Connecting Supply & Return Piping; Boiler Connections; Primary-Secondary Piping; Additional Supply And Return Piping - Watts AERCO Modulex EXT Series Technical Application Manual

Modulex EXT Series Piping
CONNECTING SUPPLY & RETURN PIPING
SECTION 5: CONNECTING SUPPLY & RETURN PIPING

5.1. BOILER CONNECTIONS

Upon delivery, the various models of Modulex EXT boilers are configured with connections for water, gas,
air intake, and flue exhaust. Note that references to right-hand or left-hand orientation refer to the right-
hand or left-hand side when viewed facing the front of the boiler. Some of these connections may be
changed from one side to the other. Refer to section 5.4 for a description of where side connections are
located, which connection locations may be changed, and the instructions for performing the changes.

5.2. PRIMARY-SECONDARY PIPING

Primary-secondary piping must be utilized. This can be accomplished by using a common pipe (see
Figure 13, 14, 17 and 18) or a hydraulic separator (see Figure 15, 16, 19 and 20). Primary – secondary
piping decouples the boiler loop from the system loop, making it independent from system loop pressure
fluctuations associated with opening/closing of zone valves or 3-way valves.

5.3. ADDITIONAL SUPPLY AND RETURN PIPING

(PER ANSI Z21.13A)
When used in connection with a refrigeration system, the boiler must be installed so the chilled medium is
piped in parallel with the boiler with appropriate valves to prevent the medium from entering the boiler.
The boiler piping system of a hot water boiler connected to heating coils located in air handling units
where they may be exposed to refrigerated air circulation must be equipped with flow control valves or
other automatic means to prevent gravity circulation of boiler water during the cooling cycle.

5.4. CHANGING RIGHT-HAND CONNECTIONS TO LEFT-HAND

5.4.1. Modulex Light Commercial Models EXT 450 2S, 600 2S, 800 2S & 1100 2S
Light Commercial size MODULEX EXT boilers are delivered with all connections installed, (i.e. cold/hot
water flow & return, gas, and exhaust outlet) on its RIGHT-HAND side. However, these connections may
be relocated in the positions listed below and as shown below.
Water Flow:
Water Return:
Gas Supply:
Exhaust Manifold: Left, right, or rear.
Air Intake:
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Application Guide
Left or right.
Left or right.
Left or right.
Left (only)
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Phone: 800-526-0288
Blauvelt, NY 10913 TAG-0099