U2 COMBINATION VIEWING HEAD AND SIGNAL PROCESSORS
3
66-2071—02
APPROVALS
The U2 is a FM approved combustion safeguard and flame
sensing system. The U2 also carries the following approvals.
Table 2. Approvals.
Special conditions of use for IECEx as indicated below.
NOTES: Special Conditions for Safe Use:
1.
Consult the manufacturer if dimensional information on the flameproof joints is necessary.
2.
The aluminum surface of the Honeywell U2 flame monitoring system may store electrostatic charge and
become a source of ignition in applications with a low relative humidity (<30 %) where the aluminum surface
is relatively free of surface contamination such as dirt, dust or oil. Cleaning of the painted surface should
only be done with a damp cloth.
3.
The apparatus has flying lead conductors that exit the enclosure. A suitably certified Ex d or Ex e terminal
box is required to be connected to apparatus enclosure for completing to external supply circuits.
WARNING
“Lockout” requires operator action.
To prevent explosion in hazardous atmospheres, do not open housing.
* Not including aliphatic hydrocarbons (hexane) and acids atmospheres in Class I, Division 1 locations.
** To reduce the risk of ignition of hazardous atmospheres, an approved sealing fitting is required at the
enclosure in Class I, Division 1 locations.
INSTALLATION
Grounding and Shielding
IMPORTANT
Installer must be a trained, experienced flame safe-
guard service technician and should be familiar with
the equipment operation and limitations and be
aware of any applicable local codes and regulations.
1.
Connect a safety ground to the U2 housing (if applicable).
2.
The U2 and all associated cable/conduit must be at
least 12 inches (31 cm) from any source of high energy
or voltage (for example, igniter equipment).
3.
Install a ground wire from the ignition transformer case
to the igniter assembly.
4.
Ensure all igniter wires and cables show no signs of
wear. Replace any igniter cables or wires that are frayed
or cracked.
5.
The U2 must be electrically isolated from the burner
front.
a. Electrical isolation can be accomplished by install-
ing an Ultem locking coupler adapter (R-518-PT12
or R-518-PT12L) in conjunction with a locking cou-
pler (R-518-CL12-HTG or R-518-CL12-PG)
between the viewing head flange and the burner
mount.
b. The purge air line should also be isolated from the
viewing head. This can be accomplished by install-
ing any insulating material, for example a rubber
hose, in between the purge air line and the U2.
Wiring
U2 models with a pipe fitting have slightly different wiring than models with a removable connector. Refer to the table and diagram
below for wire function, connection, and comments. Honeywell C12S cable colors are referenced for the Connector (CAB22) wires.
Market
Pipe fit series (-PF)
Connector series
FM-U.S.
CLASS I, II, III DIV 1 GROUPS A, B, C, D, E, F, & G, T6
*Not for use in acidic or aliphatic hydrocarbon atmospheres.
**Must be sealed at the enclosure.
XP / I / 1 / ABCD / T6 Ta = -40°C to +70°C;
DIP / II, III / 1 / EFG / T6 Ta = -40°C to +70°C;
I / 1/ AEx d IIC / T6 Ta = -40°C to +70°C;
21/ AEx tb IIIC / T85°C Ta = -40°C to +70°C;
CLASS I, II, III DIV 2 GROUPS A, B, C, D, E, F, & G, T5
DIP / II, III / 2 / EFG / T5 Ta = -40°C to +70°C;
NI / I, / 2 / ABCD / T5 Ta = -40°C to +70°C;
I / 2 / AEx nA nC IIC / T5 Ta = -40°C to 70°C; IP66
21/ AEx tb IIIC / T85°C Ta = -40°C to +70°C;
FM-Canada XP / I / 1 / ABCD / T6 Ta = -40°C to +70°C;
DIP / II, III / 1 / EFG / T6 Ta = -40°C to +70°C;
I / 1/ Ex d IIC / T6 Ta = -40°C to +70°C;
DIP / II, III / 2 / EFG / T5 TA = -40°C TO +70°C;
NE / I, / 2 / ABCD / T5 TA = -40°C TO +70°C;
I / 2 / EX NA NC IIC / T5 TA = -40°C TO 70°C; IP66
IEC
IECEx FMG 13.0023X
Ex d IIC T6 Gb IP66
Ex tb IIIC T85C
Temperature range: -40 to +185 ºF (-40 to +70 ºC)
IECEx FMG 13.0023X
Ex nA nC IIC T5 Gc IP66
Ex tb IIIC T85C
Temperature range: -40 to +185 ºF (-40 to +70 ºC)
