safety inspection and tune-up for a residential gas furnace

[ra533yahoo]

I plan to hire a technician to have a safety inspection and tune-up for my residential gas furnace.

Do you -
1. how they charge, for example, separately charge for diagnostic and repair?
2. how can I know the technician is certified to do this job?
3. after finishing, will they give me a document about how to inspect and tune-up?
Thank you very much!

[Freon]

Every company is different. Therefore I suggest you call 3 or 4 and have them send you the procedure (check list) they follow to do the inspection. Also ask for the charge of the inspection. Usually any needed remedial work will be noted and you may be given an estimate depending if the inspection tech is also their estimator.

As to the competency of the tech, you can't know for certain. Asking friends to recommend companies is one way to possibly increase your chances of competence. But the only required license I know of is for working on AC systems where the refrigerant is involved. And how much time a person spends at each inspection point is anyone's guess unless you watch him closely... usually not a good idea.

Again, ask each company what kind of report they provide as they will vary. Your biggest concern is if the tech says there is a crack in the heat exchanger, I would ask him/her to show you this crack. Some jurisdictions require the tech to "red tag" the furnace if it has a cracked heat exchanger or is otherwise deemed unsafe.

[nomadpeo]

one thing techs should be checking for is temperature rise. this differential indicates whether there is an air flow issue that could cause premature deterioration of the furnace heat exchanger as well as possibly detecting a restriction at the surface of the evaporator. air flowing across the furnace to pick up heat and carry it into your house also has to travel through the fins of the evaporator. the acceptable rise is published on the name plate of the furnace.

the older the furnace, the more likely a crack in the heat exchanger. over the last 20 years, there have been great strides in technology improvement. changes in alloys, physical design and electronics have made furnaces more 'failsafe' and less susceptible to cracks and other heat related defects. units manufactured in the last 5 years are safest, but are not designed for excess heat buildup. in most cases, if this problem exists, heat limit sensors strategically located in the unit will detect the problem and after repeated incidents of detection, will lock the system out, which of course will result in failure detected by you when your heat doesn't work.

any system over 10 years of age should be tested for cracks. as mentioned by another contributor, though a necessary safety inspection, the process can be used by unscrupulous people to scam you into buying a new furnace before you need to. the method of checking can include an electronic detector used to determine if there is carbon monoxide in your air stream. units 15 years and older may have a heat exchanger design that requires removing the burners and/or blower assembly to inspect the heat exchanger for cracks.

other inspection items should include testing for gas leaks, running the system through its cycle to test sequence of operation, testing safety controls for proper operation and verifying proper thermostat operation. beware of companies that hire sub-contractors to do service. not all, but some contractors and their sub-contractors make their money through sales and gouging. find out fees up front and as was mentioned, request a complete rundown on checklist items as well as a complete report of findings. you can always get a second and third opinion.

[ra533yahoo]

Thank you nomadpeo and Freon for answering my questions in detail! it is very kind of you, thank you again.