Kiln Compressor Replacement

[YellowHammer]

After years of pumping out wood, and probably being shut off a total of maybe 10 days in that whole time, I've started having a few refrigeration problems with my L53.  Several months ago, my evaporator coil blew out and needed to be replaced.  That hurt$$$.  Then a couple weeks ago, I had a high pressure line fail, and just a week or so ago, I had the compressor itself fail.  After paying more money to my local refrigeration guy for the physical repairs than I want to admit, I decided after this last failure I needed to do most of the hardware replacement job myself, with my HVAC guy to check and charge the system.  I thought I'd show folks some of the inner workings of the kiln, and a few  of the steps I had to do to get it making water again.  I was kind of nervous having to do a full replacement of the compressor, but the project was a learning experience and luckily, was more fun than disaster.  Since all the refrigerant had already leaked out of the system due to the malfunction, I didn't have to worry about any pressure on the lines.  

Here's a few pictures of the process, I was lucky to complete the compressor replacement in pretty short order, and thankfully got it right the first time and the kiln was back into service relatively quickly.

Here is the compressor during removal, and the little switch with the red button is the high pressure safety cutout switch.


   

I silver brazed the new compressor in with no real problems.  I used SilPhos rod, a silver, copper, and phosphorus material that my welding shop guy said was perfect for AC work because it didn't need flux so wouldn't contaminate the system.  I also used a neat product called "Cool Gel" which comes in a spray bottle which I applied to the copper compressor stub tubes to keep the heat from the brazing operation from conducting to the inner working of the compressor.  I also used some wet rags as backup. My biggest worry was that I would overheat something and ruin a component, so I really tried to keep the heat localized.  I had to get the joint hot enough for the silver to run, much hotter than a standard lead solder joint, but not so hot to melt an adjacent part, only a few inches away.  After everything cooled down, I pulled a hard vacuum on the system and did some leak checking, and everything checked out.  No leaks.

After previous discussions with Nyle on using an alternative refrigerant to what they use at the factory, as is very difficult to find in Alabama, they made a point in telling me that my HVAC guy couldn't use the standard pressure gage set or sight glass to tell when the system was fully charged.    

Before long, we started seeing some frost, and checked to make sure it didn't propagate to the evaporator and freeze it up.  Nyle likes to run just enough refrigerant to keep the coils cool, but not so much they freeze up.  20 ounces later (it doesn't take much) my HVAC guy shut the tank valve and watched and waited.  
Here is the system operating correctly with the frost stopping at the bulkhead.


And here is what I was looking for, big drops of condensate dripping into the collection pan, and hallelujah, everything is working again.


 

We buttoned everything up, let things run for awhile and reloaded the kiln with walnut.  Break time was over for the kiln, it was time for it to get back to work and earning its keep. 8)

[WDH]

Wow.  I do not believe that I could tackle that. 

[Cazzhrdwd]

Very interesting YH. I see you keep your unit up high, does that help your drying? Or is that the way they install the 50?

[YellowHammer]

It's got to be high due to the way it's built.  I actually think it hinders drying because there is a stagnant air space under the bottom that causes uneven drying in that local area.  However I've cut an opening and put a screen in the bottom of the kiln so now air can enter front the front and the bottom and it blows out the dead spot. 

[slider]

Good job yh was that R-22 that you used ?

[Glenn1]

Very impressive!!  Did you have to order any new parts from Nyle or did you pick them up from a local supplier?  By the way, when other members L53's go down, do you make house calls? ;D

[WDH]

Good question  :D. 

[YellowHammer]

Very impressive!!  Did you have to order any new parts from Nyle or did you pick them up from a local supplier?  By the way, when other members L53's go down, do you make house calls? ;D

I've done a little of both, depending on the parts and if I have time to figure out where to buy them. 

Sure, I'll make house calls if there is food involved. :D

[Glenn1]

Very impressive!!  Did you have to order any new parts from Nyle or did you pick them up from a local supplier?  By the way, when other members L53's go down, do you make house calls? ;D

I've done a little of both, depending on the parts and if I have time to figure out where to buy them. 

Sure, I'll make house calls if there is food involved. :D

For you and Martha,  we've got filet mignon.   8)

[xlogger]

Found it Robert, thanks for your help. Now to figure it out.

[YellowHammer]

@xlogger 
You can see where I've got the low pressure fill line attached to the low pressure side of the system. The low pressure cutoff is on that line and will prevent the compressor from turning on when the Freon is low.  

The infamous high pressure switch with the red button is on other (right side) of the compressor and the high pressure valve on that line is not used during fills.  

The high and low pressure switches are wired in series and connect to the terminal strip in two places.  If you want to bypass the safeties and just bump the compressor for a second, put a jumper across this terminals.  

Be aware that some units have a time delay when calling for cooling, and also the kiln temperature sensor must be at least 80 degrees for the compressor to come on.  You can bypass that by putting the sensor in front of a halogen light or holding it in your hands until it warms up.  

[scsmith42]

Robert, great write up and nice job (as always).

