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CEMENT
The cement should be a bodied cement of approximately 500 to 1600
centipoise viscosity containing 10-20% (by weight) virgin PVC material
solvated with tetrahydrofuran (THF). Small quantities of dimethyl formamide
(DMF) may be included to act as a retarding agent to extend curing time.
Select the proper cement; Schedule 40 cement should be used for Schedule
40 pipe. Never use all-purpose cements, commercial glues and adhesives
or ABS cement to join PVC or CPVC pipe and fittings.
SAFETY PRECAUTION: PRIMERS AND CEMENTS ARE EXTREMELY
FLAMMABLE AND MUST NOT BE STORED OR USED NEAR HEAT OR
OPEN FLAME. ALSO, USE ONLY IN A WELL-VENTILATED AREA.
CONTROLS AND SWITCHES
All models are provided with four pressure switches. These switches are
essential to the safe and proper operation of the unit. All switches are wired in
series. The controller is set up to shut the unit down whenever there is a failure of
any of the switches. It is important to understand the purpose of each switch.
BLOWER PROVER SWITCH
(SEE FIGURE 12)
The Blower Prover Switch is provided on the heater to verify that the fan is
operating. It is a positive pressure switch whose electrical contacts are normally
open. When the fan increases the pressure in the burner, the pressure switch will
allow the electrical contacts to close. The pressure switch is connected to the burner
tap by a piece of tygon tubing. This tubing must be connected in order for the switch
to change the electrical contacts. The controller requires that the electrical contacts
on this air flow switch be open before it will allow the blower to come on.
BLOCKED OUTLET PROVER SWITCH
(SEE FIGURE 12)
The Blocked Outlet Prover Switch is set up to shut the unit off when a build-up
of positive pressure in the exhaust vent pipe occurs. This switch is a positive
pressure switch that requires an increase in pressure to change the electrical
contacts from normally closed to open. When this switch prevents the unit from
igniting, most likely the exhaust is blocked by some means Check to see if the
condensate is allowed to flow freely from the exhaust elbow and for obstructions
in the exhaust venting and exhaust vent terminal. Also verify that there is no more
than fifty equivalent feet (15.2 m) of three inch PVC vent pipe on the exhaust.
BLOCKED INLET PROVER SWITCH
(SEE FIGURE 12)
The Blocked Inlet Prover Switch is set up to shut the unit off when a build-up
of negative pressure in the intake vent pipe occurs. This switch is a negative
pressure switch that requires an increase in negative pressure to change the
electrical contacts from normally closed to open. The switch is connected to the
pressure tap on the PVC flange connected to the inlet of the blower. When this
switch prevents the unit from igniting, most likely the intake is blocked by some
means. Check to see if there is no more than fifty equivalent feet (15.2 m) of
three inch PVC vent pipe on the intake. Also verify that the intake and intake vent
terminal is free of obstructions that may prevent air from entering the unit.
FIGURE 12.
LOW GAS PRESSURE SWITCH
The Low Gas Switch (LGS) is a single-pole, normally open pressure switch
that will close its contacts when a rising pressure of 5.0 in. (1.25Kpa) W.C.
is encountered. The contacts will open when the pressure falls below the
fixed set point of 4.8"WC (1.18Kpa) for natural gas models and 8.5"WC
(2.08Kpa) for propane models. The LGS monitors the gas supply pressure
to the heater. If the gas supply falls below 5.0 in. (1.25Kpa) W.C., the main
burner is extinguished (if heater is running) or the heater will not start up.
ON/OFF SWITCH
The ON/OFF Switch is a single-pole, single-throw rocker switch. This switch
provides 120V from the line source to the heater.
THE WATER HEATER IS POLARITY SENSITIVE. BEFORE APPLYING
ELECTRICITY TO THIS HEATER BE CERTAIN THAT SUPPLY NEUTRAL
WIRE TO GROUND CHECK INDICATES ZERO VOLTAGE.
HOT SURFACE IGNITER
The Hot Surface Igniter is a device that ignites the main burner by high
temperature (>1800°F or >982°C). When 120VAC is applied to the igniter,
sufficient heat is generated to ignite the main burner. Although improvements
have been made to strengthen the igniter, it is still fragile and care must be
taken when handling the igniter to prevent breakage.
GAS PIPING
Contact your local gas service company to ensure that adequate gas service
is available and to review applicable installation codes for your area.
Size the main gas line in accordance with Table 3. The figures shown are
for straight lengths of pipe at 0.5" (125Pa) W.C. pressure drop, which is
considered normal for low pressure systems Note that fittings such as elbows
and tees will add to the pipe pressure drop.
DO NOT USE FLEXIBLE GAS PIPING.
TABLE 3. MAXIMUM CAPACITY OF PIPE IN CUBIC FEET OF GAS PER HOUR
(Based upon a Pressure Drop of 0.5") Water Column and 0.6 Specific
Gravity Gas and max. gas pressure of 0.5 psig)
LENGTH
NORMAL IRON PIPE SIZES (INCHES)
IN
FEET
1/2" 3/4"
1"
10
175
360
680
20
120
250
485
30
97
200
375
40
82
170
320
50
73
151
285
60
66
138
260
70
61
125
240
80
57
118
220
90
53
110
205
100
50
103
195
125
44
93
175
150
40
84
160
175
37
77
145
200
35
72
135
LENGTH
NORMAL IRON PIPE SIZES (INCHES)
IN
METERS 1/2" 3/4"
1"
3.0
51
105
199
6.1
35
73
142
9.1
28
59
110
12.2
24
50
94
15.2
21
44
83
18.3
19
40
76
21.3
18
37
70
24.4
17
35
64
27.4
16
32
60
30.5
15
30
57
38.1
13
27
51
45.7
12
25
47
53.3
11
23
42
61.0
10
21
40
13
(SEE FIGURE 12)
CAUTION
CAUTION
INPUT IN THOUSANDS BTU/HR
1 1/4" 1 1/2"
2"
2 1/2"
3"
1400
2100 3960 6300
11000 23000
950
1460 2750 4360
7700 15800
770
1180 2200 3520
6250 12800
660
990
1900 3000
5300 10900
580
900
1680 2650
4750
530
810
1520 2400
4300
490
750
1400 2250
3900
460
690
1300 2050
3700
430
650
1220 1950
3450
400
620
1150 1850
3250
360
550
1020 1650
2950
325
500
950
1500
2650
300
460
850
1370
2450
280
430
800
1280
2280
INPUT IN KW
1 1/4" 1 1/2"
2"
2 1/2"
3"
410
615
1160 1845
3221
278
428
805
1277
2255
225
346
644
1031
1830
193
290
556
878
1552
170
264
492
776
1391
155
237
445
703
1259
143
220
410
659
1142
135
202
381
600
1083
126
190
357
571
1010
117
182
337
542
952
105
161
299
483
864
95
146
278
439
776
88
135
249
401
717
82
126
234
375
688
4"
9700
8800
8100
7500
7200
6700
6000
5500
5000
4600
4"
6735
4626
3748
3192
2840
2577
2372
2196
2108
1962
1757
1610
1464
1347
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