Owner's Manual

34
3.6.1.1 Use Figure 3-13 to calculate the volume of the
modules.
Example: Find the volume of water in four 806H
modules.
Solution: From Figure 3-13 nd that the water
volume of one 806H is 13.9 gallons and multiply by
the number of modules:
13.9 x 4 = 55.6 gallons in the modules.
3.6.1.2 The water side of terminal units must be known in
order to determine their volume. Tubular units such
as baseboard, commercial nned tube, convectors
and fan coils can be computed by knowing the
length and size of the tubes.
Example: Find the water volume in 528 ft. of 1¼”
copper dual tiered commercial nned tube.
Solution: From Figure 3-8 obtain the value of .065
gal/ft. for 1¼” copper and multiply by 528 ft. and by
2 tiers:
0.65 gal/ft x 528 ft x 2 tiers = 68.6 Gallons in the
Finned Tube.
3.6.1.3 From the above examples the total volume of the
system can be added:
Volume of piping = 29.3 Gal.
+ Volume of modules = 55.6 Gal.
+ Volume of Finned Tube = 68.6 Gal.
Total Volume of System = 153.5 Gal.
3.6.2 Conventional compression tanks can be sized by using
Figures 3-9 and 3-10. Enter Figure 3-9 in the left
hand column at the water volume of the system, move
across to the right to the maximum water temperature
of the system and read the uncorrected tank size.
To nd the correction factor, enter Figure 3-10 in the
left hand column of the initial ll pressure and move
across to the right to column for the system pressure
increase and read the tank correction factor. Multiply
the uncorrected tank size by the correction factor to
nd the nal tank size.
Example: Find the conventional compression tank
size for a system having a water volume of 153.5
gallons, a design water temperature of 240°F, a 50 psi
relief valve and a system height of 30 Ft.
Solution:
1) Enter Figure 3-9 in the left hand column and move
down to 200 gallons (which is the next largest
value to 153.5 gallons). Read across to the column
for 240 design water temperature and read 38
gallons uncorrected tank size.
2) Find the initial ll pressure by multiplying the
system height by 0.433:
30 x 0.433 = 13 psi
3) Enter Figure 3-10 in the left hand column and
move down to 12 psi ll pressure (closest to 13
psi). Move across to the column headed 40 psi
pressure increase (closest column to 40 psi minus
13 psi) and read a correction factor of 0.63
4) Multiply 0.63 x 38 Gal. = 24 gallons corrected tank
size.
5) Select a conventional compression tank size of at
least 24 gallons. In some cases, greater accuracy
may be obtained by interpolation in Figures 3-9
and 3-10.
3.6.3 Diaphragm type compression tanks can be sized by
using Figures 3-11 and 3-12. Find the expansion
factor for water at the design water temperature from
Figure 3-11. Multiply that expansion factor by the
volume of the system to obtain the acceptance volume
of the compression tank.
Find the tank volume by dividing the acceptance
volume by the acceptance factor from Figure 3-12.
Example: nd the diaphragm type tank size for the
same system as in 3.6.2 above.
Solution:
1) From Figure 3-11 at 240°F design temperature read
an expansion factor of .0518.
2) Multiply the system volume by the expansion
factor:
Acceptance volume = 153.5 Gal x .0518 = 8
gallons
3) Enter gure 3-12 at a ll pressure of 13 psi and
a nal pressure of 50 psi and read the acceptance
factor of 0.58.
4) Tank volume = 8 gallons ‘ 0.58 = 14 gallons
5) Select a diaphragm type tank having a minimum
acceptance volume of 8 gallons and a tank volume
of at least 14 gallons.
3.7 LOW WATER CUTOFF—On each modular install-
ation at least one low water cutoff is required. If,
as recommended in 3.3, modules are installed with
shutoff valves in their respective supply and return
piping to the manifold then each module will require a
dedicated LWCO. Otherwise, a system LWCO will be
required.
3.7.1 If a system LWCO is to be used, such as shown in
Figure 3-1 or 3-2, it must be installed on the return
main at an elevation higher than the modules and
ll valve. The pipes connecting from the main to
the system LWCO must be teed into the return main
using the shortest possible 1” pipe and fewest ttings.
See Figure 3-1 or 3-2. Do not install valves between
the return main and the system LWCO. If for any
reason, the elevation of a module is different from
another module in the group, the system LWCO must
be installed above the module having the highest
elevation.
3.7.2 If dedicated LWCO’s are to be used they must be
installed between each module and its respective
shutoff valve and at an elevation higher than the
module and its ll valve. A probe style LWCO
is available as an option and its recommended
installation location is in the module’s supply riser
to the manifold as depicted in Figures 3-2 and 3-3.
Do not install any valve between the module and its
respective LWCO.