Water Piping And Trim; Low Water Cut Off (Lwco) On Hot Water Boilers; Lwco Location - Burnham PVG Installation, Operating And Service Instructions

IV. Water Piping and Trim
Failure to properly pipe boiler may result in improper operation and damage to boiler or structure.
Oxygen contamination of boiler water will cause corrosion of iron and steel boiler components, and
can lead to boiler failure. U.S. Boiler's Standard Warranty does not cover problems caused by oxygen
contamination of boiler water or scale (lime) build-up caused by frequent addition of water.
A.
Design and install boiler and system piping to
prevent oxygen contamination of boiler water and
frequent water additions.
1. There are many possible causes of oxygen
contamination such as:
a. Addition of excessive make-up water as a result
of system leaks.
b. Absorption through open tanks and fittings.
c. Oxygen permeable materials in the distribution
system.
2. In order to insure long product life, oxygen sources
must be eliminated. This can be accomplished by
taking the following measures:
a. Repairing system leaks to eliminate the need for
addition of make-up water.
b. Eliminating open tanks from the system.
c. Eliminating and/or repairing fittings which allow
oxygen absorption.
d. Use of non-permeable materials in the
distribution system.
e. Isolating the boiler from the system water by
installing a heat exchanger.
f. Use properly designed and operating air
elimination devices in water piping.
B.

Low Water Cut Off (LWCO) on Hot Water Boilers

(Optional)
WARNING
DO NOT ATTEMPT to cut factory wires to
install an aftermarket Low Water Cut Off
(LWCO). Only use connections specifically
identified for Low Water Cut Off.
In all cases, follow the Low Water Cut Off
(LWCO) manufacturer's instructions.
A low water cutoff is required to protect a hot water
boiler when any connected heat distributor (radiation)
is installed below the top of the hot water boiler (i.e.
baseboard on the same floor level as the boiler). In
addition, some jurisdictions require the use of a LWCO
with a hot water boiler.
When
WARNING
The universal location for a LWCO on both gas and oil
hot water boilers is above the boiler, in either the supply
or return piping. The minimum safe water level of a
water boiler is at the uppermost top of the boiler; that is,
it must be full of water to operate safely.
The PVG boiler is designed to accept the wiring of the
Safgard Model 1100-H4 LWCO (P/N 100592-01). This
is a probe type LWCO. The factory wiring is designed
to allow simple "Plug-in" installation of the wiring.
A "tee" is commonly used to connect the probe LWCO
to the supply or return piping, as shown below.
Select the appropriate size tee using the LWCO
manufacturer's instructions. Often, the branch
connection must have a minimum diameter to prevent
bridging between the probe and the tee. Also, the run
of the tee must have a minimum diameter to prevent
the end of the probe from touching or being located too
close to the inside wall of the run of the tee.
Ideally, manual shutoff valves should be located
above the LWCO and the boiler to allow for servicing.
This will allow probe removal for inspection without
draining the heating system. Many probe LWCO
manufacturers recommend an annual inspection of the
probe.
Where
What Kind
How to Pipe

LWCO Location

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