PB Heat EC Series - Manual (Page 11)

9
F. CONTROLS
1. Water Boiler Controls:
Install the limit / operating control, pressure-
temperature gauge and safety relief valve. See Figure
7.1 (Section 7) for proper location. For installations
subject to UL726, a second operating control that
senses water temperature is also required (not
provided). Use an L4080B or equivalent. Install in
the supply piping near the boiler.
2. Steam Boiler with Float Low Water Cut-Off:
Install pressure limit control, pressure gauge, gauge glass
trim and safety valve. See Figure 3.8, Figure 3.9, and
Figure 7.1 (Section 7). See also control manufacturer's
instruction sheet shipped with the control.
3. Steam boilers with Probe Low Water Cut-Off:
Probe models use a longer gauge glass than float
models. The following components are packed in the
Probe Carton (90759):
·
Hydrolevel CG450 LWCO
·
Gauge glass 22-162-10
·
3/4"x 3" nipple
·
3/4" x 3/4" x 1/4" tee
·
(2) 1/2" couplings
Use these components along with the gauge glass
handles and other components from the Steam Trim
Carton and install fittings and controls per Figure 3.10.
The shorter gauge glass located in the Steam Trim
Carton is not necessary for the probe application.
4. Steam boilers subject to UL726:
For installations subject to UL726, a second
operating control that senses steam pressure is
required (not provided). Use a PA404A or
equivalent. On probe boilers, install the additional
pressure control opposite the standard PA404A using
a cross instead of a tee along with a second brass
siphon (not provided). On float boilers, install the
additional pressure control in the location normally
used for the standard PA404A on steam-probe
boilers (fittings not provided).
5. For complete information on servicing and
adjustment of controls, refer to the attached control
specification sheets.
Pipe the discharge of the safety
valve or relief valve to prevent injury
in the event of pressure relief. Pipe
the discharge to a drain. Provide
piping that is the same size as the
relief valve.
CAUTION
Use only the Hydrolevel CG450 as
a primary probe low water. The
CG450 includes a cycle timer to
sense water level under foaming or
surging conditions. Failure to use
this model could result in a failed
heat exchanger.
CAUTION
PIPING AND CONTROLS
Figure 3.8: Steam Boiler with Float Low
Water Cut-Off
Figure 3.9: Assembling Float Low Water Cut-Off
Figure 3.10: Steam Boiler with Probe Low
Water Cut-Off