Heating Help

thanks!

@ July 10, 2011 9:05 PM in 1300 microns!

Great advise! Thanks for sharing!! Going to clean them both tomorrow!!

Tim

simple standards

@ July 10, 2011 3:46 PM in 1300 microns!

Thanks for your reply!

Yes, I swept with compressed nitrogen while braising. I did in fact pressurize with nitrogen, but just to 100 psi to check for leaks. I did not read in any text book about getting up to 425 and I appreciate the advise.  As per Goodman's install manual, I pull down to 250 microns. Is this too far or a waste of time?

When a different system I just did got down to 300 microns, it slowly rose back up to over 1000. I assumed leak, and re-pressurized. No leak. When I pulled down again, it got down to 300 and made an odd noise, and then the microns jumped to 800 with vapor at the pump outlet, then it settled back down. Water boiling out?

At every AC service call, I examine the indoor coil and outdoor coil every time. I pulled a sheet of dog hair off of a indoor coil on a under-performing system last week.

Last week, I had a system that would not pull down normal at all. I went
to lunch (30 min) with the vac pumps running. When I got back, I was
still at 800 microns. When I killed the pumps, the pressure DROPPED to
400 microns and held fine. What happened there? Gauge issue?

Thanks for the discussion. This is my first season offering AC and I am confident I can do this reliably. So far, great results.

Charge!

@ July 8, 2011 11:47 AM in Frozen suction line?

so when I got back the ice had melted. Fired it up. 40 suction and 140 discharge. The factory charge guide is for 15' of line set and I have that much outside. This unit is on the far side of the 3rd floor.

Up to 60 suction now. No ice, air from condenser much warmer.

Frozen suction line?

@ July 8, 2011 9:19 AM in Frozen suction line?

just got a new condenser in and fired up. Came back to check on system and the suction line is frozen on the outside and part of the compressor. Too early to go in the unit to check indoor condition. While I wait for the valve to thaw, what does this indicate? I charged to factory spec with r22 and evacuation held fine.

Thanks.

More cfm

@ July 6, 2011 9:38 PM in 1300 microns!

with a second pump I am down to 350 and falling slow. Yellow hoses larger size to pump. Must just be lots of moisture.

1300 microns!

@ July 6, 2011 8:27 PM in 1300 microns!

I can't seem to draw a system down below 1300 microns. Swapped a condenser on a 3 ton system and can't get a good vacuum. Can't find any leaks either. How long should it take a 5 cfm pump to bring a system with 75' of lines down to 250 microns?

dead

@ June 24, 2011 11:55 PM in Trane chiller issues

Discoloration of the oil. Very high suction pressure. Valve rattle. Compressor shuts down on thermal overload even when run on half-load. No cooling capacity. Blows 150A fuses.

Pronounced dead at about 8:00 PM my time.

Info

@ June 23, 2011 10:29 PM in Trane chiller issues

OK. I won't be able to get the tower recirc pump's pressures because there are no tappings out there. I had it rebuilt last year due to leaking seals.

The hard part will be getting it up & running. Under full load, it is tripping out and will restart if manually reset and the anti-recycle timer times out 5 minutes.

full load

@ June 23, 2011 7:11 PM in Trane chiller issues

Was blowing fuses, 100A. Was kicking off on overloads. Seems to be running much better since I charged with R-22 and fixed the spray nozzles in the tower, but kicked off today, I am back down there tomorrow.

I have 5 gallons of 'condenser / tower de-scaleing additive that I will be adding 1:15 and it claims to de-scale even heavily scaled condensers in hydronic open & closed systems with no down time.

I am also bringing my refrigerant pump to get the rest of the can of R-22 in there if needed.

Any last minute things to check would be appreciated. I have checked the anti-recycle timer and the 2-stage t-stat and other components, and all are working well.

pressures

@ June 21, 2011 8:19 AM in Trane chiller issues

The suction started off at about 65psi but after running for an hour was down at 50. At 90* condenser water, and 42* chilled water temps, I should have 61.1psi. Bubbles in the sight glass. (half empty under full load, just bubbles half unloaded) I brought it back up to 56psi with 15lbs of R-22, full load conditions.

