Service manual

8
The appliance must be installed so that the gas
ignition system components are protected from
water (dripping, spraying, rain, etc.) during
appliance operation and service (circulator
replacement, control replacement, etc.)
Shut off valves must be installed at the inlet and
outlet connections of the appliance to provide for
isolation of the heat exchanger for servicing. If
the appliance is installed above radiation level, it
must be provided with a low water cutoff device
at the time of appliance installation.
This appliance is of a low mass design, which
provides for instant heat transfer. Special
attention to water flow rates will ensure that
temperature rise does not exceed 35°F (19.4°C).
Table 6 is provided as a guide. For application in
areas known to have hard water conditions, or
for soft water contact factory for
recommendations.
Table 6: Flow vs. Head Loss for Various
Temperature Rise
Model
20°F
USGPM
∆P ft.
201
0
170
5.1
2500
200*
8.2
3000
200*
8.2
3500
200*
10.2
4000
200*
10.2
Model
30°F
USGPM
∆P ft.
201
0
113
2.4
2500
1
41
4.3
3000
170
6.2
3500
198
10.2
4000
200*
10.2
Model
35°F
USGPM
∆P ft.
20
1
0
97.0
1.8
2500
121.0
3.3
3000
146.0
4.5
3500
170.0
7.7
4000
194.0
9.8
* Maximum flow recommended. Temperature rise
will be exceeded. CuNi heat exchanger should be
considered for flow rates exceeding maximum
recommended flows.
7.1 PROTECTION DEVICES
PRESSURE RELIEF VALVE (shipped loose)
This appliance is supplied with a relief valve
sized in accordance with ASME Boiler and
Pressure Vessel Code, Section IV (“Heating
Boilers”). The relief valve is to be installed in the
vertical position and mounted in the hot water
outlet. No valve is to be placed between the
relief valve, and the appliance. To prevent water
damage, the discharge from the relief valve shall
be piped to a suitable floor drain for disposal
when relief occurs. No reducing couplings or
other restrictions shall be installed in the
discharge line. The discharge line shall allow
complete drainage of the valve and line. Relief
valves should be manually operated at least
once a year.
CAUTION
Avoid contact with hot discharge water
LOW WATER CUT-OFF (if equipped)
If this boiler is installed above radiation level, a
low water cut-off device must be installed at the
time of boiler installation. Some local codes
require the installation of a low water cut-off on
all systems. Electronic low water cut-offs are
available as a factory supplied option on all
models. Low water cut-offs should be tested
every six (6) months. The normally open switch
contact of the low water cutoff is to be wired in
series with the flow switch. A diagnostic light will
be indicated on the control display on a low flow
condition.
CAUTION
Remove jumper between H & P1 when connecting to
24 VAC circuit.
Figure 3: Low Water Cutoff Electrical
Connections