- posted on February 19, 2009, 3:37 pm

Look at the Hi/Lo pressures for outdoor ambient.

2 ton - 212/61 @ 40 deg ?

Compare to 1 1/2 ton - 318/96 and 3 ton - 297/86.

- posted on February 19, 2009, 9:56 pm

It should be at 308/90 HI/Low

But I might be wrong also

Just check data for 14 seer here

http://www.goodmanmfg.com/Portals/0/pdf/ss-SSz14.pdf

- posted on February 19, 2009, 11:50 pm

On Thu, 19 Feb 2009 13:56:03 -0800 (PST), HateThatHeatPump

Thanks for input.

My HVAC tech says it should be about 350/100 or so for my heat pump. He has stated to throw out Goodman sheets. I'm awaiting his return right now to troubleshoot problem. He thinks unit was factory overcharge as only 6 oz was added for additional line length.

Here's the response from Alpine when I questioned the strange specs in three emails:

"The manufacturer's spec sheet is based of of ARI industry testing and should be correct. You have to note that your pressures will vary depending on your outdoor and indoor humidity along with the amount of air flow and the and charge the system has. These specs indicate what the correct pressures should be based on the delta T (or temperature drop across the evaporator coil) and the outdoor temperature. If your pressure seem off based on the outdoor temp, I would first look at delta T to see if it's correct."

and

"The manufacturer's specs are to be used as a reference for what the system pressures should be operating at. The difference in values will not change how the system should be charged. According to the install manual, the contractor will need to add 0.6 ounces of refrigerant for every foot of liquid line further than 15 feet. Once the additional refrigerant is added, the contractor will need to perform a superheat or subcooling calculation to verify the unit is operating and charged properly."

I gotta repeat this phrase:

" to be used as a reference for what the system pressures should be operating at"

What the hell did he think I was using it for, except to do just that!

BTW, Alpine says the only way to add refrigerant is by weight in heat mode. Tech says he has done superheat/subcooling check at 60 F but would prefer 70 F.

It's 40 F here.....

I'm beginning to think the only solution to the noisy machine is to sell tickets to a "heat pump bash". $100 for the first swing with a baseball bat at the thing $95 for the second $90 for the third etc etc The person who puts it completely out of it's misery will get their ticket money back.

Afterwords we'll take it out to the country and roast it on a huge bonfire.

I know quite a few people who would just love to get their frustrations out.

Thanks for input.

My HVAC tech says it should be about 350/100 or so for my heat pump. He has stated to throw out Goodman sheets. I'm awaiting his return right now to troubleshoot problem. He thinks unit was factory overcharge as only 6 oz was added for additional line length.

Here's the response from Alpine when I questioned the strange specs in three emails:

"The manufacturer's spec sheet is based of of ARI industry testing and should be correct. You have to note that your pressures will vary depending on your outdoor and indoor humidity along with the amount of air flow and the and charge the system has. These specs indicate what the correct pressures should be based on the delta T (or temperature drop across the evaporator coil) and the outdoor temperature. If your pressure seem off based on the outdoor temp, I would first look at delta T to see if it's correct."

and

"The manufacturer's specs are to be used as a reference for what the system pressures should be operating at. The difference in values will not change how the system should be charged. According to the install manual, the contractor will need to add 0.6 ounces of refrigerant for every foot of liquid line further than 15 feet. Once the additional refrigerant is added, the contractor will need to perform a superheat or subcooling calculation to verify the unit is operating and charged properly."

I gotta repeat this phrase:

" to be used as a reference for what the system pressures should be operating at"

What the hell did he think I was using it for, except to do just that!

BTW, Alpine says the only way to add refrigerant is by weight in heat mode. Tech says he has done superheat/subcooling check at 60 F but would prefer 70 F.

It's 40 F here.....

I'm beginning to think the only solution to the noisy machine is to sell tickets to a "heat pump bash". $100 for the first swing with a baseball bat at the thing $95 for the second $90 for the third etc etc The person who puts it completely out of it's misery will get their ticket money back.

Afterwords we'll take it out to the country and roast it on a huge bonfire.

I know quite a few people who would just love to get their frustrations out.

