please help with A-coil, losing my mind

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Old 02-12-11, 04:38 PM
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please help with A-coil, losing my mind

we have a oakwood mobil home built in 2000, it has a split system heat pump. The furnace is a nordyne, the outside unit is a goodman 3 ton. NOW, The A-coil inside the house is leaking, had to have it gassed up twice this year. The tech that gassed up the system did a leak check and the A-coil is leaking. The outdoor goodman unit may be 10 years old but is still in great working condition wich is good because i can not afford a whole new system right now. The problem is the A-coil, all the stickers with the brand name and part number are long gone, so we dont know if the A-coil is also a goodman like the outdoor unit or if its a nordyne/intertherm like the furnace it sits on. So far, any un-cased A-coils ive looked at that look anything like what i have is intertherm, has the lines coming in on the left side and all. SO, i am leaning towards that, BUT, they have several different 3 ton A-coils that look identical but have different size orifice, anyone know what size orifice i need? again, i have a goodman 3 ton unit and the new intertherm A-coil is also 3 ton, so the tonnage will match. I have no idea what seer the 10 year old goodman outdoor unit is, the goodman unit is model#cpke36-1a, serial#0004548722, mfa#213-93-e, part#14932-054.

I have a friend that does HVAC that is going to install the new A-coil when i get it but wants me to go ahead and get it and have it ready, but again, not sure of wich 3 ton A-coil to get because of not knowing wich orifice size i need? It does not use a TXV on this, just the orifice. any help will be appreciated.
thanks
 
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Old 02-12-11, 06:46 PM
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A matching system is Very important with heat pumps, but if this is not an option right now the Nordyne 3 ton A coil with a TXV will work. Verify the refrigerant used in your outdoor unit. (R410a or R22)
 
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Old 02-13-11, 09:22 AM
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well, the current A-coil does not use a txv valve, it uses an orifice. It uses r-22 also. Im at witts end, the company on ebay that im dealing with that sells these mobil home a-coils told me that the only one they sell that they know is compatible with a goodman HP is this mortex brand a-coil they carry and it will accept r-22 or 410, i told them i would rather have the intertherm they sell because its cheaper, they said it would work also, and i think thats what i have now too, so i see they sell several intertherm 3 ton a-coils that all look the same but different part numbers, they say the only difference is the size of the orifice, so i ask them wich one do i need, they come back with saying the one they know for sure will work with goodman unit is the mortex, ok, i want the intertherm, even if i got the mortex i would still need to know what size orifice to use..i just do not know what to do, my nerves are shot! all i want to do is replace the a-coil and be done and go as long as it will last so i can start saving for a whole new heat pump in the future.
 
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Old 02-13-11, 09:37 AM
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You need an expansion valve, especially with two different brands.
The old coil should have had one but someone took a shortcut at your expense.

There is no method for calculating the correct oriface to match two different brands.
 
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Old 02-13-11, 09:42 AM
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I would also recommend a TXV. On the subject of metering device, your old coil should have a piston (orifice) in place. remove it and it may be the correct type to go in the new coil, if not it should have numbers on it indicating a size.
 
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Old 02-13-11, 10:26 AM
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yes, my original has an orifice only (piston), no txv, so are you saying i can just get an a-coil that has a txv and it will work even though the original does not use a txv, only the piston? I did think about just using the piston from the old A-coil in the new A-coil, but how do i know that would still be the correct piston (orifice) size being the new A-coil is not the same identical one as the original?
 
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Old 02-13-11, 10:53 AM
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the metering device is sized/based on the outdoor unit and has nothing to do with the indoor unit other than not all indoor coils us the exact same piston design. A TXV can be used with your system even though it did not have one originally and this has been known to actually improve efficiency of cooling as well. The TXV would have to be for a Heat Pump though as the refrigerant flows in both directions on a heat pump. Not all are for heat pumps and it also has to be for your refrigerant.
 
