Replyno reason why you could not lock out high speed for cooling.
Membership Chair/ARP Committee / Professional Member*
And here I am thinking of a 50/50 TS compressor.
That way I could size the low speed for cooling only and the two stage operation for heating.
PHM
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When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
Professional Member*
no reason why you could not lock out high speed for cooling.
God Speed, Jim. We'll miss you - 2-26-23
You can.
How well it will dehumidify is the question though.
The compressor is 50/100. But your indoor coil is sized for the 100% capacity. So, in low stage cooling, you will be at 60% or so. And the latant ability is not good on a large coil with low mass refrigerant flow.
So you will need to watch your blower control.
Or, get a whole house dehumidifier also.
Member
Two air handlers perhaps? A progressive Lennox contractor here use to do it.
Sponsor & Professional Member*
Call 911! There is a teddy bear in WI lying on the floor in shock. Thanks, anyway. Regards TBOriginally Posted by beenthere
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
Professional Member*
Hmm. Then what's all the hype about great dehumidification in low stage? Is it because it runs longer and with a lower fan speed? That's my guess. I understand what you're saying, so it must be the longer run time.
Regular Guest
While the fan speed is lower, check the CFM/ton. Probably very close to second stage.
AM
God Speed, Jim. We'll miss you - 2-26-23
The better dehumidification is from the longer run time in first stage. And if the unit is oversized, you don't get that long run cycle that you need.
God Speed, Jim. We'll miss you - 2-26-23
He's designing and building his own units and system.
He is going to grossly over size his heat pump.
There is no way it will remove enough moisture.
So a dehumidifier is the only way.
What he's doing would be more headache then its worth, in Joe home owners house.
Membership Chair/ARP Committee / Professional Member*
If I use a single speed compressor heat pump, I come up short on the heating side for this area, and will eventually have to add heat by alternate means. Generally electric resistance.
So then I thought: how about a two speed compressor? The low speed capacity could be sized for the cooling load, and the high speed heating performance would be available for heating. Which would tend to minimize the use of the resistance.
It was just a thought. And who else can I ask if not you? <g>
It may all come to nothing now as no one will sell me the TS compressors out-right anyway.
I used to propose that people installed two heat pump systems - for the exact same reason - one as the back-up to the other. Plus; the redundancy of having two complete systems for AC.
I only got two takers in twenty five years and both houses are gone now. Well, only one is physically gone. The other had the systems ripped out by a new owner before I could get to them.
The contractor they called had no idea what it was and so condemned the whole install with: we've never seen this and no one in their right mind would ever work on it - you need a whole new system. This despite the fact that it worked great for years before they showed up.
We used to alter the stage one unit every year.
What a great guy the original owner was. He had a game room in his house that was probably 1000 square feet by itself. Always reached into his pocket and paid the bill in hundreds with a generous tip. Plenty of times he said: I've got to run. Help yourself to whatever you want in the kitchen, just lock the door when you go. Thanks!
PHM
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When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
God Speed, Jim. We'll miss you - 2-26-23
You should have got benny to get you one before he went into biz himself.
You could contact hvar r us 2, he should be able to get you one.
Professional Member
How bout a copeland scroll that can unload to approx. 65% and stack Rheem coils shown for 4 or 5 ton applications?
Be safe not fast. body parts don't grow back
Membership Chair/ARP Committee / Professional Member*
Rheem 3 ton 16.5 SEER HP - two speed
35,400 total cooling
1 - 25,800 = 19,350 / 6450 latent
2 - not used for cooling
1 - 24,000 @ 47 / 14,900 @ 17
2 - 33,400 @ 47 / 21,400 @ 17
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Rheem 2 ton 14 SEER HP
24,200 total cooling - 17,700 / 6500 latent
22,600 @ 47 / 14,200 @ 17
So according to the ARI matches I lose slightly on the humidity side but I gain 50% on the heating side by using the 3 ton instead of the 2 ton.
