Ap
plication
s
UP Series
5
33
Comfort System
The Comfort System uses a patented Comfort Valve®
and pump to provide instant availability of hot water at
the point of use.
Operation
The Comfort Valve® is installed at the fixture furthest
away from the hot-water tank. With a built-in timer, the
pump allows hot water to circulate along the loop
through the valve using the cold-water side as a return
line. As the temperature rises to 100 °F (38 ° C), the
valve closes directing hot water to the tap, thus
resulting in a constant availability of hot water.
Savings
The Comfort System saves up to 16,000 gallons
(60,566 liters) of water per year and per household
(based on average modern household usage) and
uses less energy than a 25 W light bulb.
Applications
• Domestic hot-water recirculation systems in single-
and two-family houses.
Pumped liquids
• Domestic hot water
• Potable and non-potable water
Fig. 7
Comfort System
Motor
• Insulation class: F.
• Power consumption: 25 W.
• Voltage: 115 V.
• Current 0.23 A.
• Phase: 1.
Grundfos Comfort Valve body materials
Ambient and liquid temperatures
Liquid temperature: 36 °F (2 °C) to 150 °F (66 °C).
It is recommended to keep the operating temperature
as low as possible (e.g. 140 °F (60 °C)) to avoid
calcium precipitation.
The ambient temperature should always be lower than
the liquid temperature, as otherwise condensation may
form in the stator housing.
Maximum system pressure
145 psi (10 bar).
Fig. 8
Performance curve for the Comfort System
TM
03 91
26 340
7
Description
(UP open systems)
Material
Inlet cone, bearing plate, bearing
retainers, rotor can, rotor
cladding, shaft retainer
Stainless steel
Volute retainer (SU & SF models)
and stator housing
Aluminium
Shaft, upper and lower radial
bearings
Aluminium oxide ceramic
Thrust bearing
Carbon bearing and EPDM
retainer
Pump housing (volute)
Silicon bronze C875 or stainless
steel 300 series.
O-ring and gaskets
EPDM (ethylene propylene
rubber)
Impeller
PES composite (30 % glass-filled)
Terminal box
Noryl® with EPDM gasket
Description
Trade name
Material
Springs, pins, screens 300 Series
Stainless steel
Valve body
Ryton
PPS
Thermal actuator
body
300 Series
Stainless steel
Check valve O-ring
EPDM
Check valve body
Acetal
Check valves plunger
Thermoplastic
TM
0
3
5
547
3
806
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Q [US GPM]
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
[ft]
H
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Q [m³/h]
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
[m]
H
UP15-10SU7P/TLC
60 Hz
http://waterheatertimer.org/Water-heater-recirculation-system.html