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Old 02-13-11, 10:53 AM
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A TXV can increase the efficiency of a matching system 1/2 SEER.
A fifty dollar TXV is going to control refrigerant flow better than a two dollar oriface.
 
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Old 02-13-11, 04:17 PM
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ahh, so even though my original a-coil uses an orifice instead of a TXV, i CAN indeed use a txv on the new a-coil and do away with the orifice? If so, will any txv go on the new a-coil or are they brand specific or? I think some of those nordyne a-coils i looked at had the txv valve with it, so that would be ok as long as its for r-22 like i use? In other words, if i get the nordyne 3 ton a-coil that comes with a txv valve, it will work with my 10 year old goodman 3 ton unit? There is no certain size txv valve to get or anything?
 
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Old 02-13-11, 04:21 PM
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one more thing as far as the orifice size, so no matter what size or brand of a-coil, the orifice is still determined by the outside goodman unit? I thought the orifice size was used to match a different tonnage a-coil to a different tonnage unit? for example, to match a smaller a-coil to bigger outside unit or vise versa even tho your not supposed to do that..
so anyhow, are you saying that whatever size orifice is in my original a-coil needs to be the same size thats in the new a-coil no matter what brand, shape or whatever it is? if so, that helps a bunch because i can find out that when removing the old a-coil, just wish i knew now though so i could just order the new a-coil that has that correct sized orifice..
 
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Old 02-13-11, 04:52 PM
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In other words, if i get the nordyne 3 ton a-coil that comes with a txv valve, it will work with my 10 year old goodman 3 ton unit?
yes, the size of a TXV is by the tonnage of the outdoor unit.
one more thing as far as the orifice size, so no matter what size or brand of a-coil, the orifice is still determined by the outside goodman unit?
yes, the outdoor unit should have been shipped with the correct orifice to use with a goodman coil regardless of the size of the coil (within limits) and that should be what is being used currently.
I have a friend that does HVAC that is going to install the new A-coil when i get it but wants me to go ahead and get it and have it ready
He should have been able to tell you all this if he were knowledgeable in the HVAC industry and were EPA certified.
 
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Old 02-13-11, 05:09 PM
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ok thanks all, think im getting this. only thing i dont know about is what coil to get, the company ive been talking to is saying they know for a fact that the MORTEX mobile home A-coil they sell is compatible with a goodman unit but they dont know if the intertherm a-coil they sell is or not, but im thinking that my original is indeed an intertherm a-coil that matches the intertherm/nordyne furnace because it looks the most like what i have..regardless, your saying either one will work as long as its a 3 ton a-coil because the outside unit is 3 ton, and either get one with a txv, OR, one with the same size orifice as my original, correct? again thanks all for your help, i want to understand all this, love t learn.
 
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Old 02-13-11, 05:20 PM
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your saying either one will work as long as its a 3 ton a-coil because the outside unit is 3 ton, and either get one with a txv, OR, one with the same size orifice as my original, correct?
Yes, get a 3 ton coil. If you get one with a TXV ensure it is for R22 and that it is for a Heat pump (should have a check valve). One thing to note, when adding a txv is that I would also add a hard start kit if your Heat pump does not already have one. Or get one with an orifice, either the correct size orifice or at least one that uses the same style piston as your old one uses (not all pistons are the same design)
 
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Old 02-13-11, 05:42 PM
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ok thanks, still dont understand the company that has the a-coils saying that they know for sure the mortex a-coil they sell is compatible with a 3 ton goodman unit because it doesnt have a txv! so it uses an orifice, so how do they know its the correct size? and whats a hard start kit? and how do i know if my unit already has one?
 
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Old 02-13-11, 05:48 PM
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hard start is an extra starting capacitor and relay kit and is needed with reciprocating compressors with a TXV. T0-5 is what I use.

I dont know what that company is talking about, you need the dimensions of the old coil to know if it will fit where there old coil went and the tonnage and the refrigerant. that is all you really need, I'm not sure what they are talking about.
 