I must admit that I am slightly more risk adverse than you; I always replace the dryer if I open up a system!   :D

Good advice from your welding guy too; SilPhos is the standard rod that is used around here for HVAC silver brazing.  

I'll have to look into the Cool Gel; first that I've heard of it. Sometimes the wet rags can be a pain.

Knock on wood; after almost 16 years of continuous use I have not had to open up the system in my L200.  I've replaced heating strips and lots of thermistors though; but the actual compressor and coils have been fine.

[xlogger]

I was out of town fishing this weekend with no luck now back to fixing my kiln. I looked on Harbor Freight website and see where I can get all the Gauges, pump, scales and vacuum pump I might need to add freon to my kiln for under $150. I've not had any luck getting H vac people who will come or have freon I need, so might watch utube again and try it myself. Now to figure out buying freon in cans or bigger casters. 

[Al_Smith]

I'm far from an expert at it but I can usually figure it .I had a compressor failure on my Water Furnace geo thermal unit .Had two so called experts look at it and neither wanted to do the job .Rather tight fit and a special made to order Tecumseh compressor  .So I did  the job ,compressor weighed 95 pounds .Had to use some some hill Billy  engineering to rig it . ;)
Space was too tight to use acetylene and silver solder ,fire you know not good .Used a turbo torch with a B bottle ,acid flux and Staybrite  8 solder bearing solder.R 22 runs at lower pressure than 304 etc . Found a new compressor on flea bay at about 1/4 the price of a new one which is special order .
I have the gauges,vacuum pump,scales  ,R22 etc .Borrowed the reclaimer to catch the old freon .Installed all new filters  driers etc .Works good .
I'm one of those bull head old coots .I don't mind paying for a job but don't ever try the wool over my eyes like I'm a moron .

[Al_Smith]

A side note to the above and the type solder I used .When I did the job and in testing the compressor after I evacuated the system and added new freon I had a senior moment .I had the sides off the blower and it was bypassing the air coil and thusly the head pressure went sky high to about double what it should be .Before I could shut it down the high pressure  relief built into the unit lifted .I thought I blew the compressor from my stupidity .It was okay after it equalized .The solder didn't fail so in my opinion  it's  good stuff . 

[K-Guy]

Good job!! @YellowHammer 

By the way Robert we might be hiring..  :D

If you others decide to try it, 2 points:
1) Contact us at Nyle for appropriate refrigerants. The amount required may vary depending on the refrigerant.
2) Use the right type of solder 15% silver, regular water line solder will not hold due to the pressures.

[scsmith42]

I was out of town fishing this weekend with no luck now back to fixing my kiln. I looked on Harbor Freight website and see where I can get all the Gauges, pump, scales and vacuum pump I might need to add freon to my kiln for under $150. I've not had any luck getting H vac people who will come or have freon I need, so might watch utube again and try it myself. Now to figure out buying freon in cans or bigger casters.

As I recall my 2003 vintage L200 uses R22, which requires a license in order to purchase.
Stan - do any of Nyle's kilns use an over the counter type of Freon?

[YellowHammer]

Stan, if I hire in, can I use your company jet?

Scott,
If you look up on the Dupont refrigerant website, R134a is used as a blend ingredient in the refrigerant R22 Nyle uses.  

Here's a link
http://holodko.ru/freon/freon%20cross%20ref.pdf

It is bought over the counter at any auto shop.  

It's what we used.

[K-Guy]

As I recall my 2003 vintage L200 uses R22, which requires a license in order to purchase. Stan - do any of Nyle's kilns use an over the counter type of Freon?

@scsmith42
Never use R-22. We use a R-22 compressor because they hold up better.
We have used or use the following:
R-12, MP-39, R-401A, R-416A, RS-24(L53 only) and R-134A.
R-414b is a direct replacement for R-12 and R-417C for R-416A
If you or your tech are planning to use something else contact us. There a few high temp refrigerants on the market, some techs will automatically want to use whatever is on the truck but it may not work.

Over the counter depends on where you are, it varys from place to place depending on demand.

[K-Guy]

@YellowHammer 
The corporate jet is a paper airplane if you think you'll fit I'll mail it to you ( some assembly required).   :D ;D

[Southside]

YH, you would only be able to survive the temps there for maybe 3 days in August a year - and that is if it was an exceptionally hot and humid year.   :D

[Al_Smith]

This refrigerant dog and pony show has been interesting .Just prior to taking r12 of the market you could get those little cans for next to nothing .R-22 was still cheap until you had to have a licence to buy it .----well at least they say you do  :D   Try as they may ,just like modifying chainsaws the refrigeration police cannot stop you from working on your own stuff .Just don't blab too much because the world is full of goody two shoes types . ;) --just a word take as you wish . 

[scsmith42]

Stan, in the even that I ever need to replace the refrigerant in my 2003 vintage L200, what would you recommend as a replacement?

[YellowHammer]

A 2020 L200.  

[Southside]

Working in the sales department already eh YH?  :D