Pump Capacity; Tailpipe Flow; Figure 15: Vacuum Loss Curve For 4" Shared Tailpipe; Table 2: Pump Capacity - Roberts Gorden CoRayVac CRV-B-2 Design Manual

CRV-S D M
ERIES ESIGN ANUAL

5.2 Pump Capacity

The flow unit capacity of the pump is indicated on
Page 14, Table 2, as a function of installed altitude.
When the CRV-Series system is designed in accor-
dance with this set of instructions and is in proper
operating condition, a vacuum from 2-3" w.c. will be
obtainable at each end vent (i.e. at all burners).

Table 2: Pump Capacity

Installed Altitude
Feet Above Meters Above
Sea Level Sea Level
' '
0 - 2000 0 m - 609 m
' '
2001 - 3000 610 m - 914 m
' '
3001 - 4000 915 m - 1219 m
' '
4001 - 5000 1220 m - 1524 m
' '
5001 - 6000 1525 m - 1828 m
' '
6001 - 7000 1829 m - 2134 m
' '
2135 m - 2438 m
7001 - 8000
' '
2439 m - 2743 m
8001 - 9000
There are a number of design requirements which, if
not met, will reduce the vacuum obtainable and
thereby the effective flow capacity of the pump. These
include:
• Minimum Length of Tailpipe - If less than the
minimum length of tailpipe is provided per radiant
branch, there will be insufficient cooling of the com-
bustion gases and improper operation of the pump.
• Line Loss Check for Tailpipe is applicable to
sections of tailpipe which are common to two or
more radiant branches (i.e. shared lengths). See
Page 14, Figure 15.
• Excessive back pressure on discharge line of
pump can be caused by partial blockage or too
much flow for length. See Section 5.3.1
• More than maximum number of burners or flow
units per radiant branch. See Page 14, Table 2.
• Excessive number of elbow or tee fittings
which increases vacuum loss.

5.3 Tailpipe Flow

Excessive flow loading in a single section of tailpipe
can cause low vacuum and lower effective pump
capacity. For the pump to develop the proper vacuum,
the length of tailpipe must not be excessive for the
14
Maximum Flow Units
EP-200 EP-300
EP-100
Series Series
66 112 224
63 105 215
60 100 206
57 95 197
54 90 188
51 84 180
48 80 170
45 75 161
number of flow units carried in the tube.
See Figure 15. Readings for length and flow when
plotted on the graph must fall on OK side to avoid
excessive vacuum losses.
FIGURE 15: Vacuum Loss Curve for 4" Shared
Tailpipe
NOTE: For 6" (15 m) tailpipe, length is limited to a
maximum of 100' (30 m). See Page 16, Section 6.3
for more details.
Lengths shown include allowance for 1 elbow every
50' (15 m); deduct 15% of length for each additional
elbow used per 50' (15 m) length.
5.3.1 Pump Exhaust Length Requirements
The tube length on the exhaust side of the pump is
considered excessive if not within the following condi-
tions:

Table 3: Pump Exhaust Requirements

Pump Series Exhaust Tube Length Exhaust Tube Diameter
EP-100 Up to 25' (7.6 m)
EP-100 Up to 50' (15 m)
EP-200 Up to 10' (3 m)
EP-200 Up to 25' (7.6 m)
EP-200 Up to 50' (15 m)
EP-300 Up to 10' (3 m)
EP-300 Up to 25' (7.6 m)
EP-300 Up to 50' (15 m)
4" 3 Elbows
5" 3 Elbows
4" 0 Elbows
5" 3 Elbows
6" 3 Elbows
6" 1 Elbows
7" 3 Elbows
8" 3 Elbows