- posted on February 20, 2009, 12:46 am

Ok, Jean, Im probably going to hate myself for doing this, ESPECIALLY since it seems you purchased it from alpine home air but here goes. Since I wasnt completly paying attention and Im not going to search back for it..............tell me again What is the EXACT model and serial of the outdoor unit AND the indoor unit. When, approximately, was it installed. Then I take it that your problem is noise during the defrost cycle? Bubba

- posted on February 20, 2009, 3:13 am

wrote:

Mea culpa. You won't beat on a guy when he's down, will you? ;)

Goodman: GSZ130241A heat pump - 2 Ton R410A w/ piston flowrator and aux heat thermostat set at 25 F. (I added crankcase heater to prevent migration and help with cold starts. Lowest recorded temp here was 15 F in 1955. It got down to 20 or so for a week this winter.)

ARUF182416 air handler w/ piston flowrator - 3 speed fan w/ 5KW heat strip.

(Don't have serial numbers handy but can get them tomorrow if necessary)

Oct 2008 - commissioned Nov 2008

It sounded like this but is getting WORSE. I'm afraid it may be slugging.

http://www.youtube.com/watch?v=9gfnmVB5q3c

The unit ran fairly quiet until recently. I'll take a video tomorrow and upload to youtube.

Here's what I've checked out:

Airflow check using 5 KW aux heater strip w/o heat pump: Air handler tested w/ ACTUAL measured voltage/current to strip: 237 VAC* / 20.0 A = 4.74 KW
CFM = KW X 3514 X 1.08 / *TR
Hi speed: 19 F temp rise 74 to 93 = 947 CFM
Mid speed: 21 F temp rise 72 to 93 = 857 CFM
I haven't measured static pressure but have provided a hole for HVAC
tech if he wanted to check. Hard to get at with downdraft unit. He
looked at my figures and install and seems satisfied.

These match figures I did at install time. I had the unit running good on auxiliary heat for several weeks while waiting for HVAC guy to do the brazing (used nitrogen), purge (500 micron) and 6 oz top up for line length. He added filter w/o refrigerant addition.

Heat pump (about 40 F outdoor temp) w/o heat strip: BTU = CFM x TR / 1.08 Using 856 CFM I came to 20,631 BTU for temp rise 72 to 98

New HVAC tech came and did a quick check several days ago. I'm waiting for him to come back and start a full diagnoses. His first plan of attack is to remove refrigerant.

Outside temp 40 - inside temp 72 Hi PR 410 / Lo PR 96 Discharge temp 158 and current 7.9 (these are from memory - might not be correct - I didn't write them down). The Hi PR dropped a bit when we upped fan speed.

This fellow is different from original installer who insists initial unit pressures were OK and the current noise is "normal". Unfortunately, I have no record of these. :(

Mea culpa. You won't beat on a guy when he's down, will you? ;)

Goodman: GSZ130241A heat pump - 2 Ton R410A w/ piston flowrator and aux heat thermostat set at 25 F. (I added crankcase heater to prevent migration and help with cold starts. Lowest recorded temp here was 15 F in 1955. It got down to 20 or so for a week this winter.)

ARUF182416 air handler w/ piston flowrator - 3 speed fan w/ 5KW heat strip.

(Don't have serial numbers handy but can get them tomorrow if necessary)

Oct 2008 - commissioned Nov 2008

It sounded like this but is getting WORSE. I'm afraid it may be slugging.

http://www.youtube.com/watch?v=9gfnmVB5q3c

The unit ran fairly quiet until recently. I'll take a video tomorrow and upload to youtube.

Here's what I've checked out:

Airflow check using 5 KW aux heater strip w/o heat pump: Air handler tested w/ ACTUAL measured voltage/current to strip: 237 VAC

These match figures I did at install time. I had the unit running good on auxiliary heat for several weeks while waiting for HVAC guy to do the brazing (used nitrogen), purge (500 micron) and 6 oz top up for line length. He added filter w/o refrigerant addition.

Heat pump (about 40 F outdoor temp) w/o heat strip: BTU = CFM x TR / 1.08 Using 856 CFM I came to 20,631 BTU for temp rise 72 to 98

New HVAC tech came and did a quick check several days ago. I'm waiting for him to come back and start a full diagnoses. His first plan of attack is to remove refrigerant.

