Instruction Manual
D200156X012
4194HA, HB, HC Controllers
July 2018
45
2. Tip the relay slightly toward the side of the case to clear output pressure gauge and lift out the relay.
not require an O‐ring.
5. Install and tighten the two screws holding the relay in place.
Figure 5‐4. Relay Features
CLEAN‐OUT WIRE
EXHAUST PORT
(NO O‐RING USED)
O‐RINGS
RELAY MOUNTING
SCREWS
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.