LAARS HEATING SYSTEMS
Page 8
1H-1. Common Venting System
When an existing boiler is removed from a
common venting system, the common venting system
is likely to be too large for proper venting of the
appliances remaining connected to it.
At the time of removal of an existing boiler, the
following steps shall be followed with each appliance
remaining connected to the common venting system
placed in operation, while the other appliances
remaining connected to the common venting system
are not in operation.
1.
Seal any unused openings in the common
venting system.
2.
Visually inspect the venting system for proper
size and horizontal pitch and determine there is
no blockage or restriction, leakage, corrosion and
other deficiencies which could cause an unsafe
condition.
3.
Insofar as it is practical, close all building doors
and windows and all doors between the space in
which the appliances remaining connected to the
common venting system are located and other
spaces of the building. Turn on clothes dryers
and any appliance not connected to the common
venting system. Turn on any exhaust fans, such
as range hoods and bathroom exhausts, so they
will operate at maximum speed. Do not operate a
summer exhaust fan. Close fireplace dampers.
4.
Place in operation the appliance being inspected.
Follow the lighting instructions. Adjust
thermostat so appliance will operate
continuously.
5.
Test for spillage at the draft hood relief opening
after 5 minutes of main burner operation. Use the
flame of a match or candle, or smoke from a
cigarette, cigar or pipe.
6.
After it has been determined that each appliance
remaining connected to the common venting
system properly vents when tested as outlined
above, return doors, windows, exhaust fans,
fireplace dampers and any other gas burning
appliance to their previous conditions of use.
7.
Any improper operation of the common venting
system should be corrected so the installation
conforms with the National Fuel Gas Code,
ANSI Z223.1. When resizing any portion of the
common venting system, the common venting
system should be resized to approach the
minimum size as determined using the
appropriate tables in Appendix G in the National
Fuel Gas Code, ANSI Z223.1.
1I. Water Piping of Boiler System
Figure 5 shows ‘typical’ plumbing installations.
Be sure to provide unions and gate valves at the
boiler inlet and outlet so it can be isolated for service.
Check local codes for specific plumbing requirements
before beginning the installation.
An ASME pressure relief valve is supplied on all
JV boilers, and is pre-set at 30 PSI. The valve outlet
piping must discharge to a drain. Under no
circumstances should the relief valve piping be a
closed circuit.
A pressure reducing valve (automatic feed) must
be used to maintain system at constant proper pressure
(see Figure 6). Supply properly installed purge valves
to eliminate air from each circuit.
A drain valve is supplied with the boiler, and can
be found in the plastic bag shipped with each boiler.
This valve is to be installed on the lower right side of
the boiler, see Figure 4, and is used for draining the
unit. To drain the boiler completely, open the drain
valve and remove the two drain plugs located on
the lower left side of the boiler.
Be sure to include air vent devices located at the
highest point in the system to eliminate trapped air,
and an air elimination device near the outlet side of
the JV boiler. Manual vent valves are recommended.
Hot water piping should be supported by suitable
hangers or floor stands, NOT by the boiler. Due to
expansion and contraction of copper pipe,
consideration should be given to the type of hangers
used. Rigid hangers could transmit noise through the
system caused by the piping sliding in the hangers. It
is recommended that padding be used when rigid
hangers are installed.
Gas piping should also be supported by suitable
hangers or floor stands, not the boiler.
A properly sized expansion tank must be
included in the system. Laars offers an aircharged
diaphragm-type expansion tank, with an automatic
feed valve, which includes a pressure regulator set at
12 psig. The part numbers are:
Less Than 20 Gallons in System
A0066800
20 to 45 Gallons in System
A0066900
1I-1. By-pass Piping
The following information and suggestions are
made on by-pass piping as it affects the temperature
rise at the boiler. A boiler temperature rise must be
taken on all JV boiler installations. If the temperature
rise exceeds 30°F (-1°C), it is an indication that the
boiler is not receiving adequate water flow. Check the
pump for any obstruction, replace the pump with a
larger size where necessary, or install a system by-
pass as indicated in Figures 6 and 7.
On JV sizes 125, 160 and 225 with a multiple
zone system, a by-pass is required to ensure proper
flow in addition to properly sized circulator and piping
system.
