Bill,

am I understanding that the coil was damaged and repaired by the installer with out your knowledge?

Are you having a different company do the repair?

Dewayne, yes, to your first question.  Learning of the situation last week was, needless to say, quite a surprise.  And if it hadn't been for having a WEL monitor, I wouldn't have known I was running the compressor 'into the ground' until refrigerant and/or compressor protection devices would have turned on.

And yes to your second question - it is a different company.  Currently waiting for the company to order / receive the coil, and then schedule the installation.

Best regards,

Bill

Looks to me that a sheet metal screw hit the coil when the return air ductwork was installed. If its the same contractor doing the repair Id insist on a new unit. Coil replacements are not easy not to mention any air or moisture that has already possibly gotten into the system.

I agree with having a different company, but not a new unit. Any and All moisture and air will be removed by PROPERLY evacuating the system before re-introducing refrigerant.

Sorry you are going through this. I hope the repair is not costing you $.

As for the question of repair vs replace I offer the following comments (folks with more tech time than I please comment)

1) That it only needed a 13% charge up and that compressor discharge never exceeded 180 (great data to have) suggests to me that compressor was unharmed by the experience.

2) If repaired properly (including but not limited to: nitrogen purge during brazing, triple evacuation, new dryer, proper charge weighed in) and with good care to avoid additional damage (It looks like you have a roomy, hospitable working area - that helps get quality work). It ought to be OK.

3) An aspect I'm unclear on is oil charge - an undetermined amount was lost, and I don't think recovery and evacuation removes the rest, so I'm unsure how one can be sure the right amount is back in it, unless one can be reasonably assure that the amount lost was small enough so that the remaining amount is within tolerance.

If, however, so much oil was lost that the compressor ran on too low an oil level for awhile, all bets are off.

Again - I'm not an experienced tech so take the foregoing with a grain or two of salt.

Much more damage can be done by to much oil then to little and , there is no way to know how much was lost , likely very little
hate to say it but HACK
accidents happen and there is nothing worse then telling the homeowner or let alone the boss you made a mistake
But to not do so makes you unethical and unprofessional
EPA requires repair of residential leaks with greater then a 10% annual loss , which is just about every leak
considering your loss compressor over heating is unlikely .
Be sure the tech uses nitrogen when brazing
PS if done properly and allowed to cool slowly brazed connection are stronger then the pipe itself
If cooled rapidly ie super soaker or 5 gal pale tossed on it , you are forging the joint and it will be strong but can crack

You will recognize a professional repair by the presence of tools you normally don't see (micron gauge, scale.....). Engineer is close but I would add the proviso that triple evacuation is not mandatory if suitable vacuum is achieved. I believe your units were R-410 which means that when they weigh in (and they better weigh it in) new refrigerant will be added with cylinder upside down to keep the blend together.
If they are replacing the entire fan coil, new joints will likely replace factory joints and your technician is likely as good or better at brazing than the assembler (albeit working with more handicaps such as space limitations etc.). Time frame mentioned sounds about right, most repairs that open the system take a minimum of 3-4, deal with duct work and insulation and 6-8 makes sense.
Wish I could say I never goofed. At least I can say that the customer is always in the loop and proper repairs are made.
Good Luck Bill,
Joe

You are getting good advise about the nitrogen purge WHILE brazing the new component(s) in place as well as pressure testing w/ N2. No soldering for this job.
Also ask if they intend to replace the dryer or ADD a liquid line sight glass and or filter.
The majority of new units do not have a sight glass. Replacement of the OE suction line filter/dryer is not totally necessary if the rest of the system is plugged to minimize air/moisture entrance while dismounting/mounting the evap, but always good insurance.

Super cleaning of the joints to be brazed to include interior degreasing with alcohol swabs will give you the absolute minimum of scale to worry about.

Bottom line is to get in writing that the work methods will not reduce the equipment warranty.

Excellent point on the filter dryer replacement. That would be standard op procedure particularly with R-410, it really sucks up moisture.
If repairman is a WF dealer they will not void manufacturer warranties.
J

The firm that will do the repair is Geothermal Distribution, out of Rockwall (TX).  The company is a WaterFurnace GeoPro Master Dealer (although I don't know what this exactly means other than it's a designation that I don't see on many other WaterFurnace oriented companies in the area).

I've been very satisfied with this firm to date.

Best regards,

Bill

I'm exceptionally appreciative of everyone's counsel.

Looks like the summary is that many believe a coil replacement is a good path to proceed with (versus unit replacement), if, and a key if, the installation is done properly.