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Old 02-13-11, 06:07 PM
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ok thanks, i think i just want to find out what piston size goodman recommends for this 10 year old unit and just get the new a-coil with that size piston, anyone know where i can find out that info being the unit is 10 years old? i found some spec sheets on the web but didnt see my model on there, probably out dated. also saw on that spec sheet they needed the btu of indoor a-coil to pick the correct size orifice to the outside unit, anyone know what btu a 3 ton a-coil is?
 
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Old 02-14-11, 05:21 AM
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hvactechfw are you saying that a Carrier piston 101 is the same as every other brands 101 piston?

Are you saying that a Carrier piston would fit into a Trane flow rator?

I would disagree with both statements. I doubt that that was your meaning but it kinda reads like that.

If the old coil was a Nordyne, and the new coil is a Nordyne the old piston should fit into the new coil unles there has been a major change in design. I believe the brand of the old coil is uncertain at this time.
 
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Old 02-14-11, 10:41 AM
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no, that is not at all what I'm saying. Houston. I am saying that as long as the diameter of the hole is the same then it should work. Sorry for the confusion. Pistons made by different manufacturers are typically not of the same design, some are when you look at cross brands such as amer. standard and trane, or carrier, and bryant, or nordyne and gibson.

The brand of the old coil is a mystery at this point, you can't tell anything just by looking at them. there should be a rating plate/sticker on the delta plate or possibly on the pan. I'm not sure the OP has take the door off to really look for this. I also have a concern over the so called hvac guy that is going to do all this for the OP and am wondering why he hasn't helped with getting the correct coil and piston/TXV. I know that even if I was doing something for a friend, I wouldn't do it if it weren't done right with the correct parts and so on......
 
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Old 02-14-11, 05:44 PM
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ok guys, I have indeed looked extensively for any stickers/numbers on the a-coil, there is nothing there anymore, im thinking the rust probably let the sticker go and it got sucked away through the furnace, ive searched the entire closet up and down for it and its gone, there is nothing tamped on the a-coil case anywhere either. all i know is that as far as looking at all the brands, it resembles a nordyne/intertherm the most, and also, the connections and drain are all on the left hand side wich i BELIEVE is a mobil home specific type thing being most are hooked up on the right side, but all the ones that are advertised for mobile homes have the hook ups abd drain on the left, like mine. Also, the mobile home furnace that the A-coil sits on is a nordyne/intertherm so im guessing they also used a nordyne intertherm a-coil, as far as ive seen, goodman never made a mobile home specific a-coil that is plumbed on the left side. As far as my HVAC freind that is going to install it, he is doing it as a favor for free besides cost of freon as long as i get the coil, he is busy so im researching the coil myself. again, things are very hard right now and i just do not have the money to get a company to just bring their a-coil out thats been jacked up in price 3 times and pay the charges to install, i just dont have the money. all i want to do is get the a-coil changed out and go as long as the system will last so i can save for a whole new system.
 
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Old 02-14-11, 09:48 PM
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i to live in a double wide mobile home. I matched up a 3 ton york to a 3 ton nordyne/intertherm a-coil . my cooling and heating cost has always been low. You must know what seer your heat pump is to match your coil. Nordyne will over build their coils so you will have to watch out . Count the layer of coils on your a-coil, is it 2 or 3 layers. My nordyne 3 ton coil by part number is what nordyne calls a high efficiency a-coil but it is actually a 3.5 ton a-coil. my system has a orfice on the a-coil and works fine. Make sure your guy checks out the heat pump to see if it produces the pressures under a load, all you do is cover up the fan while running and check amps and pressure. you may want to do a acid test to make sure your condensor is ok

your heat pump is a 10 seer high efficiency

http://www.myplanet.net/acdinc/cpkespecs.pdf
 

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Old 02-19-11, 04:12 PM
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Lee, thanks for posting those specs. Still have not found anything on what size piston goodman wants, anyone know any other website that would know?
 
