I'm a home energy auditor, and I have noticed quite a few HVAC companies use Aspen coils. What is the story behind these? How can Aspen make a coil that is better than the coil from the condensor manufacturer, or is it simply a cheaper alternative? Also the higher SEER combos seem to have '+TDR' in the model number. What does this mean?
We only use them when space is an issue.....they make coils that are higher seer, yet shorter in height.....we always throw our own equipment's txv on them as well....they are a good coil....not sure they are that much cheaper or that much better, but definitely a very good coil when size is an issue......
I need a new signature.....
Good question! I believe aspen simple makes coils to the manufactures specifications, not necessarily better. I have seen a lot of them matched up to carrier and Lennox condensers in track houses.
I would put an Aspen coil up against "ANY" coil mfg. also they are not cheap! I can buy a RUUD box coil cheaper than the Aspen box coil. I have heard the TDR means that the coil gets it full efficiency with an installed Time Delay Relay on furnace or air handler, unless someone else has a better idea of what TDR means.
Originally Posted by jdaley
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TDR is referring to a time delay relay, most furnaces and air handlers now have a built in blower delay. The reason is so you build a colum of liquid refrigerant to the coil before the blower starts. This is not necessary if you have an ECM motor and/or non-equalizing TEV. Think back to when Carrier and others used liquid line solenoids.
Aspen is a good coil I use them on Goodman installs because i do not like the Goodman coils. For years Aspen made coils in dimensions that were direct replacement for OEM coils.
Legitament mfrs.,have not built the three row coils that off brand mfrs.
builit until the tax credit came about,be careful of the higher static PD of coils that rate higher,many brands are now building these too.
Thanks for the answers.
What is a txv?
always throw our own equipment's txv on them as well
My York distributor went to an Aspen coil when no York coil could make the AHRI tax credit certification in the 4-ton DFHP with VS modulating furnace. Had great numbers but when I got the certificate from Aspen the HSPF was rerated down from 10.10 to 8.95. Not a problem since I have the modulating furnace and dual fuel. However, just checked in the middle of the install and AHRI no longer has a rating for this combo. Scary. I believe I read that AHRI has been overwhelmed with rating all kinds of combos and since they can't randomly test they are taking down some certs.
Get that Aspen, and I imagine any other 3rd party coil, tax credit certificate in hand before you authorize installation. And of course the SEER/EER/HSPF (for HP combo) are written right on your proposal, right?
By the way, my coil is a 5-ton on a 4-ton DFHP. It is huge compared to the previous 10 SEER coil. Just barely got it in the vertical space even with a 33" high furnace versus 40"+ for the previous furnace.
No wrong answers that I can see, although I'm not sure what is meant by "Legitament" (legitimate?) manufacturer means. I would like to reiterate and clarify a few things though;
Aspen coils as well as all aftermarket coils (coils that are not manufactured by the manufacturers' of the outdoor units) have a lieniency in there ratings that give them an unfair advantage over equipment manufacturer's ratings. Equipment manufacturer's must test their coils in actual physical conditions with their outdoor units and are allowed a 5% margin of error. After market coil companies only need to do a computer simulation testing and are allowed, at this time, a 10% margin of error. That margin of error is usually what gets the aftermarket coils over the top in their ratings so they qualify for certain tax incentives and rebate credits. Can you believe this is all money driven?
Anyway, as mentioned, Aspen coils are not always less expensive. They have two major advantages; being shorter for tight applications and having higher efficiency ratings due to the way the rating system works. I have an Aspen coil connected to a Goodman heat pump on top of my oil furnace being metered with a piston and have never had a problem with it. Due to the thicker fin pack with more rows of tubing, my system has a wonderful dehumidificaiton factor.
A TDR is indeed a TDR, however, it again is for the benefit of elevating efficiency ratings by delaying the indoor air blower from turning "off", thus utilizing the last minute of heat extraction from the still evaporating refrigerant in the indoor coil. As mentioned, most, if not all new furnaces and air handlers have a TDR built in to the blower control board. Older furnaces can have TDR's wired in-line to the blower relay. Many will argue that this time delay hurts dehumidification by blowing evaporated condensate left on the coil back into the airstream. It is a valid point, but the TDR adds about a .4 SEER rating to the system which in many cases is just enough to put the system over what is needed for tax incentives or rebates.
