Have a look at general maintenance tips below
Boilers Inspection and Maintenance Tips

Ignitor seems to be faulty . have it checked before refiting it.

Dear Sir/madam,

Click this link for more details....


http://www.energymanagertraining.com/equipment_all/boiler/boiler_tips.htm

http://www.masterplumber.net/remove_air.htm

thanks
good luck

How a Central Air Conditioning System Works



Facts:

• The typical central air conditioning system is a split system, with an outdoor air conditioning, or "compressor bearing unit" and an indoor coil, which is usually installed on top of the furnace in the home.
• Using electricity as its power source, the compressor pumps refrigerant through the system to gather heat and moisture from indoors and remove it from the home.
• Heat and moisture are removed from the home when warm air from inside the home is blown over the cooled indoor coil. The heat in the air transfers to the coil, thereby "cooling" the air.
• The heat that has transferred to the coil is then "pumped" to the exterior of the home, while the cooled air is pumped back inside, helping to maintain a comfortable indoor temperature.
• Central air conditioning can also be provided through a package unit or a heat pump.

• Indoor comfort during warm weather - Central air conditioning helps keep your home cool and reduces humidity levels.
• Cleaner air - As your central air conditioning system draws air out of various rooms in the house through return air ducts, the air is pulled through an air filter, which removes airborne particles such as dust and lint. Sophisticated filters may remove microscopic pollutants, as well. The filtered air is then routed to air supply ductwork that carries it back to rooms.
• Quieter operation - Because the compressor bearing unit is located outside the home, the indoor noise level from its operation is much lower than that of a free-standing air conditioning unit.

It just needs a cleaning .. I bet it hasn't been serviced in years since you had a leak.

.. just like a car .. you heating equipment needs regular maintenance.

.. get a certified technician to give it a tune-up.


.. the burner assembly needs to be removed and cleaned .. as does the pilot tubing, flame sensor, and heat exchanger.

You could eliminate the boiler thermostat by temporarily removing the two wires from the rear and connecting them together. The thermostat is in series with the live feed to the gas control valve.

Just because you replaced the thermocouple last month doesn't not mean that this is not faulty, can you measure any output voltage from it? Has the nut loosened?