Replacing The Case And Cover - Emerson Fisher 4194HA Instruction Manual

Instruction Manual
D200156X012
2. Tip the relay slightly toward the side of the case to clear output pressure gauge and lift out the relay.
3. Make sure the replacement relay has three O‐rings as shown in figure 5‐4. The fourth port is for exhaust and does
not require an O‐ring.
4. Install the replacement relay, making sure the tab on the relay lines up with the tab on the frame (figure 5‐4).
5. Install and tighten the two screws holding the relay in place.
Figure 5‐4. Relay Features
CLEAN‐OUT WIRE
RELAY TAB
W5744
6. Perform the appropriate flapper alignment procedure in Section 3 or 4.

Replacing the Case and Cover

CAUTION
The case and cover are an integral unit; trying to separate them will damage the hinge. If the cover needs to be replaced,
replace the case also.
Note
To remove the controller from the case, first perform steps 1 through 7 of the Replacing the Differential Unit procedure. Then
continue on with step 1 below.
1. Perform the procedure required in the Note above to remove the differential pressure unit from the controller.
2. Open the controller case and remove the nine screws (key 38) from the case and cover assembly (key 1). If the
controller has remote set point (suffix letter M), pry the case slightly to remove the frame (key 3). Inspect the
O‐rings and replace as necessary.
3. Install the controller assembly in the replacement case.
4. Slide the controller frame down to assure an O‐ring seal at the pressure connection. Hold the frame in place.
5. Install and tighten the nine mounting screws.
6. Remove the blow‐out plug (key 72) from original case and install it in the replacement case.
EXHAUST PORT
(NO O‐RING USED)
O‐RINGS
RELAY MOUNTING
SCREWS
4194HA, HB, HC Controllers
July 2018
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