A txv is a metering device that adjusts the refrigerant metering to the actual conditions affecting the system, in contrast to a fixed metering device which is set to an average efficiency rating at only one conditions data. If a fixed metering device is designed to be a certain efficiency with the outdoor ambient being 95 degrees (the standard rating temperature) and the indoor airflow being 75 degrees, then as the conditions go up or down from those set points, the system is either more or less efficient. Since the txv maintains the systems efficiency accuracy, they add to the overall efficiency rating in test results. Yes, there are applications where a tested piston metered system will actually be more efficient then a txv. Such an application would be in areas with a constant heat load.
Some of the efficiency boosting items and there affect on systems are;
Hope this helps.
- Txv metering increases efficiency rating with mostly advantages to the system's operation. Downside; txv's will fail as they are mechanical devices, whereas a fixed metering device cannot fail unless the system refrigerant becomes contaminated, in which case both fixed and txv metered systems would be adversely affected.
- TDR blower delay on the off cycle increases efficiency rating by about .4 SEER but can, especially in humid areas, adversely affect humidity control, thus affecting comfort control.
- Removal of compressor crankcase heater increases the overall efficiency rating of the system by about .4-.6 SEER, but can be a problem with the refrigerant oil becoming heavier during initial start ups after longer periods of shut down and on systems that operate in lower ambient temperatures. Personally, I prefer adding a crankcase heater to all heat pumps where there is not one installed. Manufacturer's use contactors that are shunted on one leg of the line voltage in order to keep the crankcase somewhat heated with the electrical current that continuously surrounds the live leg of electrical in the compressor. Since even manufacturer's who do this require crankcase heaters on long lineset applications, I suppose we can be certain that even the manufacturer's realize that this trickle charge of electrical heat energy is not very effective compared to a crankcase heater.
Government is a disease...
...masquerading as its own cure…
Ecclesiastes 10:2 NIV
Thanks for the great info. Interesting about the difference in ratings between aftermarket and 'OE' coil manufacturers. It does not seem right to me, that an Aspen coil can be used to up the SEER rating when it might be the same (or lower) than the OE coil in actual performance. Why is the rating system like this? Because it would be too difficult to actually field test all of the consdensor/coil combos with all manfacturers?
Regarding the TDR, the ~0.4 SEER increase, would that be with an air handler that has a built in time delay an ECM motor, or a PSC unit with no delay? The difference in SEER, I assume that would be strictly due to the slightly shorter run time of the blower motor for each A/C cycle? I would think with a heat pump the time delay would be crucial to avoid cold blows.
Regarding the crankcase heater, does every A/C unit have this? For a heat pump I would think this is even more necessary due to the lower outdoor temperature. Do some units have a 'smart' crankcase heater where it would only operate when the outdoor temp is below a certain level? That would make a heck of a lot of sense to me. I guess it would be advisable to turn the A/C breaker off when the cooling season is done to save this draw (What would be the approximate draw of the crankcase heater?)
Thanks for all the answers.
They pulled thousands of rating for third party coils and others ,on 7/15/2009.
Check before you buy,if you want the federal tax credit.
Robin when did they go to the RDR being on the off cycle instead of the delay on cycle originally it was for delay on.
I wasn't sure if this went through or not. ACCA was really trying to get AHRI to extend doing this to give contractors time to revamp bids with the unfair aftermarket ratings on them. Have you found verification that the lowered aftermarket ratings have gone into affect?
Originally Posted by dash
Hopefully anyone who had a system installed using an aftermarket coil has already printed out a copy of the ratings while they were qualifying for tax credits or rebates. Since we still don't know how the IRS is going to handle this tax credit, I would want to be sure I had proof that what I had installed qualified at the time it was installed.
Government is a disease...
...masquerading as its own cure…
Ecclesiastes 10:2 NIV