Install Instructions
2 Maintenance schedule
8
 WARNING
Have leaks fixed at once by a qualified 
service technician. Failure to comply 
could result in severe personal injury, 
death, or substantial property damage.
Operate relief valve
1.  Before proceeding, verify that the relief valve outlet has 
  been piped to a safe place of discharge, avoiding any 
  possibility of scalding from hot water.
 WARNING
To avoid water damage or scalding due 
to valve operation, a metal discharge 
line must be connected to the relief 
valve outlet and run to a safe place of 
disposal. This discharge line must be 
installed by a qualified heating installer 
or service technician in accordance with 
the instructions in the Combi Boiler 
Installation and Service Manual. The 
discharge line must be terminated so as 
to eliminate possibility of severe burns 
or property damage should the valve 
discharge.
2.  Read the boiler pressure/temperature gauge to make 
  sure the system is pressurized. Lift the relief valve 
  top lever slightly, allowing water to relieve through 
  the valve and discharge piping.
3.  If water flows freely, release the lever and allow the valve 
  to seat. Watch the end of the relief valve discharge pipe 
  to ensure that the valve does not weep after the line has 
  had time to drain. If the valve weeps, lift the seat again to 
  attempt to clean the valve seat. If the valve continues to 
  weep afterwards, contact your qualified service 
  technician to inspect the valve and system.
4.  If water does not flow from the valve when you lift the 
  lever completely, the valve or discharge line may be 
  blocked. Immediately shut down the boiler, following 
  the operating instructions on page 9 of this manual. Call 
  your qualified service technician to inspect the boiler and 
 system. 
Shut boiler down (unless boiler is used 
for Domestic Water)
1.  Follow “To Turn Off Gas to Appliance” on page 9 of this 
 manual.
2.  Do not drain the system unless exposure to freezing 
  temperatures will occur.
3.  Do not drain the system if it is filled with an antifreeze 
 solution.
4.  DO NOT shut down boilers used for domestic water 
  heating, they must operate year-round.
3.  Replace the front access door.
Test low water cutoff (if installed)
1.  If the system is equipped with a low water cutoff, test the 
  low water cutoff periodically during the heating season, 
  following the low water cutoff manufacturer’s 
 instructions.
Reset button (low water cutoff)
1.  Testing the low water cutoff shuts the unit off. Press the 
  RESET button on the low water cutoff to turn the unit 
 back on.
Check boiler piping (gas and water)
1.  Remove the boiler front access door and perform a gas 
  leak inspection per steps 1 through 7 of the Operating 
  Instructions on page 9. If gas odor or leak is detected, 
  immediately shut down the boiler following the 
  procedures on page 9. Call a qualified service 
 technician.
2.  Visually inspect for leaks around water piping.  
  Also inspect the circulators, relief valve, and fittings.  
  Immediately call a qualified service technician to repair 
 any leaks.
 User’s Information Manual
ProLine® XE 
Combi Boiler










