Heating Help

Absolutely Recover and Recharge

@ May 17, 2013 6:12 PM in r22 condenser

Since you did not do the original changeout, you cannot be certain that the system was properly evacuated.

If your static pressure is only 30 psig and you are getting extremely high pressures when the system is turned on, it is very likely that there is either air or nitrogen in the system. If the pressure rises immediately, I am leaning towards nitrogen. There is also the possibility that there is a mixture of refrigerants in the system.

In either case, recover the refrigerant (being very careful to not overload the compressor in the recovery unit), pull your 500 micron vacuum and recharge.

I mention being careful with the compressor in the recovery unit simply because, if there are noncondensables in the system, your recovery unit compressor will overheat. Throttle the refrigerant into the recovery unit SLOWLY with the low side valve on your gauge manifold and TAKE YOUR TIME.

Hope this helps.

And Always Will Be!

@ May 17, 2013 1:04 PM in Professor Silberstein is a MAMMA's BOY!

Glad to be one!

Hard to believe, but February 7 marked the 7th anniversary of my mom's passing.

Time marches on, but fond memories live on forever!

A Good Man

@ May 17, 2013 1:02 PM in A hug ,a handshake and some tears.

I'm referring to both of you!

Francisco is indeed a good man, but he is a better man because of, in part, the experiences he had with you.

He was well-trained on all fronts and we all wish him the best with Trane.

I'm hoping your future hires from the college will do us proud as well.

Two Way Street

@ April 26, 2013 6:17 PM in OH NO! OH YES!

I think they are both very lucky!

Big Difference!

@ April 22, 2013 3:18 PM in Window AC water slinger vs dry question

The slinger ring on the condenser fan blade performs two major functions. One is to help evaporate the condensate and the other, a byproduct of the first, is to increase the efficiency of the unit.

Let's assume that our window unit is operating at "design conditions" and that we have an outdoor ambient temperature of 95 degrees (humidity is irrelevant here) and the indoor conditions are 75 degrees at 50% relative humidity.

Since our air conditioner serves two major functions (to dehumidify and cool), the latent heat removed from the system forms our condensate. The temperature of this condensate is about 50 degrees. The condensate is then directed to the back of the unit, where the slinger ring picks up the water and sprays it over the condenser coil.

By doing this, we accomplish a couple of things. First, the cool condensate water absorbs heat from the condenser coil. Second, the spraying water helps cool down the air moving through the coil. Third, as the condensate evaporates, it absorbs even more heat from the condenser coil.

So, to sum things up.... The slinger ring is there for a reason and there is absolutely no reason to drill a hole in the bottom of the unit to prevent it from doing what it is supposed to do.

Hope this helps.

Back to Basics

@ April 19, 2013 7:28 PM in Calling Eugene

I have three things to say in response to your post, David. (1) We need to properly train our technicians. (2) We need to properly train our technicians. And, most importantly (3) We need to properly train our technicians.

In our industry, many of our service personnel were trained in the trenches by others, who themselves, learned the industry from others in the field, and so on and so on and so on.

The business of HVAC/R is changing at an alarming rate and we all need to keep up with the changes. This is not always easy to do.

I can only hope that our technicians are getting educated and reading the directions when encountering unfamiliar or new equipment. Guessing is not an option.

A very wise friend of mine gave me this little anecdote. A field technician encountered an unfamiliar system and need to replace a part on it, The new part came with installation instructions but, since the customer was standing over the technician, he opted to install the part, incorrectly, without referring to the paperwork. Pride and ego often get in the way of doing things the right way. There is absolutely nothing wrong with "reading the book". If a customer chimes in with a statement such as, "You need to look at the instructions?", the technician can easily respond by saying, "Would you rather I put the part in without reading them?". Another response could easily be, "The manufacturers are constantly updating their products and I want to make certain that I am following their recommendations to a tee".

Since I train a lot of field technicians that have a number of years in the field, I have also encountered another interesting scenario. Some technicians are very reluctant to admit what they don't know. This can be a result of ego, but can also be a very different situation. Imagine a technician approaches his supervisor and asks about the operation of a thermostatic expansion valve. The response to the technician can make all the difference in the world. Here are a couple of possibilities:

(1) Glad you asked John. The TXV is responsible for maintaining a constant evaporator superheat in the evaporator coil. The valve is controlled by three pressures; the bulb pressure, the spring pressure and the evaporator pressure. The thermal bulb...

(2) What?! I'm paying you X-amount of money and you don't know that? Maybe I'm paying you too much!

In my opinion, I would rather have a technician that is forthcoming, to the best of his/her ability, in identifying areas of uncertainty so that the technician can learn and become a better tech. This benefits both the technician and the company.

For the most part, I have encountered technicians who are eager to learn and very enthusiastic about the trade. Although there are some who are not as experienced as we would like, I would like to think that the majority of those in our industry are getting trained, doing the right thing, and helping to show our industry in the best light.

No Problem!

@ February 26, 2013 5:34 PM in Prof Silberstein's Birthday ?

My pleasure!

I Could Never...

@ February 26, 2013 6:17 AM in Prof Silberstein's Birthday ?

I could never forget you!

Schedule is a little hectic..... Working on two new books, working on a thesis project, writing a new course on sustainable and renewable energy for the college, getting ready for ISH, getting ready for the HVAC ( er.... I mean HVAC/R - fpr Terry!) Educators conference in Las Vegas...

