Laars Mighty Max VW Series, Installation, Operation And Maintenance Instructions

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LAARS HEATING SYSTEMS
Some jurisdictions may require a backflow
preventer in the cold water line. In such cases, the
temperature and pressure relief valve may discharge
water due to expansion. An expansion tank approved
for potable water will eliminate this condition. Follow
the manufacturer's instructions for installation of the
expansion tank.
2H. Venting and Combustion Air
Information
Provisions for venting and supply of air for
venting and combustion must be done in accordance
with these instructions and applicable requirements of
the latest edition of ANSI Z223.1/NFPA 54. In
Canada, installation must be in accordance with CAN/
CGA B149.1 or .2, and applicable local codes.
There are a variety of ways to provide venting
and combustion air for the VW heater (see Figure 7).
The Mighty Max VW heater is certified as a true
direct vent unit when installed according to the
instructions for horizontal venting and ducted
combustion air. This can be done even if the runs are
vertical.
2I. Top-to-Rear Vent Collar Conversion
The Mighty Max VW heater is shipped with the
vent collar on top of the heater. Follow this procedure
to convert it for rear connection (see Figure 8).
1. Remove the adapter plate from the top panel.
2. On the heater jacket, remove the top panel and
ease its lip from under the edge of the bonnet to
gain access to the flue collector.
3. Remove the vent collar/stack from the flue
collector. Do not damage the vent collar/stack
during removal.
4. Remove the blank plate from the rear of the
heater jacket.
5. Remove the blank plate from the rear section of
the flue collector. Be careful not to lose the
insulation attached to the plate.
6. Apply high temperature sealant and install the
blank plate (previously removed from the rear
section of the flue collector) on top of the flue
collector.
7. Install the blank plate (previously removed from
the rear of the boiler jacket) over the stack
opening on the top panel of the boiler.
8. Apply high temperature sealant (see Table 6) to
vent/collar stack and install on the rear of the
flue collector.
9. Slip the adapter plate over the vent collar/stack
and install it onto the rear heater jacket (see
Figure 8).
2J. Venting
Venting must be in accordance with these
instructions and applicable requirements of the latest
edition of ANSI Z223.1/NFPA 54. In Canada,
installation must be in accordance with the latest
edition of CAN/CGA B149.1 or .2, and applicable
local codes.
2J-1. Vertical Venting - Category I
The Mighty Max VW heater has a “fan-assisted”
combustion system, so vertical vents must be installed
in accordance with the special code requirements for
Category I - Fan-Assisted Appliances. These
requirements can be found in the latest edition of
ANSI Z223.1/NFPA 54, Appendix G, Table 1, and in
Canada, CAN/CGA B149.1 or .2, Amendment No. 1.
These codes permit installation as a single appliance
or in combination with other Category I appliances.
However, there are very important requirements for
minimum and maximum vent diameter and length.
Make sure vertically-vented installations comply with
these codes.
NOTE: If a vent cannot be installed in accordance
with the requirements of these codes, it must be
installed as a horizontal vent, even if it is mainly
vertical.
2J-2. Vertical Venting - Non-Category I
When venting does not meet the code
requirements for Category I - Fan-Assisted Vertical
Vents, it can develop positive pressure. Such venting
must be installed in accordance with this section or
Section 2J-3.
The following requirements must be used for
Non-Category I venting:
1. Laars specified vent pipe material (Table 6) and
sizes (Table 7).
2. Pipe insulation and sealing tape.
Term Description
Pipe Type 304, Type 316, or 29-4C
stainless steel, 24 gauge minimum
Joint Sealing 3M Type 433 sealing tape with 400°F
(204°C) rating or high temperature
silicone sealer with 500°F (260°C)
rating, Dow No. 736
Insulation R5 minimum with protective cover
Table 6. Required Horizontal Venting Material.