Outside temp 40 - inside temp 72 Hi PR 410 / Lo PR 96 Discharge temp 158 and current 7.9 (these are from memory - might not be correct - I didn't write them down). The Hi PR dropped a bit when we upped fan speed.

This fellow is different from original installer who insists initial unit pressures were OK and the current noise is "normal". Unfortunately, I have no record of these. :(

- posted on February 20, 2009, 8:55 pm

I hate to break it to ya Jeanuis but your calculations are wrong.

BTUH = I X E X 3.412

20a x 237v x 3.412 = 16172.88 BTUH

CFM = BTUH / temp rise X 1.08 @ sea level. The constant, 1.08 drops slightly with altitude.

19 x 1.08 = 20.52 16172.88 / 20.52 = 788.15 CFM on high speed.

16172.88 BTUH is electric heat not mechanical refrigeration BTUH.

- posted on February 20, 2009, 9:55 pm

On Fri, 20 Feb 2009 15:55:01 -0500, The King

I agree. But your calculations are also wrong so there is no need for insults.

I am not the HVAC expert. That is why I'm asking questions in this ng.

Your formula doesn't agree with mine....

I've gone back to check my original formula:

At sea level (I can walk to the beach):

TR = kW x 3412 x 1.08 / CFM

(cross multiply to get CFM)

CFM = kW x 3412 x 1.08 / TR

CFM = 20 x 237 x 3412 x 1.08* / TR
CFM = 4.74 x 3412 x 1.08 / *TR
CFM = 17466.7104 / TR

Therefore:

@ 21 F temp rise (mid-speed) CFM = 17466.7104 / 21 = 831.75

@ 19 F temp rise (hi-speed) CFM = 17466.7104 / 19 = 919.26

I've gone back to look at calculations I did back in Nov and these agree.

Any comments?

Thanks. That appears to be where I got the 3514 from. I don't know how I slipped it into the formula for original CFM this time. I've been taking a crash course in understanding HVAC so give me a break.

Is this correct?

I agree. But your calculations are also wrong so there is no need for insults.

I am not the HVAC expert. That is why I'm asking questions in this ng.

Your formula doesn't agree with mine....

I've gone back to check my original formula:

At sea level (I can walk to the beach):

TR = kW x 3412 x 1.08 / CFM

(cross multiply to get CFM)

CFM = kW x 3412 x 1.08 / TR

CFM = 20 x 237 x 3412 x 1.08

Therefore:

@ 21 F temp rise (mid-speed) CFM = 17466.7104 / 21 = 831.75

@ 19 F temp rise (hi-speed) CFM = 17466.7104 / 19 = 919.26

I've gone back to look at calculations I did back in Nov and these agree.

Any comments?

Thanks. That appears to be where I got the 3514 from. I don't know how I slipped it into the formula for original CFM this time. I've been taking a crash course in understanding HVAC so give me a break.

Is this correct?

- posted on February 20, 2009, 10:35 pm

This should be (20 x 237 / 1000) to change to kW or use 3.412 (same end result) Sorry for slip up......

- posted on February 21, 2009, 1:55 am

On Fri, 20 Feb 2009 18:52:09 -0500, The King

Here's where I got my formula:

http://www.ncweb.com/~jsbuilders/aruf-aepf%20install.pdf

INSTALLATION & OPERATING INSTRUCTIONS FOR ARUF, ARPF, ADPF, AEPF SERIES AIR HANDLER

page 5

HEAT KIT NOMINAL kW CFM 3 5 6 8 10 15 20 21

600 18 28 35 41 800 13 21 26 31 42 1000 11 17 21 25 34 50 1200 9 14 18 21 28 42 56 62

230/1/60 Supply Voltage - Temperature Rise Table °F

Note: For installations not indicated above the following formula is to be used: TR = (kW x 3412) x (Voltage Correction) x 1.08 / CFM

Formulas can be rearranged to find different unknowns. If this one cannot, then it has been "fudged".

