Honeywell L91D Manual Do Utilizador

5

60-2152—08

1. Read these instructions carefully. Failure to follow them 

could damage the product or cause a hazardous

condition.

2. Check the ratings given in the instructions and on the 

product to make sure the product is suitable for your 

application.

3. Installer must be a trained, experienced service

technician.

4. After installation is complete, check out product opera-

tion as provided in these instructions.

1. Disconnect power supply before beginning 

installation to prevent electrical shock and 

equipment damage.

2. When using the controller with a compressor, install 

a dampening device (such as a needle valve, 

header, or surge tank) to dampen pulsations that can 

damage the controller or reduce its life.

When used with steam boilers, always mount the controller 

above the water line in the boiler. A steam trap (siphon loop) 

must always be connected between the controller and the 

boiler (Fig. 2) to prevent boiler scale and corrosive vapors from 

attacking the bellows. Before installing controller, be sure the 

siphon loop has enough water in it to fill lower trap.

The controller can be mounted (1) beside the pressure gauge, 

(2) in a fitting on the boiler provided by the manufacturer, or (3) 

at a remote location in case of excessive vibration.

Make all pipe connections in accordance with approved 

standards. Use only a small amount of pipe compound to seal 

the connection joints. Excess pipe compound may clog the 

small hole in the fitting and prevent the controller from 

operating properly.

To avoid leaks and damage to the case, use a parallel jaw 

wrench on the controller fitting. Do not tighten the controller by 

hand by holding onto the case and turning it.

To mount the controller beside a pressure gauge (Fig. 2), 

remove the gauge. In its place, install a steam trap (siphon 

loop) with a tee on top. Using elbows and pipe nipples, mount 

the controller and pressure gauge on the ends of the tee.

If it is not convenient to mount the controller beside the 

pressure gauge, install a steam trap (siphon loop) in the fitting 

provided by the boiler manufacturer. If there is no fitting, mount 

the steam trap at a location recommended by the boiler 

manufacturer. Screw the controller directly to the steam trap, if 

possible.

If there is excessive vibration at the boiler that may adversely 

affect the operation of the controller, mount the controller at a 

remote location. All piping from the boiler must be suitable and 

solidly mounted. The piping must be properly pitched to drain 

all condensation back to the boiler. If this causes the controller 

to be located at an inconvenient height (on large boilers), it 

may be mounted at a lower level if the connecting piping is 

filled with clean water. A steam trap (siphon loop) must be 

mounted between the remote piping and the controller.

PRESSURETOL

4-1/2 (114) TO 

5-1/2 (140)

BOILER

STEAM TRAP

(SIPHON LOOP)

TEE

PRESSURE

GAUGE

L91

PRESSURETROL

CONTROLLER

M23884

2

1

1

2

50024585-001 STEAM TRAP IS A 1/4 IN. BRASS PIPE WITH

1/4 - 18 NPT EXTERNAL TRHEADS ON BOTH ENDS.

FITTING ON BELLOWS HAS 1/4-18 NPT EXTERNAL THREADS 

ON 0 TO 16 OZ/SQ. IN. AND 0 TO 15 PSI  MODELS; INTERNAL 

THREADS ON ALL OTHER MODELS. SOME MODELS ARE 

ALSO AVAILABLE WITH 1/4-19 BSP-TR INTERNAL THREADS; 

SEE TABLE 1.