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Figure 20 Recommended piping for parallel-flow systems
with optional reservoir pipe
Part Number 550-142-303/1120
19
EG
/
PEG sEriEs 6
•
EGH sEriEs 5 Gas-firEd boilErs — boilEr manual
Connect piping – steam boilers (continued)
Table 9 Boiler feed system sizing
Condensate return
Modern steam boilers are designed to steam for less time than
older, larger boilers. When replacing an older steam boiler the
system condensate return time may be longer than the steaming
time. This could cause the following problems:
1. Boilers fitted with an automatic water feed could overfill.
2. Units fitted with only a low water cutoff would shut down
and cycle while waiting for condensate to return.
Following is a simple method for determining whether or not a
reservoir pipe is required to lengthen steaming time for a resi-
dential installation:
1. Disconnect condensate return line at existing boiler.
2. Heat
boiler and allow to steam for 10 minutes. Turn off boiler.
3. Measure length of time from when boiler started to steam to
when condensate begins to return through condensate line.
4. Measure length of time from when condensate begins to
return to when it stops returning. Divide this time by 2.
5. Add time measured in step 3 to time calculated in step 4. This
sum is the average time required for condensate to return to
the boiler.
6. If this total time is 10 minutes or less, no reservoir pipe is
needed.
If total time for condensate to return to boiler (from step 5) is
more than 10 minutes, a reservoir pipe (or boiler feed system) is
recommended. See Table 8 and Figure 20 for suggested reservoir
pipe size. Install as shown in Figure 20.
For larger systems (as noted in Table 8), use a boiler feed system
with a condensate tank and feed pump. You will have to install a
low water cutoff/pump control on the boiler to operate the pump.
Use Table 9 to size boiler feed systems. See Figure 5, page 10, for
tapping locations. (The use of a combination condensate tank and
float-controlled condensate return pump is not recommended.)
For most residential installations a reservoir pipe may be all that
is necessary to ensure proper operation.
Boiler
model
number
Max.
boiler
gross
output
Time from initial steaming to average condensate return
(boiler steaming capacity based on 970 Btu per pound of steam)
15 minutes 20 minutes 30 minutes
MBH gallons
pipe
length
(feet)
gallons
pipe
length
(feet)
gallons
pipe
length
(feet)
EG/PEG-30
64
¾ ¾ 1 ½ 1 ½ 3 2 ½
EG/PEG-35
85
EG/PEG-40
106
1 ¼ 1 ¼ 2 ½ 2 ¼
Use boiler feed
system
EG/PEG-45
127
EG/PEG-50
148 1 ½ 1 ½ 3 2 ½
EG/PEG-55
169 1 ¾ 1 ¾
Use boiler feed
system
EG/PEG-65
201 2 ¼ 2 ¼
EG-75
237 2 ½ 2 ½
EGH-85
243 2 ½ 2 ½
EGH-95 up Not recommended –– Use boiler feed system if needed
Designed full capacity steaming time of modern boilers is 10 minutes.
Table 8 Reservoir pipe sizing
Boiler
Model
Gross
Output
Pounds
Steam
Per
Hour
Gallons
Conden-
sate
Per
Hour
Minimum Condensate
Receiver Capacity (Gal.)
Recom-
mended
Maximum
Minutes of boiler
operation:
Feed
Pump
Capacity
GPM
*
15 30 45 60
EG/PEG-30
62 7 ½ 2 5 7 10 0.3
EG/PEG-35
82 10 3 7 10 13 0.3
EG/PEG-40
103 12 ½ 4 8 12 17 0.4
EG/PEG-45
124 15 5 10 15 20 0.5
EG/PEG-50
145 17 ½ 6 12 17 23 0.6
EG/PEG-55
166 20 7 13 20 27 0.7
EG/PEG-65
198 25 8 17 25 33 0.8
EG-75
234 29 ½ 10 20 29 39 1.0
EGH-85
253 29 10 19 29 39 1.0
EGH-95
290 33 ½ 11 22 33 45 1.1
EGH-105
325 37 ½ 12 25 37 50 1.3
EGH-115
361 41 ½ 14 28 41 55 1.4
EGH-125
398 46 15 31 45 61 1.5
*
If pump capacity exceeds capacity shown, pump can
be throttled with globe or ball valve.
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