As you can see, the above chart shows that temp rise of 21 corresponds to 800 cfm. A temp rise of 19 would put it at approx 900 CFM. This is in agreement with my calculations. In point of fact, I could have used the chart alone to check airflow and not bothered with formula.

I can only work with what I've been given. If you can give me a URL to prove this data sheet wrong, I will gladly contact Goodman.

BTW, the HVAC tech has looked at the air handler and says it is OK. Clean with good airflow and suitable intake location.

The 2 ton unit could have been smaller. The aux heat strip was only activated for 3 or 4 days this heating season. I think I will add an 8 inch duct from the plenum (and corresponding air return) to heat a small addition, 150 sq ft, that is currently heated with a 1.5 KW wall unit. This will increase the airflow which is OK.

I was told by HVAC people that 400 CFM per ton is required but here is a site that calls for up to 500:

http://www.gemplumbing.com/lmlb_heat_pump_improve_performance.html "There should be about 400 to 500 cubic feet per minute (cfm) airflow for each ton of the heat pump's air-conditioning capacity. Efficiency and performance deteriorate if airflow is much less than 350 cfm per ton."

Here's another URL that is of interest to me. My HVAC guy thinks that the unit may have been factory overcharged.

http://www.gemplumbing.com/lmlb_heat_pump_adjusting_charge.html "For satisfactory performance and efficiency, a split-system heat pump should be within a few ounces of the correct charge, specified by the manufacturer."

Here's where I got my formula:

http://www.ncweb.com/~jsbuilders/aruf-aepf%20install.pdf

INSTALLATION & OPERATING INSTRUCTIONS FOR ARUF, ARPF, ADPF, AEPF SERIES AIR HANDLER

page 5

HEAT KIT NOMINAL kW CFM 3 5 6 8 10 15 20 21

600 18 28 35 41 800 13 21 26 31 42 1000 11 17 21 25 34 50 1200 9 14 18 21 28 42 56 62

230/1/60 Supply Voltage - Temperature Rise Table °F

Note: For installations not indicated above the following formula is to be used: TR = (kW x 3412) x (Voltage Correction) x 1.08 / CFM

Formulas can be rearranged to find different unknowns. If this one cannot, then it has been "fudged".

As you can see, the above chart shows that temp rise of 21 corresponds to 800 cfm. A temp rise of 19 would put it at approx 900 CFM. This is in agreement with my calculations. In point of fact, I could have used the chart alone to check airflow and not bothered with formula.

I can only work with what I've been given. If you can give me a URL to prove this data sheet wrong, I will gladly contact Goodman.

BTW, the HVAC tech has looked at the air handler and says it is OK. Clean with good airflow and suitable intake location.

The 2 ton unit could have been smaller. The aux heat strip was only activated for 3 or 4 days this heating season. I think I will add an 8 inch duct from the plenum (and corresponding air return) to heat a small addition, 150 sq ft, that is currently heated with a 1.5 KW wall unit. This will increase the airflow which is OK.

I was told by HVAC people that 400 CFM per ton is required but here is a site that calls for up to 500:

http://www.gemplumbing.com/lmlb_heat_pump_improve_performance.html "There should be about 400 to 500 cubic feet per minute (cfm) airflow for each ton of the heat pump's air-conditioning capacity. Efficiency and performance deteriorate if airflow is much less than 350 cfm per ton."

Here's another URL that is of interest to me. My HVAC guy thinks that the unit may have been factory overcharged.

http://www.gemplumbing.com/lmlb_heat_pump_adjusting_charge.html "For satisfactory performance and efficiency, a split-system heat pump should be within a few ounces of the correct charge, specified by the manufacturer."

- posted on February 21, 2009, 2:35 am

snip

CFM = volts x amps x 3.412 / 1.08 x temperature rise. Do the math

Your answer should be 735 CFM. If not you get another F.

You are misinterpreting the information from Goodman.

I'm honing my people skills so I can teach this shit and get out of the truck. How 'em I doin? :)

CFM = volts x amps x 3.412 / 1.08 x temperature rise. Do the math

Your answer should be 735 CFM. If not you get another F.

You are misinterpreting the information from Goodman.

