Cutting Corners

[eggman08.2008]

I've recently got back into the trade after being offered a job by a friend of a friend. Since then i've been asked to install a sanyo heat pump cassette. I obviously excepted the work to make a bit of extra cash. So i was just reading through the installation instructions for the unit and noticed a few things that my boss does not do.

The things the manual says youm must do that my boss doesn't;

1. Apply refrigerant lubricant to all flares. ( I assume refrigerant lubricant is oil ? )

2. Remove the knock-out hole from the side of the cassette unit and connect to a insulated duct drawing in outside air with a fan motor controlled by a bipolar ON-OFF swich with safety fuses.( my boss simply removes the knock-out hole )

After noticing this I looked through a few more instruction manuals and noticed that when installing a Sanyo multi system you are supposed to replace air inside the copper tubing with Nitrogen gas to prevent copper oxide film forming during the brazing process!

Are these things neccessary or are the manufacturers just going over the top to protect themselves.

Basically, is my boss a cowboy or are cutting these corners acceptable within the trade ?

[Brian_UK]

............

Basically, is my boss a cowboy or are cutting these corners acceptable within the trade ?
I think that you have answered your own question.

Be aware also that you should hold a Refrigerant Safe Handling ticket before working on these things.

[US Iceman]

Are these things necessary or are the manufacturers just going over the top to protect themselves.


Let me answer this in this manner...

Anytime an equipment manufacturer includes a recommendation for the installation to proceed in a specific way you would do well to follow those instructions. These requirements are stipulated by the manufacturer for specific reasons:

1) To enable the equipment to reach it's maximum life span

2) To get the equipment through the warranty period

Not following the manufacturers recommendations are short-sighted and not based on any valid reason from the customer/equipment point of view.

When someone tells you not to follow the manufacturers instructions they are usually:

1) Hoping the equipment breaks soon so they can charge more money

2) don't think the manufacturers know anything; i.e., I know more than they do!

3) just plain stupid...

[eggman08.2008]

I've got my nvq level 2 & a 2078 refrigerant handling certificate, so I am legally qualified. And I have the experience to install small systems.( cowboy style it turns out ). I just wanted to do a good job on my own installation.

Can I ask then, what is refrigerant lubricant and what is a bipolar ON-OFF switch ?

Also how do I fit the switch, is it simple? As I work with cowboys I dont think I've seen one.

And just for training, what about the nitrogen, how do I do this?

[TRASH101]

Can I ask then, what is refrigerant lubricant and what is a bipolar ON-OFF switch ?

Also how do I fit the switch, is it simple? As I work with cowboys I dont think I've seen one.

And just for training, what about the nitrogen, how do I do this?


The refrigerant lubricant is as you guessed the oil.

If you choose to lube the flares then use same type of oil as used in the equipment.(oil will help a bad flare)

The bipolar switch is just another name for double pole isolater.(does the space require fresh air in this manner) Make sure you use the correct knock-out and size your fan carefully.

The OFN is trickled through the pipe/section you are brazing to displace the air not to pressurise in any form so make sure it is opened ended.

Sometimes gas handling courses are not enough and good tuition is hard to get.

There are some good courses out there try contacting POOH hes a good bloke;)

[eggman08.2008]

Where would I get the electrical feed from to power the fan, would I get it from the indoor unit or directly from the mains? And how do I calclaute what size fan I need ?


Oh... and thanks :D

[The Viking]

OFN and lubricated flares=absolutely necessary.

The fan to introduce fresh air is an optional accessory and it's really down to what the customer need/have ordered. But if the fresh air option isn't used then the knock out plate should be left in situ.

If you fit a fan then you have to look in to the rating of the fan motor and decide if the feed can come from the A/C or if it needs a separate supply.

[monkey spanners]

Just to complicate things, depending on the site, the fresh air fan may need to be integrated with the fire alarm system so that its shut off in case of a fire.... Also it would need its own filter as it supplies air to the cassette after the filter in the grill, unless you want a room full of wasps and leaves and such.Jon

[TRASH101]

You must establish the fresh air requirements for the space first accounting for any other natural or mechanical ventilation. All AC can only cope with a specific volume/quality of fresh air. This must be calculated in conjunction with the space load and may require additional heating.

Check manufacturers literature!!!!!!!

Jon has a good point about fire regs and you may need a fire damper and/or other measures to ensure fire compartment integrity.

[eggman08.2008]

Is the Nitrogen neccessary when brazing on all units or just on Multi systems?
Or is it only neccessary when stated by the manufacturer to do so ?

[NoNickName]

Is the Nitrogen neccessary when brazing on all units or just on Multi systems?
Or is it only neccessary when stated by the manufacturer to do so ?

Nitrogen is always necessary when brazing copper to prevent oxidation, unless the torch gas has already a premixed anti-oxidising agent, like gasflux (http://www.gasflux.com/liquid.htm).

[Tycho]

Nitrogen is always necessary when brazing copper to prevent oxidation, unless the torch gas has already a premixed anti-oxidising agent, like gasflux (http://www.gasflux.com/liquid.htm).

seems like that stuff is only for the outside of the pipes to make the brazing look good.

you would still need OFN on the inside of the pipe.


--------------------

Eggman, you should take two small pieces of copper pipe, heat one till it is glowing red and then let it cool down.

then take the other pipe, allow a small tricle of OFN to flow through it as you heat it up till it's glowing red and then let it cool down.

Make sure your boss is watching and get's an eye of the result

[eggman08.2008]

Thanks for the advice every one. It seems like i'l get better training by just asking questions on this site than from working with my boss!
So you probally see a few more questions on this site from me in the future.

[Brian_UK]

Thanks for the advice every one. It seems like i'l get better training by just asking questions on this site than from working with my boss!
So you probally see a few more questions on this site from me in the future.and, we don't charge for the advice.

We do however accept virtual doughnuts (donuts) :D

[marc5180]

If the compressor was to break down after a few months of use (due to oxidisation left in the pipework because you didn't use nitrogen) the manufacturers may ask for the compressor to be sent back for them to examine why it failed. once they cut it open and find out that it failed due to poor installation, they will void your warranty and you will have to pay out.

[NoNickName]

If the compressor was to break down after a few months of use (due to oxidisation left in the pipework because you didn't use nitrogen) the manufacturers may ask for the compressor to be sent back for them to examine why it failed. once they cut it open and find out that it failed due to poor installation, they will void your warranty and you will have to pay out.

That what happens in a perfect world. In the real world, a sales dept. rep. of the compressor manufacturer will put the blame on the guys who engineered the compressor, and will offer a new compressor for free, blaming the engineers that are always trying to let away the customers with a flawful compressor.