PDA

View Full Version : Diy Hvac



v10rick
06-30-2007, 02:47 PM
I'm building an addition and acting as General Contractor.
The County allows the homeowner to apply for permits and perform all of the work.

I have the background and skills to install HVAC equipment and since there are a number of out of state wholesalers willing to perform the calculations and supply the equipment I'm tempted to make this a DIY project.

A licensed tech would bring the system online.

Has anyone on the forum taken this route?

Problems, issues concerns?

Rick

CHH
06-30-2007, 03:32 PM
Has anyone on the forum taken this route?



Yup. The standard rules apply: comply with code (or better) and don't get caught up in "finish the project'itis." In other words, do it right regardless. Be willing to buy the necessary tools. I now own a combustion gas analyzer that I'm willing to sell...:)

v10rick
06-30-2007, 04:21 PM
Yup. The standard rules apply: comply with code (or better) and don't get caught up in "finish the project'itis." In other words, do it right regardless. Be willing to buy the necessary tools. I now own a combustion gas analyzer that I'm willing to sell...:)

Please tell me more.

What brand did you install?

Did you get a bid from a HVAC contractor before deciding on the DIY project?

Amount saved?

My brother-in-law (excellent mechanic but knows nothing about HVAC) intalled his AC system. He purchased the equipment from a local contractor and when the work was completed the contractor checked it and charged the system.

I have experienced the "get er done" syndrome. Fortunately this project is seperated from the existing living space so if it sits there is no harm done.
Rick

jimbo
06-30-2007, 06:18 PM
Sometimes when you buy furnaces and condensing units online, that is more or less "bootleg". The major manufacturers do NOT sell that way. So there is a big question mark about who IF ANYONE will provide warranty parts when needed. One thing for sure, you local contractor, who you are going to screw out of his markup margin on the equipment sale, WILL NOT. If something croaks, either defective out-of-box or later, you will pay him his full service call and labor rate to do that work. So, if you do go this route, factor this information into the equation to see how good a deal it is.

I am curious as to what brand you are looking at. I know for certain that Goodman, Trane, York....DO NOT SELL direct to consumers. They sell only through their authorized distribotor networks, so if someone is selling online, you have to wonder where they got it and what shape it is in.

CHH
07-01-2007, 02:08 AM
Please tell me more.

What brand did you install?

HTP


Did you get a bid from a HVAC contractor before deciding on the DIY project?

I looked at the project several times over a 3 year period and had bids from 3,500 to 10,500. During the bid process one of the high end contractors asked me why I didn't just do the work myself. The same contractor agreed to do the final setup checkout.


Amount saved?

-$5,000 Yup, that's right negative 5K. I "lost" money if I consider my time. I spent about 4 grand on equipment, parts, supplies, and tools. I really didn't do the project to save money. I took it as a challenge and an opportunity to see if I could design and install a system. Some people climb mountains, run marathons, or collect butterflys, I like building mechanical things. The system I installed is in compliance with the manufacturer's requirements and has good access for maintenance. Most importantly, it works!


My brother-in-law (excellent mechanic but knows nothing about HVAC) intalled his AC system. He purchased the equipment from a local contractor and when the work was completed the contractor checked it and charged the system.

Working with the contractor before starting the project should alleviate most of Jimbo's concerns. Find a contractor that understands customer's are not just an ATM and things should go fine.


I have experienced the "get er done" syndrome. Fortunately this project is seperated from the existing living space so if it sits there is no harm done.

Keep in mind that HVAC may not be as simple as it appears on the surface. Your comment about using someone online to do the sizing is a little concerning. I did my own heat load calcs and looked at pressure drops in the piping enough to know that things would work. I'm an engineer so the design aspect was no big deal. I work with natural gas and crude oil systems so I knew I could do things safely and that the resultant installation would be safe. In my opinion, in order to do the job right you've got to educate yourself to at least have a solid basic understanding of the design and application process. HVAC might be "insert tab A into slot B" when putting things together but ya gotta know why and when tab A goes into slot B or you might not understand if it's right and safe.

I probably should have written some form of the following two paragraphs with my first reply:

DIY HVAC is generally not advised. That said, there are many folks that have the training and experience to handle the task. Your brother-in-law doing his own AC is an example of someone who works with tools everyday, has to be safety concious, and had a contractor do the startup. That is a reasonable combination.

On the other hand, if the prospective DIY sells insurance or used cars with a paper cut or spilled coffee as their worst on-the-job hazards and their problem solving skills amount to shuffling paper, well, they better be real careful about taking on a DIY HVAC project. I'm not saying insurance or used car salesmen are bad people. I am using those jobs as examples of positions where one isn't required to be focused on working safely and turning out a product that is safe for other people to use.

Lancaster
07-01-2007, 06:09 PM
What brand is HTP?

v10rick
07-01-2007, 06:14 PM
I am curious as to what brand you are looking at. I know for certain that Goodman, Trane, York....DO NOT SELL direct to consumers. They sell only through their authorized distribotor networks, so if someone is selling online, you have to wonder where they got it and what shape it is in.

Jimbo the authorized distributors will not sell Goodman or others online but they will take phone orders for complete systems.I have located two out of state distributors that sell Goodman and Carrier.

They file the warranty forms and process any warranty claims.

If a local contractor extends the labor warranty beyond the manufacturers then that must be factored into the potential DIY savings.

My objective is to get it done correctly the first time.

In the past 20 years we have purchased 4 new homes (two were custom) and not one of the HVAC systems worked properly.

The HVAC contractors always have the same the same BS story "due to the builders budget limit that was the best system/equipment we could install"

If they were reputable they would not install a compromise system regardless of the builders demands.IMO
Rick

CHH
07-01-2007, 06:24 PM
Heat Transfer Products

Two pictures of the installation:

http://216.98.197.191/MunchZone.jpg
http://216.98.197.191/MunchIndirect.jpg


One picture of what was replaced:

http://216.98.197.191/Triad.jpg

I'll leave the pictures on the server for a couple days.

Lancaster
07-01-2007, 09:25 PM
OK,Heat Transfer Products,thanks,I thought the discussion was about forced air systems.Hydronics would be a different playing field entirely.Maybe I missed it,how did you handle the AC part of the HVAC?

CHH
07-01-2007, 11:43 PM
Forced air or water circulation, they have different problems but they both require some attention to detail. Ever see a sudden thaw and pressure climb to over 400 psi in a commercial freezer system? It'll get yer attention right quick.

For now, it's window and fan for ventilation and cooling in the house. It's worked for 44 years so maybe a few more will be ok.

A contractor has suggested a Unico system and I suspect it's the best way to go. The house only has 100 amp service so that'd have to be upgraded as part of any AC work. Either upgrade the service or convert the stove/oven to gas. The cost is probably a wash. Maybe next year...

v10rick
07-02-2007, 01:38 PM
I learned that BTU calculations are going to be a best guess estimate.

With leaky duct work, enclosed above a finished ceiling, there is no way to determine the loss. In our house 99% of the supply ducts are not visable and tearing down the drywall at this point is not an option.

Complicating matters... the vents in the lower level are closed because it is cool enough without AC. Could it be the leakage is contributing to the the lower level cooling?

The other unknown is the R factor of the roof insulation. This house has foam board above the roof deck, similar to commercial roof installations. The blueprints spec 1 1/2" polyurethane foil faced insulation but since it was installed in 1975 does anyone know the R factor?

When the previous homeowner repaced the cedar shakes he added another layer of 2" R Max R 14.4

The existing 3 ton system cools the house (1100 sq ft above ground) too quickly which does not dehumidify the air so it is oversized.

So much for professional installations.