The next two months are going to be a wild ride.

But I'm still smiling!

Thanks Dan!

@ February 23, 2013 1:58 PM in Prof Silberstein's Birthday ?

Thanks buddy!

See you at ISH.

Possibly a Set-up Issue

@ February 23, 2013 1:58 PM in Help ! Geo is not working correctly.

Not having the literature on the unit in front of me, I can only assume that there is an issue with the set-up/start-up of the equipment.

These systems are equipped with ECM motors that modulate the rate of airflow to the conditioned space based on the needs of each zone. In addition, the compressor is likely a two-stage pump that can adjust its capacity based on the needs of the structure.

Since your system has experienced abnormal compressor and blower activity, the first place to start is have your installer come in and make certain the controls have been properly set, wired and configured for proper operation.

Any one improperly set DIP switch or improperly wired sensor can easily throw the system out of whack.

Please keep us posted.

Freezing Suction LIne

@ February 22, 2013 10:19 AM in Rheem High Pressure Trips

If the suction line (the line that is connecting the evaporator coil to the compressor) is/was freezing, it is highly unlikely (even next to impossible) that the frost is caused by an undercharge of refrigerant.

If a system is undercharged, there will be less liquid refrigerant entering the evaporator coil, causing it to boil off in the coil further away from the outlet of the coil. This will cause the refrigerant, now in the vapor state, to heat up. This makes the suction line warm and will not allow frost/ice to form.

The icing of the indoor coil in the cooling season and the high pressures in the indoor coil in the winter, once again, indicate a problem with the airflow through the structure.

If you would like to discuss, feel free to contact me at (917) 428-0044.

Cheers!

Very Likely an Indoor Airflow Problem

@ February 22, 2013 8:18 AM in Rheem High Pressure Trips

When an evaporator coil freezes, in this case the indoor coil of your heat pump, there are typically two ice patterns present. One is a partially frozen coil, where only the first few tubes freeze and the rest of the coil is warm. The other is when the entire coil freezes.

In the first case, there is either an underfeeding metering device or a refrigerant undercharge.

In the second case, which usually is accompanied by a frozen suction line, is almost always an airflow problem through the indoor coil.

Given that you had a frozen indoor coil in the summer, resulting in low operating temperatures and pressures, and high operating pressures in the heating months, it seems more than likely you have insufficient airflow through the indoor coil.

Be sure to check the filters, as mentioned, as well as the blower wheel itself to be sure it is clean and that the hub on the wheel is not loose. You can also check for closed supply registers or even, possibly, duct lining that might have come loose and is blocking the ductwork. In other words, you need to check all the components of the indoor air distribution system.

Please keep us posted.

I am so sorry Mike

@ February 22, 2013 8:02 AM in Prof Silberstein's Birthday ?

I am so sorry that I did not acknowledge your birthday wish. I actually thought that I did, but it must the "close to fifty thing" setting in.

Please accept my apologies.

Excellent!

@ February 18, 2013 9:42 AM in how much BTU does a person give off

Then the chart provided by SWEI will work perfectly!

Enjoy!

Damaged refrigerant

@ February 17, 2013 11:27 AM in Compressor Burn out

The refrigerant does get damaged, as the hydrofluoric and hydrofluoric acids are formed, in part, by the fluorine and the chlorine in R-22.

Happy Presidents Day.... a little early

For Down-and-Dirty Calculations

@ February 17, 2013 11:25 AM in how much BTU does a person give off

For back-of-the-napkin calculations and for casual conversation, we often equate the heat generated by a person to be the equivalent of a 100-watt light bulb.

Thanks Terry!

@ February 11, 2013 9:45 AM in Prof Silberstein's Birthday ?

Thank you, sir.

Wow!

@ February 11, 2013 9:15 AM in Prof Silberstein's Birthday ?

You are officially an antique!

Yes Ken

@ February 11, 2013 7:49 AM in Prof Silberstein's Birthday ?

Yes indeed Ken!

I hit 47 on the 10th of February....

Thanks for your wishes!

I hope to see you soon!

Very likely

@ February 7, 2013 7:49 AM in electric duct heater

You are indeed correct.
I have seen them installed as a quick fix for problems such as those you mentioned.

Yes... Truly Amazing

@ February 7, 2013 7:47 AM in Costa Rica Research

Yes Mike,
The trip was a life-changing experience!

Agree on Disagreement?

@ February 7, 2013 7:46 AM in bubbles in sight glass

If an air conditioning or refrigeration system is operating close to its intended target temperature, there should be no bubbles in the sight glass. In other words, if the load on the system is relatively low.
However, if the system is operating under high load, such as in the case of a hot pull down on a refrigeration system or an air conditioning system that is turned on when the indoor ambient is high, bubbles will very likely be present in the sight glass. This is due to the metering device (namely the TXV) opening wide to lower the increased evaporator superheat caused by the high load conditions. This increases the flow rate in the liquid line and can result in some flashing.
An old school of though was to charge systems to a full sight glass all the time. In the case of a hot pull down, charging to a full sight glass will result in a system overcharge. This overcharge often goes undetected since TXV systems typically have receivers that store this excess charge.
So, if your system is operating with bubbles in the sight glass and there is a large load on the system, no worries. However, if the system is operating with low load, then you should not see any bubbles in the sight glass.

Hope this helps.