I'm honing my people skills so I can teach this shit and get out of the truck. How 'em I doin? :)

- posted on February 21, 2009, 3:11 am

On Fri, 20 Feb 2009 21:35:10 -0500, The King

How can I be misinterpreting their data if I have a TR of 21 and look at their own chart and it shows 800 CFM for a 5 kW heater.

Improving. You just have to have more patience with the "great unwashed"....

How can I be misinterpreting their data if I have a TR of 21 and look at their own chart and it shows 800 CFM for a 5 kW heater.

Improving. You just have to have more patience with the "great unwashed"....

- posted on February 21, 2009, 3:50 am

chart at 5KW. Interpolate a 19 dt and a 4.7 kw to the chart, mix em up and throw em round and you get 788.

If you keep this up I'm going to have a shot of whiskey and nobody likes me then...

- posted on February 21, 2009, 4:13 am

On Fri, 20 Feb 2009 22:50:16 -0500, The King

919 was a calculation done with air handler at HI-speed and TR 19 831 was a calculation done at Mid-speed and TR 21

It all depends on what Goodman means by "nominal". The HKR heater package says "5 kW nominal" when it is in reality 4.75 kW @ 240 VAC

Better send the wife and kiddies to gramma's for the evening......

I would still like a URL for your formula. I think you might be right and Goodman wrong. It would not be the first error I've found in their stuff.

919 was a calculation done with air handler at HI-speed and TR 19 831 was a calculation done at Mid-speed and TR 21

It all depends on what Goodman means by "nominal". The HKR heater package says "5 kW nominal" when it is in reality 4.75 kW @ 240 VAC

Better send the wife and kiddies to gramma's for the evening......

I would still like a URL for your formula. I think you might be right and Goodman wrong. It would not be the first error I've found in their stuff.

- posted on February 21, 2009, 3:17 am

V x A = watts

20 x 237 = 4.741 KW

Move to the left of 5KW (that's between 3 and 5) and interpolate where 4.7 is and drop down to the closest cfm that has a 19 dt in the range. We are using 19 therefore 19 falls between 13 and 21 on the 800 line. That works out to be less than 800.

If you were to use a 19 dt between 17 and 21 on the 1000 cfm line and go up, you will intersect at a much higher btu range than you have. Comprende?

Well my wife popped in and was peering over my shoulder while I was looking at the chart. She asked what I was doing and I explained what the numbers on the chart were then I asked her what would the CFM be at 4.7KW and a 19 dt.

She got an A because she said a little less than 800 cfm. :)

Ok that's it ,you can lead a horse to water.. but my wife just popped back in and laughed at me sayin "are you still tryin to explain it to that dip shit" ? lol

She's right there's no use beating my head into your brick wall.

Good Luck dude.

- posted on February 21, 2009, 3:44 am

On Fri, 20 Feb 2009 22:17:47 -0500, The King

I know. That's why they label the HKR kit as "5 kW nominal" on the package. BTW, we're now getting into semantics. ;)

If your formula is correct the Goddman formula on this page should be:

TR = (kW x 3412) x (voltage correction) / (CFM x 1.08)

If they used their formula to produce the graphs, the results would reflect mine.

I know. That's why they label the HKR kit as "5 kW nominal" on the package. BTW, we're now getting into semantics. ;)

If your formula is correct the Goddman formula on this page should be:

TR = (kW x 3412) x (voltage correction) / (CFM x 1.08)

If they used their formula to produce the graphs, the results would reflect mine.

- posted on February 21, 2009, 2:41 am

On Fri, 20 Feb 2009 18:52:09 -0500, The King

Is your formula ordered as follows?

1) A* / B x C: eg. 8 / *4 x 2 = 4
or
2) A* / (B x C): eg. 8 / *(4 x 2) = 1

Remember your math rules from school?

Rule 1: First perform any calculations inside parentheses. Rule 2: Next perform all multiplications and divisions, working from left to right. Rule 3: Lastly, perform all additions and subtractions, working from left to right.

Is your formula ordered as follows?

1) A

Remember your math rules from school?

Rule 1: First perform any calculations inside parentheses. Rule 2: Next perform all multiplications and divisions, working from left to right. Rule 3: Lastly, perform all additions and subtractions, working from left to right.

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