Welcome to Energy Conservation toward reducing your heating & air conditioning costs
Welcome to Energy Conservation toward reducing your heating & air conditioning costs & to ask all kinds of questions.
Feel free to post about anything related to HVAC and/or Energy Conservation.
There are many areas where your air conditioner or heat pump may be losing efficiency, together we can achieve optimal efficiency of operation.
This is valuable free information being offered to you so you can save on your energy usage costs, & practice Energy Conservation for America. Visit my many Energy Saving HVAC web pages at:
http://www.udarrell.com/airconditioning-sizing.html
For Techs a Trouble Shooting chart, for HVAC Techs & HVAC User’s a Service Data Chart to check BTUH Performance:
http://www.udarrell.com/ac-trouble-shooting-chart.html
I am here to help you Conserve Energy & save a lot on your monthly utility bills.
A high percentage of HVAC systems ar operating way under their Rated Efficiency!
Practice Energy Conservation it Pays Big Dividends forn you & for your country.
Visit the HVAC links at the bottom of the pages.
Darrell Udelhoven - udarrell.com
August 16th, 2008 at 10:23 am
Many of today’s larger homes have 2 HVAC units, with often one being smaller. I would think a very efficient 3 stage setup could improve efficiency by using first the smaller unit for the whole house, then when cooling/heating is insufficient, go to the larger unit, then if needed to both units together. I don’t see any discussion or controls offered for this.
August 17th, 2008 at 12:01 am
Hi Mr. Breckenfeld,
Your idea is intriguing!
These are just my opinions!
The duct system would have to be zoned.
I believe it would be doable.
A two story home using one A/C for both floor zones usually has difficulty maintaining optimum comfort from the first floor to the second floor. Warm air
rises to the upper floor & will usually be warmer unless the system is zoned.
You would need a variable speed blower.
An ideal setup might be a Maytag 23-SEER variable speed capacity inverter compressor that would operate as the first stage for both floor areas.
I am not fully informed as to which SEER levels Maytag has the iQ Drive inverter systems, that technology could be the wave of the future.
The duct system & zoning would be a bit costly.
I would just go with a Maytag type setup for the first stage & only kick the other unit on if the heat-gain became too high too handle the load.
Both unit stages would need a VAV (Variable Air Volume) zoning system to keep all the areas properly conditioned.
Other Techs are welcome to comment. - Darrell
September 9th, 2008 at 1:32 pm
what is standard tempature differance from the evaporator to the box temp. is there a special rule of thumb, this is on a walk in freezer
October 25th, 2008 at 1:35 pm
New Three Ton Payne Condenser
August 10th, 2008
I Installed a NEW 3 ton Payne Condenser with driers. Charged the system.
Low side line is sweating good, high side line luke warm. Temp coming out of vents are 69 degrees.
I removed the intire inside system outside and cleaned the coils with evap cleaner. cleaned Blower Motor and Squirrel cage. Replaced it. Evacuated the system and re-charged system.
ow side would not rise above 70 lbs pressure, but high side continued to climb to 350 lbs pressure still not cooling suffeicently. Check ducting for leaks, all looks good. Do you have any Idea what it could be. Rodger Touchette
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I have been purposely waiting so other techs would respond to these questions; they didn’t.
It appears you did not install a new evaporator coil that matches the new SEER & EER of the condenser; Mismatched systems do not work.
What refrigerant does the new unit call for, & is the evaporator & its refrigerant control rated for the same refrigerant? The problem may be at the refrigerant control.
If it is R22 the coil temp would be around 41ºF, if R410A it is only 15ºF; on the high-side 350ºF is 108ºF using R410A, or around 142ºF if R-22. With either refrigerant the high-side is way out of line with the low-side!
It appears there could be a restriction somewhere in the high-side of the refrigerant system.
Make sure the indoor blower is moving close to the correct 1200-CFM for a 3-Ton unit.
Check the condenser discharge air temperature compared to the outdoor temperature & the SEER Rating of your unit.
I am very sorry, I should have responded while the weather was warm.
You should have filled out the trouble shooting data in my other post!
- Darrell
January 29th, 2009 at 5:39 pm
Hi Darrell
I have a few questions. I was a plumber so i do know a few things about the hvac industry. I dont have a ductalator , is there a spread sheet online that gives the cfm per outlet in a home? I have the round piping information, I just need the retangle info. Also is there an easy way to figure fpm.
Heres what i am up against, I need an easy way to figure out if my return is the right size. I have a small home. Six - 6″ outlets. The cfm for the furnace in cooling is 1200. How do i figure out if my return is the right size? Or what size return i need?
February 10th, 2009 at 11:57 pm
Finally someone who knows what they are talking about! Many bloggers just write without having a clue on the topic!
February 11th, 2009 at 7:06 pm
I found your blog on google and read a few of your other posts. I just added you to my Google News Reader. Keep up the good work. Look forward to reading more from you in the future.
March 25th, 2009 at 6:30 pm
Tony, sorry but I have been absent from my log.
The answers to your question & how to figure duct sizing & return air ducts, Grilles & filter racks is all on this web page.
Use the charts & click on the page anchor links for specific areas of the page.
If you need further specific help post a specific question.
http://www.udarrell.com/proper_cfm_btuh_duct_sizing_air_conditioning_systems.html
- udarrell
March 25th, 2009 at 6:49 pm
Ed Hardy & SEO, Thank You for your comments.
Practice energy conservation and learn all you can about HVAC.
http://www.udarrell.com/proper_cfm_btuh_duct_sizing_air_conditioning_systems.html
- udarrell
April 4th, 2009 at 10:11 pm
Latent heat removal.
If you are planning on lowering the CFM across the evaporator to remove additional humidity, should you first charge the system with the nominal air flow suggested by the manufacturer ie. 1000CFM with 2.5Tons or lower the speed first ie. 850CFM and then charge.
Respectfully yours,
April 4th, 2009 at 11:16 pm
Question: Lowering CFM for increased latent heat removal, at which CFM to set the charge.
It depends on whether you are going to use the lower 850-CFM setting all the time.
If the lower setting, then charge it to that 850-CFM & at a little above the normal load conditions it will usually be operating at.
The higher the indoor humidity the higher the load through the evaporator.
Use both Superheat & subcooling to check for appropriate operation of a TXV metering device.
Use just Superheat for a fixed piston device.
Use the diagnostics in all of my Web pages:
http://www.udarrell.com/ac-trouble-shooting-superheat-subcooling.html
- udarrell
April 6th, 2009 at 6:53 pm
I wanted to comment and thank the author, good stuff
May 28th, 2009 at 7:32 pm
I read on your website that you recommend oversizing the coils to increase system efficiency. How much can you oversize them? Will a 2 ton condenser work well with coils designed for 3 tons? Also, what is the smallest condenser unit that you would recommend pairing with 5 ton coils?