Utica Boilers UB90-200 Istruzione Sull'Installazione

• Diaphragm type differential pressure switches are 

connected by vinyl tubing to gas valve, air inlet 

connection on negative side, and sight glass adapter 

on positive side. Pressure switches monitor air flow 

by sensing differential pressure measured in inches of 

water (” w.c.). 

• Switch factory settings are 0.5” w.c. on normally open 

switch and 3.5” w.c. for normally closed switch. 

• See pages 31-32, “Detailed Sequence of Operation,” for 

details.

Blower provides means for pushing combustion air into 

and through mixer, burner, and flue ways of cast aluminum 

boiler section before being discharged through vent piping 

to outdoors. 

• Forced hot water system requires at least one circulating 

pump. 

• Circulating pump provides energy to move water 

through closed loop supply, return piping systems, 

terminal heating equipment (finned tube radiators, etc.) 

and back through boiler for reheating. 

• To provide required hot water flow rates, circulator 

pump must be properly sized to overcome frictional 

losses (usually measured in feet of water, also referred 

to as “pump head loss”) of supply and return piping 

systems and boiler. 

• Circulator pump is furnished in a carton within boiler 

cabinet. Locate circulator(s) on downstream (i.e., 

“pumping away”) side of expansion tank.

Manual drain valve is means of draining water in heating 

system, including boiler, hot water supply and return piping 

systems installed above drain valve. 

Install drain valve in ¾” tapping at bottom of boiler. 

Piping installed below drain valve elevation requires 

additional drain valves installed at low points in piping 

systems to drain entire system.  

Burn and scald hazard.  Safety relief valve could       

discharge steam or hot water during operation.       

Install discharge piping per these instructions.

     

• Each boiler must have properly sized and installed 

A.S.M.E. rated pressure relief valve. 

• Water expands as it is heated by the burner/boiler 

sections. If no place for water to expand its volume, 

(i.e., properly sized functioning expansion tank) 

pressure inside of boiler and heating system increases. 

• Pipe pressure relief valve discharge with same size as 

valve discharge opening to open drain, tub or sink, or 

other suitable drainage point. Do not subject to freezing, 

in accordance with A.S.M.E. 

• Failure to provide pressure relief valve with piping as 

described may cause water damage and/or serious 

bodily injury. 

• Boiler equipped with blocked vent safety shutoff, shuts 

off main burner gas in event airflow of combustion 

products through flue-way is reduced. 

• Air will not be available to support combustion if flue-

way is blocked.  IBC locks out due to loss of adequate 

air flow. 

• Pressure switches monitor air flow by sensing differential 

pressure. Contacts normally open and close when draft 

inducer is running causing differential pressure at switch 

to exceed settings. Closed switch proves adequate air 

flow for combustion. 

• Pressure switch shuts off main burner if differential 

pressure is inadequate due to blocked vent pipe, blocked 

air intake, blocked boiler section, or blocked air inducer. 

After 5 minutes of inadequate differential pressure, IBC 

will lock out. 

• “Purge” indicator lamp blinks, see Figure 19, Page 26,

 

indicating failure to prove adequate combustion air 

flow or flue gas flow. IBC automatically resets after 15 

minutes or manually reset as noted see “C” page 26

. 

 

Boiler cannot be restored to normal operating condition 

by resetting control, contact qualified service agency to 

check heat exchanger flue-ways for blockage.

Unit equipped with high limit low water cut off control, 

protects against over temperature and dry firing. Control 

provides burner cut off if unsafe water loss, which can 

result from broken or leaking radiator, pipe, or boiler. Use 

water/glycol mixture 50% with low water cut off. 

Refer to manufacturer provided literature for specific 

features.

Installations where no floor drain or other appropriate 

drainage available, external float activated condensate pump 

with integral sump (not supplied) is required. 

May pipe condensate pump to remote tie in point to 

sanitary sewer system. For this application, boiler must be 

installed so proper pitch of piping to external condensate 

reservoir (sump) can be accomplished. Use wood frame or 

blocks to raise boiler as required for proper installation.

• Furnished relief valve automatically opens at 30 psi 

to relieve strain on boiler and heating system from 

increasing pressure.