Benchmark 750 – 1000 Boiler User Manual - INTERNATIONAL
CHAPTER 2 – INSTALLATION
OMM-0119_0A
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
Page
17
of
170
GF-130-I
Ph.: 800-526-0288
11/03
/2016
Figure 2-3: Supply and Return Locations
The dual inlet connections allow these units to be configured with a separate cooler return
temperature zone, rather than blending high and low return temperature zones. Utilizing the
dual return capability, these Heating Boilers can take further advantage of the condensing
capabilities. When configured with a lower return temperature zone or AERCO SmartPlates,
thermal efficiency can improve by up to 6% (Based on an 80°F (26.7°C) minimum return water
temperature at full fire. Lower return temperatures are possible which would yield even greater
efficiency gains. The maximum temperature differential across the Heating Boiler’s heat
exchanger is 100°F (55°C).
To use the secondary inlet, pipe the
warmer
return water to the secondary (upper) inlet and the
cooler
return water to the
primary
(lower) inlet. . If the flow through both the primary and the
secondary return is constant, then the combined minimum flows must equal the specified
minimum flow of the Heating Boiler. If the flow through either of the inlet returns is intermittent,
then the minimum flow through one of the return connections must always equal the specified
minimum flow of the Heating Boiler.
If the secondary inlet is not utilized, it may serve as an inspection port. Contact your AERCO
representative for additional information.
1” (254 mm) NATURAL
GAS INLET
BOILER HOT
WATER OUTLET
(SUPPLY)
EXHAUST MANIFOLD
CONDENSATE
DRAIN PORT
AIR INLET
DRAIN VALVE
SECONDARY
WATER INLET
(
WARMER
WATER RETURN)
PRIMARY
WATER INLET
(
COOLER
WATER RETURN)