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Old 02-20-11, 07:01 AM
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I found it in my johnstones book!!!!!!!!!!!!!! CPKE36-1 B1789874 is the goodman number. Product Details

this piston for a 3 ton coil is .071-.074 this information is listed out here PISTON KIT CHART
go to CPLE 36-1 and this has that piston kit number and for 3 ton coils it lists .071-.074
 
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Old 02-20-11, 11:58 AM
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thanks!! wonder why they dont have a certain recomendation, rather they say .71-.74? The intertherm im looking at has a .75, would that be ok or?
 
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Old 02-20-11, 02:23 PM
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well, you are close, better if you were what it calls for, but understandable as you are not using a recommended (matched) coil with your heat pump.
 
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Old 02-20-11, 03:47 PM
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so is goodman saying it doesnt matter as long as its .071 to.074? seems like they would say one specific size..thats what i dont understand
 
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Old 02-20-11, 03:52 PM
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I gave you what they have listed from goodman, beyond that it is your choice. I would go with a TXV personally..... But you now have the information to make your own choice...... I think you are over thinking the situation. plain and simply you are using an unmatched coil so for it to be within spec is going to be hard to do no matter which size you choose because the coil and the outdoor unit are not rated together. A TXV would overcome this.
 
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Old 02-21-11, 03:34 PM
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I think the best bet, is to remove the airhandler from inside the house and install a packaged heat pump.
I've always hated those noisy mobile home split systems. Another advantage is, you can build a pantry or closet in place of the indoor unit.
 
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Old 02-21-11, 04:54 PM
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this would be so much easier if the dang numbers were still on the original a-coil. I dont know what goodman would want the unit matched to being that mobil home a-coils are plumbed on the left side, as is mine, and goodman never made mobil home a-coils..but whatever in the heck brand i have worked efficiently. I guess since i either choose to eat or replace my entire heat pump system since there is no right a coil for it we will just burn up this summer.lol.im being told i can not use a txv with this heatpump because i will lock up the compressor, so there goes that idea.
 
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Old 02-21-11, 04:56 PM
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No, that is not true!!!!!!!!!!! besides you have the information for the piston size.
 
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Old 02-22-11, 01:59 PM
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i know but unsure of wich orifice to have the a-coil seller install, do i just tell them to install one anywhere from a .071 to .074? they probably want an exact size not just a general range..i dont know. Then, the intertherm coil im looking at comes with a .075, and the seller is saying goodman wants a .076, so im confused still
 
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Old 02-23-11, 08:26 AM
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well, ive been talking with the manager of a local hvac company and hes going to take care of me, but now im seeing ice on the outdoor unit, yet it still seems to be heating fine, so im not sure if it has just leaked the refridgerant down enough to freeze up the outdoor unit or if the defrost cycle isnt coming on or what..is there anything else that will cause the outside unit to ice up besides low refridgerant or the defrost cycle not coming on?
 
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Old 02-23-11, 04:52 PM
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Lightbulb

i got home from work and messed with it some, ok, i turned heat on and it blew warm like its supposed to, i felt the a-coil and it was very warm as should be, looked outside and the outside unit was frosting up like it did last night, nothing as bad as it was last night though. so i switched it to AC, i watched the a-coil and frost built up on the 2 lower coils of the a-coil and on the line going into the a coil, so its not getting completely iced up, just a little on the a-coil with AC going and the outside unit gets some with the heat going. Can these get just some frosting on them if the refridgerant is a LITTLE low? When it was real low last summer the a-coil was a solid chunk of ice, its nothing that bad now, just some frosting, same with outside unit. Normally no components get any frost on them ever, so, can it be a little low on freon causing this?
 
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Old 02-23-11, 04:55 PM
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it could be low, it could be a restriction, it could be an air flow issue. If left run for a long time this is when the coils will turn to a block of ice, the more ice, the more airflow is diminished, the faster the ice will grow.
 
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