Sterling QVEB - Manual (Page 8)

Check all pipe joints for leakage
using a soap solution or other approved
method. Never use an open flame or severe
personal injury or death may occur.
Figure 6 - Pipe Installation, Standard Controls
Never use an open fl ame to detect
gas leaks. Explosive conditions may exist which
would result in personal injury or death.
The appliance and its individual shutoff valve must
be disconnected from the gas supply piping system
during any pressure testing of that system at test
pressures in excess of 1/2 psig (3.5 kPa).
The appliance must be isolated from the gas supply
piping system by closing its individual manual shutoff
valve during any pressure testing of the gas supply
piping system at test pressures equal to or less than
1/2 psig (3.5 kPa).
Table 4 - Gas Piping Requirements*
PIPE INSTALLATION
1. Install the gas piping in accordance with applicable
local codes.
2. Check gas supply pressure. Each unit heater
must be connected to a manifold pressure and
a gas supply capable of supplying its full rated
capacity as specified in Table 4. A field LP tank
regulator must be used to limit the supply pressure
to maximum of 14 inches W.C. (3.5 kPa). All piping
should be sized in accordance with the latest
edition of ANSI Standard Z223.1 National Fuel
Gas Code; in Canada, according to CSA B149.
See Tables 1 and 3 for correct gas supply piping
size. If gas pressure is excessive on natural gas
applications, install a pressure regulating valve in
the line upstream from the main shutoff valve.
3. Adequately support the piping to prevent strain on
the gas manifold and controls.
4. To prevent the mixing of moisture with gas, run the
take-off piping from the top, or side, of the main.
5. Standard gas unit heaters, optional two-stage units,
and hydraulic modulating units are supplied with a
combination valve which includes:
(a) Manual “A” valve (b) Manual “B” valve
(c) Solenoid valve (d) Pilot safety (e) Pressure
regulator
Pipe directly in to combination valve (see Figure 4).
6. A 1/8 inch N.P.T. plugged tapping, accessible for test
gauge connection, must be installed immediately
upstream of the gas supply connection to the
appliance
7. Provide a drip leg in the gas piping near the gas
unit heater. A ground joint union and a manual gas
shutoff valve should be installed ahead of the unit
heater controls to permit servicing. The manual
main shutoff valve must be located external to the
jacket. See Figure 6.
8. Make certain that all connections have been
adequately doped and tightened.
CAUTION: Do not over tighten the inlet gas piping
into the valve. This may cause stresses that would
crack the valve!
NOTICE: Use pipe joint sealant resistant to the
action of liquefied petroleum gases regardless of
gas conducted.
8
Gas Type
Manifold
Pressure
Supply Inlet
Pressure
Natural Gas
3.5 in. W.C.
(0.9 kPa)
14 in. W.C. Max.
(3.5 kPa)
5.0 in W.C. Min.
(1.2 kPa)
Propane (LP) Gas
10.0 in. W.C.
(2.5 kPa)
14 in. W.C. Max.
(3.5 kPa)
11.0 in W.C. Min.
(2.7 kPa)
*For single stage applications only at normal altitudes.
D3631C