40 50 80 100 120
40
50
55
60
70
80
90
100
110
120
DET-5-M1 DET-20-M1
DET-12-M1 DET-35-M1
Multiple tanks required - consult factory