Calumet GSA Manual - Install Piping
GSA Gas-Fired Steam Boilers – Boiler Manual
10
Part Number 550-110-738/0703
3
Install piping
continued
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 residential
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 6, this page, for suggested reservoir pipe
size. Install as shown in Figure 7, below.
For larger systems (as noted in Table 6), 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 7 to size boiler feed systems. See page 7, Table 4, 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.
Condensate return
Figure 7
Recommended piping for parallel-flow
systems with optional reservoir pipe
During operation, this valve may discharge large
amounts of steam and/or hot water. Therefore, to
reduce the potential for bodily injury and property
damage, a discharge line MUST be installed that:
• Is connected from the outlet to a safe point of
discharge with no intervening valve.
• Allows complete drainage of both the valve and the
discharge line.
• Is independently supported and securely anchored
so as to avoid applied stress as possible.
• Terminates freely to atmosphere where any
discharge will be clearly visible and is at no risk of
freezing.
• Is, over its entire length, of a pipe size equal to or
greater than that of the valve outlet.
Use only schedule 40 metal pipe for discharge. (Do
not use schedule 80, extra strong or double strong
pipe or connections.) DO NOT CAP, PLUG OR
OTHERWISE OBSTRUCT DISCHARGE PIPE
OUTLET! If discharge is piped upward, a condensate
drain must be provided in the elbow below the vertical
pipe to prevent condensate from returning into the
valve. Failure to comply with these instructions will
cause a dangerous spray of hot water and steam
that would cause severe personal injury or death.
Relief valve
continued
Table 7
Boiler feed system sizing
Boiler
model
number
I=B=R
gross
output
(pounds
steam
per hour)
Conden-
sate
(gallons
per hour)
Minimum condensate receiver
capacity gallons for boiler
steaming times (minutes) of:
(note 1)
Suggested
feed pump
capacity
(GPM @
15 PSI)
(note 2)
15 min. 30 min. 45 min. 60 min.
GSA-075
63
8
2
4
6
8
0.2
GSA-100
81
10
3
6
9
12
0.3
GSA-125
102
12
4
7
11
14
0.4
GSA-150
122
15
5
9
14
18
0.5
GSA-175
142
17
5
10
15
20
0.6
GSA-200
163
20
6
12
18
24
0.7
GSA-250
203
24
7
14
22
29
0.8
Notes
1. Maximum time to when condensate returns to boiler.
2. If pump capacity exceeds capacity shown, pump can be throttled with globe or
ball valve.
Table 6
Reservoir pipe sizing
Boiler
model
number
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)
GSA-075
75
1
1
1½
1½
Use boiler feed
system
GSA-100
100
1
1
2
2
GSA-125
125
1¼
1¼
2½
2¼
GSA-150
150
1½
1½
3
2½
GSA-175
175
1¾
1¾
Use boiler feed system
GSA-200
200
2
2
GSA-250
250
2½
2¼
Designed full capacity steaming time of modern boilers is 10 minutes.