And my summary of 'properly,' based on the advice offered, includes:

• Weigh in new refrigerant, with cannister upside down.
• If suitable vacuum can be achieved, triple evacuation is not necessary.
• Pressure test lines with nitrogen after brazing.
• Cool brazed connections slowly to ensure full strength.
• Purge lines with nitrogen while brazing.
• Braze, not solder, the lines.
• Thoroughly clean joints to be brazed, including degreasing interior with alcohol swabs.
• While not absolutely necessary if the lines are properly plugged, installing a suction line filter/dryer is good insurance.
• Use a WaterFurnace dealer for the repair to avoid voiding manufacturer warranties.

Yes, the thinking is a sheet metal screw punctured a line in the coil when the ductwork was being attached to the unit.

Again, many thanks for the super assistance.

Best regards,

Bill

While you have it right, there is some room for variation Bill. If contractor covers 90% of these things, you're doing fine.
J

I teach AdultEd hvac at a local school. I don't claim to be an expert on heat pumps but do teach a course on the basics of them. One of the things I always tell my students is "To be extremely careful about getting any kind of trash into the open system. The control tubes for the reversing valve are very small. Any small metal piece will plug them and cause the valve to quit working." All the other precautions already given are also very good!

ffreeb, many thanks!

Best regards,

Bill

Today was the day for coil replacement.

Items 1 (weigh in R410A), 2 (suitable vaccum achieved at 30 microns, held for 15 minutes), 6 (brazing, not soldering), and 9 (WF dealer) were definitely done.

Item 8 may have been done.  An existing filter/dryer on the discharge, not on the suction line, was resplaced.

Items 3 (pressure test with N2 after brazing), 4 (slowly cool brazed connections), 5 (purge with N2 while brazing), and 7 (clean joints with alcohol) were not done.

Other noteworthy items include:

> Coil was replaced by a genuine WaterFurnace coil, with correct model number for my 3 ton unit.

> Reclaimed R410A was filtered as it went into recovery cannister.

> Later, it was decided to put back in virgin R410A, versus using the recaptured refrigerant.

> I was not charged.

An image of the damaged coil that was replaced is shown below.  Sure looks like a repair to the coil was attempted at the time of unit installation.

The system appears to be working properly at the moment (see http://welserver.com/WEL0043/ ).

Let me know if you have any specific questions.  It was very interesting to watch the job being done.  Took about 6 hours to complete.

I really appreciated everyone's help.

Best regards,

Bill

Hope it continues to work well for many years Bill.
We saw the life span of the previous "artisan's" work.
New guy seems a little more competant.
J

joe

that isnt that bad a thing no different than replacing an a-coil in an a/c. whoever did the job before was not a very good a/c mechanic. that is a patch job with problems from the start too bad but thats what we get sometime. i hope and think the new one will be fine or the manufacture wouldt have allowed for the replacement.

bob

Gentlemen, thanks for the comments.

Yes, after watching the replacement effort, I would agree - same objective as replacing an A-coil in a conventional air conditioning unit.  This job required 6 hours, one person.

The good news was that the return air filter opening was large enough to slip one's head through (see first image at beginning of this thread), and thus get inside to the return air plenum to unscrew the screws holding the old evap coil to the Envision frame.  If instead I had had the OEM WF 2" filters, since I have hard pipe connected to the GSHP unit, it would have required considerable labor to disassemble the duct work.

Otherwise, while the job was time consuming, it was straight forward.  Remove existing refrigerant into reclaim cannister.  Remove lots of armacell insulation, 'Unbraze' the 2 refrigerant lines to the eval coil, and cut out existing filter/dryer from discharge line (new filter/dryer came with new coil).  Mechanically install and fasten down new coil before making any pipe connections.  Braze coil pipe connections.  Braze filter/dryer connections.  Put in reclaimed/new R410A.  Install new Armacell insulation. Start up in Cool mode.  Get unit gracefully to 2nd stage.

Certainly there were many skills that required experience.  Brazing skills to start with, good enough for the high R410A pressures.  Understanding how to 'weigh in' a charge.  Ability to interpret guages and other indicators and understand what they mean.

And plenty of specialized tools.  A purging unit to 'suck out' the old refrigerant.  A vacuum unit to evacuate the system.  Brazing equipment.  Guage set.  Electronic scale with refrgerant connections.  Thermocouple to measure temp.

I certainly strengthened my appreciation for what a professional HVAC tech has to know, understand, and be capable of doing.  Certainly way beyond my ability, knowledge and skill.

I've got a little bit of oil to clean up in the drain pan.

Best regards,

Bill