LAARS Mighty Therm VW (Sizes 2000-5000) - Installation, Operation and Maintenance Instructions - Manual (Page 4)

LAARS Heating Systems
Page 4
1.3 Water Chemistry
Laars equipment is designed for use in a wide
variety of water conditions. The water velocity
maintained in the heat exchanger tubes is kept high
enough to prevent scaling from hard water, and at the
same time, low enough to avoid corrosion from soft
water. Most of the urban areas in the country have
water that is compatible with this equipment. In some
areas a water supply will contain a heavy quantity of
scaling chemicals, or the water may be extremely soft
and corrosive. In rare situations, the water will contain
both scaling chemicals and corrosive chemicals such
as calcium, or sodium chloride. These conditions may
be the result of a nearby well or pumping station, and
the particular condition may not be characteristic of
the entire city water system.
If an installer observes damage from these
conditions to any water handling equipment in the
area, a factory representative should be contacted
immediately for assistance in minimizing maintenance
costs. If erosion is present, the pump impeller can be
replaced to reduce water velocity. If scaling
conditions are bad, tube cleaning maintenance
schedules can be established to prevent tube burn-out
and cracking. Neglecting the problem could mean
serious damage to the heater and water system.
Scaling can be recognized as a layer deposited
on the inner walls of the tubes which reduces the inner
diameter of the tube. Scale can be any color or
texture; smooth or rough, granular or amorphous.
Erosion is generally evidenced by pitting, cavitation,
ridges and “islands” on the inner walls of the tubes.
Where this condition results from extremely soft
water sources, or as a result of a water softening
program, the internal copper surfaces will be
extremely shiny. Other chemicals, such as chlorine or
chlorides in the water, will result in dark surfaces of
erosion.
In areas where the water supply is extremely
corrosive, it is advisable to order the heater with
cupronickel tubes in the exchanger.
Damage from scaling, corrosion, or erosion is
not covered by the warranty.
SECTION 2.
Installation
2.1 Heater Placement
The heater must be placed to provide clearances
on all sides for maintenance and inspection. There
must also be minimum distances maintained from
combustible surfaces.
All heaters must be installed on a non-
combustible flooring. Under no circumstances can
heaters be installed on carpeting.
Base Must Extend Out
Min. 12" On All Sides
Of Heater Frame Metal Plate
20 Ga. Min.
Under Entire
Heater
Concrete Blocks Or Tile
Min. 7" High With 3" Min.
Air Openings
Blocks must provide solid base and be braced
so they cannot slip out of place. Air openings
in blocks must be arranged to provide
unobstructed opening through entire width or
length of base.
Clearance Indoor Outdoor
From (Inches) (Inches)
Top 24 —
Water Conn. Side 24 24
Opposite Side 24 24
Front 48 48
Rear 24 24
Vent 6 —
Table 1 – Minimum Heater Clearances From
Combustible Surfaces.
The National Fuel Code allows a heater to be
placed on other than a non-combustible surface when
such an installation complies with the local codes.
This code specifies the surface under the heater be
protected with hollow masonry no less than 4" thick,
covered with sheet metal at least 20 gauge in
thickness. Such masonry must be laid with ends
unsealed, and joints matched in such a way as to
provide a free circulation of air from side to side
through the masonry (see Figure 2).
Figure 2. Non-Combustible Base.
2.2 Indoor Installation
2.2.1 Combustion Air Supply
1. The heater location must provide sufficient air
supply for proper combustion, and ventilation of
the surrounding area as outlined in the latest
edition of ANSI standard Z223.1 and in Canada,
CAN1-B149 requirement, and any local codes
that may be applicable. Inadequate combustion
air supply may result in incomplete combustion
and consequent sooting of the heat exchanger
and unsafe operation of the heater.