New Installation

L7224A,C; L7248A,C,L

IMPORTANT

Immersion well must fit sensing element and sensor must rest against bottom of well.

OIL ELECTRONIC AQUASTAT® CONTROLLERS

SENSOR WIRES

CONTROLLER CASE

BOILER

Order well assemblies separately; see Table 1 and form no. 68-0040, Immersion Wells and Compression Fittings for Temperature Controllers. Boilers usually have tappings that allow the well to be mounted horizontally so boiler water of average temperature can circulate freely over the well.

1.Turn off all power and drain the boiler, if applicable.

2.If no tapping is provided, prepare properly sized and threaded tapping near the top of the boiler.

3.Sparingly coat the well threads with pipe dope.

NOTE: Do not attempt to tighten by using the case as a handle.

4.Install the well in the boiler tapping and tighten securely.

5.Refill boiler and check for water leakage.

6.Loosen but do not remove the well clamp screw.

7.Fit the case into the well so the clamp on the case slides over the flange on the well.

8.Securely tighten the clamp screw.

9.Insert the sensor element into the well until it bot- toms. See Replacement Sensor Installation section for details. (If necessary, slightly bend the wire inside the case to hold the sensor against the bot- tom of the well.)

10.Turn power ON.

11.Set High Limit, Low Limit and Low Limit Differential to the settings recommended by the boiler OEM. (See OPERATION section.) (See INSTALLATION steps 6 and 7.)

12.On L7248L models, adjust ELL option to match your configuration (see OPERATION section, and Fig. 11 and 13).

IMPORTANT

Best thermal response is obtained with a well that snugly fits the sensor. Insert the sensor until it rests against the bottom of the well. Use a well of correct length and bend the wiring, if neces- sary, to hold the bulb against the bottom of the well.

If the well is not a snug fit on the sensor, use the heat-conductive compound (furnished with TRADELINE® models) as follows: Fold the plastic bag of compound lengthwise and twist it gently. Then snip off end of bag and work the open end of the bag all the way into the well. Slowly pull out the bag while squeezing it firmly to distribute compound evenly in the well. Bend the wiring, if necessary, to hold the sensor against the bottom of the well and to hold outer end of the sensor in firm contact with the side of the well. See Fig. 2. Wipe excess compound from the outer end of the well.

IMMERSION SENSOR

WELL

HEAT-CONDUCTIVE COMPOUND (OPTIONAL)

IMMERSION

WELL CLAMP

M16120

IMMERSION WELL

CLAMP SCREW

Fig. 2. Position of sensor in immersion well.

Flush-Mounted Aquastat

Replacement

Turn off all power and remove the old control. Refer to the cover insert of the old control to identify and tag each external lead as it is disconnected. If the old well is unsuitable for the new installation, remove it and replace it with a suitable new well. If the old well is suitable, use it.

Well-Mounted Aquastat

Replacement

Turn off all power and remove the old control. Refer to the cover insert of the old control to identify and tag each external lead as it is disconnected. If the old well is unsuitable for the new installation, remove it and proceed with instructions for new installation. If the old well is suitable, use it.

1.Loosen, but do not remove, the well clamp screw on the side of the control case.

2.Position immersion well clamp snugly over the flange of the adapter and tighten the clamp screw.

3.Insert the sensor into the well as shown in Fig. 2 or 3. (See Replacement Sensor Installation section for details.)

THERMOSTAT
TERMINALS
DISPLAY								FUSE
	3	2	1
T	T
			LINE
			ZR	L1	L2	C2	B2	C1	B1	ZC
ENVIRACOMTM		SENSOR		SENSOR HOLES						M32186
TERMINALS		CONNECTOR								M32186

Fig. 3. Circuit board, showing sensor connection and

well holes for horizontal mount models.

3	68-0281EFS—05