Utica Boilers UB95M-200 Installationsanweisungen

Differential air pressure switch is a safety device which 

prevents boiler from firing if there is an air intake, boiler 

heat exchanger or vent blockage.
To check differential air pressure:    

Turn off service switch or lower thermostat setting.

Remove vinyl caps from tee.

Install testing lines as shown to inclined manometer 

or differential pressure gauge with ability to read 

0.01” increments to at least 6.0” w.c.

Turn on service switch and set thermostat to call for 

heat.

Not Running

0”

3.5”

Closed

0.14”

Open

Running with 

Blockage

Greater Than or 

Equal To Setpoints

3.5”

Open

0.14”

Closed

Running w/out 

Blockage (approx.)

Min. Fire: 0.3”

3.5”

Closed

Max. Fire: 2” 

0.14”

Closed

If manometer readings do not correspond with chart 

above, check for possible causes:

• Blockage or moisture in suction lines to switch.
• Blockage in air intake or vent pipes.
• Undersized air intake or vent pipes.
• Loose blower wheel on motor shaft.
• Incorrect pressure switch or pressure switch setpoint

When pressure reading is correct and pressure switch 

is operating properly, remove testing lines and reinstall 

vinyl caps to Tee and 3-way connector.

Electric shock hazard! Following procedures may 

expose you to dangerous line voltage. Use caution 

to avoid touching live electrical contacts. All service 

must be performed by a trained, experienced service 

technician. Failure to follow these instructions WILL 

result in death or serious injury

!  

• Do not try to light any appliance.
• Do not touch any electrical switch; do not use 

any phone in your building.

• Immediately call your gas supplier from a 

neighbor’s phone.  Follow gas supplier’s 

instructions. 

• If you cannot reach your gas supplier, call the fire 

department.

  

Fire, Explosion. Shut off gas at a location external 

to appliance should overheating occur or gas 

supply fail to shut off. Do not turn off or disconnect 

electrical supply to pump. Do not use the boiler 

if any part of the gas control system has been 

underwater. 
Only a qualified service technician should inspect 

the boiler and replace any part of control system 

and any gas control which has been underwater.
Use only your hand to turn gas control knob. Never 

use tools. If knob will not turn by hand, don’t try to 

repair it. 
Failure to follow these instructions could result in 

death or serious injury.