General Piping Information; System Water Piping Methods; Circulator Pumps - Heat Transfer MODCON VWH 300 LP Installation & Maintenance

PART 5: BOILER PIPING
B. GENERAL PIPING INFORMATION
NOTICE
The Mod Con Boiler control module uses
temperature sensors to provide both high limit
protection and modulating temperature control.
The control module also provides low water
protection by sensing the water flow through
the flow switch on the heat exchanger. Some
codes/jurisdictions may require additional
external controls.
C. SYSTEM WATER PIPING METHODS
Expansion tank
1. Ensure that the expansion tank size will
handle boiler and system water volume and
temperature. Allow for boiler, piping and
storage tank:
Boiler Water Volume
Mod Con 300 VWH
Mod Con 500 VWH
Mod Con 850 VWH
CAUTION
Undersized expansion tanks cause system
water to be lost from relief valve. Eventual
boiler failure can result due to excessive make-
up water addition. This type of failure is NOT
covered by warranty.
2. The expansion tank must be located as
shown in Boiler Piping Part 5 or following
recognized design methods. See tank
manufacturer's instructions for details.
Always install an expansion tank designed
for potable water systems.
15
GAS-FIRED HOT WATER SUPPLY BOILER
(CONTINUED)
2.9 Gallons
4.2 Gallons
5.8 Gallons
D. CIRCULATOR PUMPS
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CAUTION
DO NOT use the boiler circulator in any location
other than the ones shown in this manual. The
boiler circulator is selected to ensure adequate
flow through the Mod Con Boiler. Failure to
comply could result in unreliable performance
and nuisance shut downs from insufficient flow.
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WARNING
Plumbing of this product should only be done
by a qualified, licensed plumber in accordance
with all local plumbing codes.
The Mod Con VWH is designed to be connected
to a storage tank to supply domestic hot water.
Heat Transfer Products has available storage
tanks that are 80/119/175 gallon size storage
tanks constructed in either Stainless Steel or
Glass lined construction. These storage tanks will
be directly connected to the Mod Con VWH
supply and return connection. Connect the cold
water supply to both the storage bottom port and
the supply side of the Mod Con VWH (shown in
Piping details, this section) It is important that you
install a flow check on the supply line of Mod Con
VWH before you connect feed line to the storage.
This will allow the cold feed to flow through the
storage tank first and not the Mod Con VWH. It is
recommended that you install shut off valves on
the cold feed line for ease of future service. If
there is a back flow preventer, or any type of no
return valve in the system, then you must install
an additional tee for a suitable potable hot water
expansion tank. Connect the Storage tank return
line to the return connection located on the Mod
Con VWH (shown in Piping details, this section).
Then connect your hot water outlet located on
the storage tank to your hot water plumbing lines.
Boiler Manual