Discharge was 220psi or so, and I should have 204.7 based on the above conditions.

Says liquid capacity of the evap is 27.2 but I think that is the water, not the refrigerant. Does not specify in the manual.

I only considered closing the discharge service valve when cleaning or servicing the filter / drier to be safe but have not done this as I did not know if I needed a complete evacuation prior to servicing the filter / drier. No 'king valve' noticed.

On the tower, I run an anti-scaling solution but not sure if that would do anything for the leigonellia. Tower is fairly new, but has run great so no homework or manual on that part.

Thank you!

Tim

strainer

@ June 20, 2011 10:30 PM in Trane chiller issues

When I fired the unit up 2 weeks ago I cleaned that, but can easily check that again. It pops right out. At start-up, the outlet to the tower is pretty hot, and the water coming back is much cooler. As the chiller takes the building water down, it equalizes pretty fast. The temp to and from the tower were pretty close when I left. excellent pressure at the tower nozzles.

The only strainer I am aware of is in the tower.

scale / condenser

@ June 20, 2011 9:54 PM in Trane chiller issues

So last year I did a de-scale and the solution came out pretty clean. I used a de-scaling solution from Johnstone supply. As for the strainer, is that the large canister in line with the liquid line? I assume I have to recover, fix, evacuate, and recharge to clean the strainer and not just pump down and close the discharge service valve? Should I charge to the correct suction pressure under full load first and see if I get decent results before going through the entire recover / evac / charge process?

The 10-15* delta T is on the cooling tower loop. The building loop is very tight. maybe 5*.

I really appreciate the thoughts on this. It will mean a lot to my customer to have this flying.

Specifics

@ June 20, 2011 7:58 PM in Trane chiller issues

Cooling tower water out is 90*, in was like 75-80*. It did not reach 80* here today. Cooling tower working very well, great flow and new nozzles. Hydro-air system for 45 apartments. Cold generator, water-cooled, condensing, 40 ton. The suction line was 47* and the P/T chart gave me 35* as my calculated temp based on the pressure. There does not seem to be a moisture indicator, just a clear sight glass. I will have to pull up the manual on this chiller and give you the R-22 total capacity. The building water was 43* out (setpoint) and maybe 47* back, (low delta T) but it was not a very hot day. On a chill call, it runs at half-unloaded because there is very little difference in the water temps. The liquid line temp hovered around 80-90* depending on if half of the compressor was unloaded due to being close to setpoint. Filling 15lbs got rid of the bubbles in the sight glass but just started to drop the liquid line temp. I left the superheat set based on the half-unloaded load and jumped the unloader out to stay on half output because of mild conditions and the reluctance to add more refrigerant.

I would love to learn this.  Thanks for the help.

Tim

Trane chiller issues

@ June 20, 2011 4:25 PM in Trane chiller issues

Hello all!

So at the end of last season, I got my refrigeration license and started reading everything I could find. I feel like I am pretty good with residential AC but one of my accounts has a Trane 40 ton chiller with a cooling tower. After going through the entire unit, I found that under full load, it has some issues. The superheat is fine, but the subcooling was way off and there were bubbles in the sight glass. It took 15lbs of R-22 to get the sight glass clear, but the subcooling is still way off and throttling back on the building flow only does so much. I am also still under on the suction pressure but am over with the discharge pressure at full load. The numbers are much better with half of the compressor unloaded.

Am I going to see the subcooling drop out to somewhere close to normal (12-15*) as I approach the correct suction pressure for the condensor water temp and the outgoing water temp I am running? Oil level is fine, pulls right at the max amps under full load. I am a bit worried about having to add over 15lbs of refrigerant to a running system.

Thanks in advance for discussing a newbie topic.

Tim

SF

@ May 31, 2011 9:13 PM in San Fran...

I grew up in the East Bay, but spent a lot of time in the City. Go to Fort Point (under the arch in the Golden Gate Bridge), The Presidio, Golden Gate Park, and the Mission district was cool to see. Pier 39 and Fisherman's Wharf is OK, but very tourist based.

The USS Hornet is in Oakland. Well worth the time!

Tim

Thanks for the reply!

@ May 31, 2011 5:52 PM in Need a core for a Taco HX, coils in shell.

