so i was doing a tune up on a slant fin boiler 23 years old. on start up, it backfired to the black manifold. it didnt set the rollout off. customer says been happenng for about a year now. just wanted some suggestions on what can cause that. thanks
I would be checking the underside of the heat exchanger. It could be dirty. What was the manifold pressure? Maybe the gas valve is bad and opening to fast. I would also inspect the venting or chimney. Some of those old liners were surrounded by vermiculite that can corrode the liner. Once that happens the vermiculite will fall inside and block the liner.
Did you know if Clause 7.1.12.1 applies to your boiler? This was a new clause incorporating Director's Order FS-156-09 into the Ontario B149.1-15 code.
Quote7.1.12 Mandatory Safety Checks for Residential (one or two family Dwelling) Natural Draft Boilers Equipped with Draft Hoods 300,000 Btuh or less.
Clause 7.1.12.1 - During each heating season effective October 15th to April 30th when a certified G1, G2, G3 or GUT gas technician enters a residential building intended for one or two single families to carry out service, maintenance and/or emergency response work within the scope of his/her certificate, the gas technician shall:
1. Determine if a natural draft boiler equipped with a draft control device and with an input less than 300,000 Btuh is installed in the building. Where such a boiler is installed, the gas technician shall take the following steps unless a valid boiler inspection label as identified in paragraphs (e) and (f) is affixed to the boiler.
(a) The gas technician shall provide the homeowner/user with the Owner/User Information Sheet (Annex "M" Schedule A) that outlines the technician's requirement to inspect and take corrective action where necessary and the homeowner's responsibility to properly maintain their fuel burning equipment.
(b) The gas technician shall take a CO reading in the flue gas upstream of the draft control device (between the heat exchanger and the draft hood) with the boiler operating at steady state under normal operating conditions.
• If the CO reading exceeds 100 PPM, the boiler shall be considered an immediate hazard and the gas technician shall take immediate corrective action to address areas of concern including, but not limited to cleaning of the boiler flue passages and cleaning the burner. If the boiler operation cannot be corrected so that the reading is below 100 PPM, immediately shut off the fuel supply to the boiler, provide notice to the user and distributor and affix a notice to the boiler as outlined in subsection 13(2) and (3) of ONTARIO REGULATION 212/01 (Gaseous Fuels).
(c) The gas technician shall visually inspect the boiler for safe operation. If there are signs of spillage (such as discoloration on the burner door or near the draft control device, or excessive moisture in the boiler room), a depressurization test as outlined in Annex "M" Schedule C shall be performed.
• If the test demonstrates that there is a depressurization issue, then take appropriate action such as adding adequate combustion and make-up air.
• If there are signs of condensation due to excessively low return water temperatures, take appropriate action such as installing a water bypass piping system in accordance with manufacturer's requirements or recommendations.
(d) A carbon monoxide alarm certified to CAN/CSA-6.19-01 shall be installed in accordance with the carbon monoxide alarm's installation instructions and located in the sleeping area or adjacent to each sleeping area in every suite of the home.
(e) If the boiler operation is satisfactory and found with a CO reading below 100 PPM, and the CO alarm(s) are installed, a boiler inspection tag (Annex "M" Schedule "B") shall be affixed to the boiler.
(f) The boiler inspection tag affixed to the boiler shall expire on May 1st following the completion of this requirement.
(g) In the event that boiler is tested between May 1st and October 14th (the off season) of a given year, it is considered a valid test for the period between October 15 of the given year and April 30th of the following year.