How to Inspect HVAC Systems Course

Tom, I spent a long time in the U.K. too. The things to watch for that is VERY different here, and might pose a health hazard to you is the Electricity!

The electricity itself is still the same, it’ll still kill you, but it’s delivered VERY differently. 240 Volts is delivered via 2 120v hot wires. The Neutral here is really ground (the differential between the 120V and zero), but there’s an extra ground too which is like the U.K.s Earth. (If you’ve worked on electrical systems you’ll get what I mean as you study the courses). There is no such thing (as far as I’ve seen) as a ring circuit, it’s all spurs. ELCBs (or RCBO now) are GFCIs. and Black is HOT unlike the old circuits in the UK where Black was Neutral. If you manage not to get those wrong I’ll talk to you again soon.

Great course. I am a licensed air conditioning/heating contractor for over 30 years in Texas and began home inspections approximately 20 years ago. I do very little air conditionng work and primarily home inspections for a living. This course was a required course but I learned things I had forgotten or never knew. Keep up the good work

Jim:D

I am looking forward to increasing my knowledge of HVAC systems.

Great Course;

This is my second time taking it… As with all the courses offered here, the more you learn, the more you realize how much you need to learn as we are just scratching the surface of the subject matters.

And if you have further education on the subject, you realize how how much this course has been modified to make the course content easier for all members to comprehend the basics of each system.

Regards
Barry Sullivan

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Just starting this course.

We are lucky to have this source for information.
Thanks to all involved.

Been doing HVAC for 14 years. Always look forward to opportunities of testing my knowledge and increasing my knowledge as well.

Looking forward to the course.

Remember, many of InterNACHI’s online courses (including this HVAC course) are also available in soft-cover textbook and downloadable textbooks at our online store -

Printed textbooks:

Downloads:

Starting the course today…I am confident that it will be a great course as all the others have been thus far.

Just starting course. I also started the Nachi TV course. So far, it seems very educational

Hello there! Just beginning the HVAC course for the first time. Thank youfor such great courses

Dale Tolly

done

More info from the 2009 IRC on gas appliance connectors:

Limited to 6’ in length.

Shutoff valve is required upstream of the connector.

Cannot pass through the *cabinet *of an appliance (furnace) even if protected by a bushing.

Cannot be joined to another connecter (only 1 connector for each appliance).

Appliance connectors are CSST and require bonding per G2411.1 (NEC 310.1)

“Most jurisdictions do not permit flexible gas pipes going through walls, floors or ceilings. They cannot be concealed. They are limited in length. And the shut-off valve cannot be in a different room than the appliance unless it is clearly labeled.”

None of the above is a limitation on CSST per the IRC, the IFGC or by CSST manufacturers.

Course language: **“Galvanized Steel
**Black steel is commonly used inside a residential property to carry the natural gas. Galvanized steel is not used [emphasis added] because the zinc coating might flake and clog the line or the appliance. Try not to get confused easily by the appearance of the pipes. A gas pipe may appear to be a water supply pipe, and vice versa. If copper is permitted, both the water and the gas piping may be copper. Special identification of the lines in your jurisdiction may be required or recommended.”

Statement above is incorrect in jurisdictions that go by the IRC

“2009 IRC G2414.4.2 (403.4.2) Steel. Steel and wrought-iron pipe shall
be at least of standard weight (Schedule 40) and shall comply with one of the following:1. ASME B 36.10, 10M;
2. ASTM A 53/A 53M; or
3. ASTM A 106.
Code Commentary: Steel pipe must be Schedule 40 or heavier, must comply with one of the listed standards and can be black iron or galvanized. Contrary to popular belief, natural gas does not adversely react with the zinc coating on galvanized pipe.

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"Drip Leg The drip leg (or dirt leg) should be installed at the heating system. Look for the drip leg at the bottom of the vertical pipe that leads to the gas heating system. The debris that floats in the gas will drop into the drip or dirt leg before entering the vulnerable components of the heating system, such as the gas valve."

Better term in most cases is “sediment trap”. A shut-off valve should be installed *upstream *of the sediment trap so that it can be removed and cleaned during system maintenance.

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Course quote: “All Air from Outdoors If all combustion air is taken from the outdoor air, then one opening should be within 12 inches of the top and one within 12 inches of the bottom of the space. The openings are permitted to connect to spaces directly communicating with the outdoor air, such as a ventilated crawlspace or ventilated attic space. Each opening should have a free area of at least 1 square inch per 4,000 BTU/per hour (550 mm2/kW) of total input rating of all appliances in the space when using vertical ducts (2,000 BTU/per hour if using horizontal ducts).”

2009 IRC G2407.6.2 (304.6.2) One-permanent-opening method.
One permanent opening, commencing within 12 inches (305 mm)
of the top of the enclosure, shall be provided. The appliance
shall have clearances of at least 1 inch (25 mm) from the sides
and back and 6 inches (152 mm) from the front of the appliance.
The opening shall directly communicate with the outdoors
or through a vertical or horizontal duct to the outdoors, or
spaces that freely communicate with the outdoors (see Figure
G2407.6.2) and shall have a minimum free area of 1 square
inch per 3,000 Btu/h (734 mm2/kW) of the total input rating of
all appliances located in the enclosure and not less than the sum
of the areas of all vent connectors in the space.

Code Commentary: Research has shown that for modern appliances, a
single opening to the outdoors will perform as well as
the traditional two-opening method
. The one-opening
method described in this section depends on a reduced
pressure being created in the enclosure by the
draft created by the venting system. This reduced
pressure causes combustion air to enter the enclosure
through the single opening. The opening must be
properly sized considering both sizing criteria: the
square-inch-area-per-Btu/h ratio and the area minimum
based on the sum of the areas of all vent connectors
in the enclosure. This method allows for fewer
openings, fewer ducts and fewer objections by the
owners/occupants.

Boy howdy! Lookin forward to gettin down and doin it, yea! Here I go!
All of the courses proir to this one have been informative and challenging so far! THX Paul Bernier Soledad,Ca

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Taking the course now as well, havent had any problems with the slides loading.