Joe,

Thanks for your reply regarding the replacement core for the Taco HX. Please allow me to provide some honest feedback regarding the prices quoted.

If this HX was going on the space station, a power plant, or a nuclear submarine, I could totally understand the need for such a high level of materials quality control and the price that brings. It is good to know that a company like Taco is capable of producing equipment to these specs. However, this unit is in a 40 apartment complex, and the owner will not pay the amount quoted for the piece of mind that comes with knowing what batch the parts came from and from where these materials were mined....especially when the unit that has failed has a 09/02 date on it. The biggest concern here is balancing cost, quality and down time. If cost becomes the biggest piece of the pie, there is no logical way that this particular unit's cost can be justified when other companies offer replacement components with the same warranty for less than half. To really simplify this, we are discussing a copper tube that makes a single pass in and back, and some baffles and a gasket. The other manufacturers use a single extruded piece, so no braises there either.

I appreciate your reply, but it does appear that I will be installing a Ford HX in a Chevy body to make this repair as cost beneficial and quality minded as possible for my customer.

Tim

Thanks!

@ May 30, 2011 10:42 PM in Need a core for a Taco HX, coils in shell.

That may be just the ticket!!! I refuse to even entertain what my Taco rep wants for a replacement core.

Need a core for a Taco HX, coils in shell.

@ May 30, 2011 9:36 PM in Need a core for a Taco HX, coils in shell.

Can anyone IM me that can find a replacement core for a large Taco HX
for a decent price? I am being taken advantage of by my local rep, I am
afraid.



About 4-5 feet long, 5-6" in diameter. I can get all the exact info Wednesday.





Thanks,  Tim

Need a core for a Taco HX, coils in shell.

@ May 30, 2011 9:35 PM in Need a core for a Taco HX, coils in shell.

Can anyone IM me that can find a replacement core for a large Taco HX for a decent price? I am being taken advantage of by my local rep, I am afraid.

About 4-5 feet long, 5-6" in diameter. I can get all the exact info Wednesday.


Thanks,  Tim

How true

@ April 24, 2011 5:30 PM in It must have been that way for YEARS!!

Sometimes I find the most obvious issues with larger systems and like my original post, just need to take the TIME to follow a pipe, and invest in the proper tools to find the real problem. Troubleshooting is a skill that is quickly disappearing......like steam heat. All it took was chipping away a little plaster to follow a pipe, yet someone changed that pump 3 or more times and could not have given the customer any performance for what they were charged with a closed valve. Just sad....but it makes me look great!

It must have been that way for YEARS!!

@ April 22, 2011 10:30 PM in It must have been that way for YEARS!!

Post your best story that follows the thread title!

Mine is from today. A very old 3-stage B&G, retired and on the floor where it fell. A huge Grundfos bronze circ now hooked up, smoking hot and making funny sound. This is for a DHW recirc loop. That 3-stage must have been changed a few times. So the complaint is no hot water (takes forever) at the kitchen taps, all on one side of the building. I feel the pipes on both sides of the circ and tank side is hot, building side is cold. Remove the circ, no water from building side. Must have a rust clog? Tons of rust, circ is full and all near piping. Must be on track! Still no flow, pipe just disappears into the wall. I chip away at the old plaster that sealed the wall up and find an original (1909) gate valve and weighted check. THE GATE VALVE IS IN THE CLOSED POSITION!! It must have been that way for 20? 30? 40+ years? I can just see the last few guys..."bigger pump, give it a while." "it will heat up in a few hours" Problem is now fixed, happy occupants. Never worked better!

Tim

Boiler mfgs

@ April 22, 2011 9:46 PM in what a great business we are in.....

I had to personally tell the manufacturer of a certain tall, thin, yellow boiler that my install is only as good as their boiler's performance...no matter how well designed and spec'ed my install and parts are. Electrical issues, gas leaks, and so on. There is nothing worse than explaining why this boiler is soo much more than the others, selling it, and having it leave the customer with no heat sporadically throughout the winter. The customer does not want to hear "this is a manufacturer warranty issue"..they just want heat and I feel obligated to make sure they get it. Some manufacturers just don't get it.