Is that loss enough to make an issue do you think? Am I missing anything important here?
PHM
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When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
God Speed, Jim. We'll miss you - 2-26-23
That depends on what your sensible load really is.
If your sensible load is 15,600, the 3 ton 2 stage won't remove enough moisture.
If its 17,000, the 3 ton 2 stage should be ok.
Those AHRI ratings are for 400 CFM per ton, so if you slow the VS blower down, you can increase its latent, and lower its sensible.
Banned
So and a bandaid,I mean dehumidifier!!LOL
Regular Guest
Man, I've been trying to do that for years. Everybody (HVAC techs) all but said I was nuts and it was impossible.
.
Membership Chair/ARP Committee / Professional Member*
Some years ago I hit on the idea of using heat pumps to do refrigeration in a warehouse. To defrost the coils I wanted to just kill the O wire to the outdoor units and so make the big Bohn evaporators heat up and melt the ice. I used a check valve parallel to the refrigeration TXV.
People screamed that I was crazy, said it would never work, and that I should just use electric heaters, or hot gas, like everybody else. So I installed the heat pumps. <g>
Worked really well and defrosted in a few minutes. <g>
The dual heat pumps idea came to me first in the 1980's when I was sort of lamenting the imbalance between the heating and cooling loads in this area. It annoyed me that I had to design for cooling and let heating just fall wherever. Using two heat pumps was the best I could come up with then. The problem was that the initial cost was too high for most people. Big Eddie didn't care - "do whatever you think is right. I know you'll do the right thing for me."
It's a funny story: when I was a young boy I had bashed his young race horse colt across the head with a 2 by 4 for kicking me. Eddie and I were sort of friends after that.
PHM
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Man, I've been trying to do that for years. Everybody (HVAC techs) all but said I was nuts and it was impossible.
.
PHM
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When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
God Speed, Jim. We'll miss you - 2-26-23
Guess that means you still don't remember him hitting you over the head with that same 2 x 4.
Banned
You could size the A/C to low stage and gain heat pmp capacity,but you give up all the advanages of two stage cooling,or add a dehumidifier,to make up for it.
Membership Chair/ARP Committee / Professional Member*
When I was small I used to walk across a big field and through some woods to get to my friend's house. Eddie built a big house, some horse stables, and pastures in that field. I still walked across it. The were horses in it and I used to pet them, feed them grass, and so forth. One young colt, big but less than a year, was curious and came over. I talked to him, rubbed his nose, rubbed his neck, etc. and he was fine.
Then as soon as I turned my back he spun around and kicked me in the shoulder with both back feet. Like a sucker-punch. Then he was all cocky and bouncing around and running his mouth. I got to the far fence and found a 2 by 4 about 5 feet long sitting behind that neighbor's garage. So I got it and went back. The colt was still all full of himself. When I got close enough I swung a home-run swing and bashed him across the side of the head. That really surprised him and he ran away.
A guy from the stables came running over and started yelling. He grabbed me and escorted me up to the big house. He was pissed off and so sure that Eddie was going to do something about it. I was pretty scared.
Turned out it was some big-deal racing colt that Eddie had paid some huge amount of money for.
The stable guy rang the bell, Eddie's wife answered and then got Eddie. The stable guy told him that I had bashed his new colt in the head with a board.
Eddie asked me if I had and I said yes. He asked me why and I said: that sonofa***** kicked me first! He was nice to my face and then when I turned to walk away he kicked me.
Eddie told the stable guy that he would handle it and took me into the house and closed the door. Then he asked to hear the whole story. I told him and then he almost smiled and said that he would have probably done the same thing. We talked for a while, he asked what my name was and where I lived. His wife brought me cookies.
After that he was always friendly to me. If he would drive by on the street he would always wave and sometimes pull over to ask how I was doing. Later I started doing some AC and heating work for him. He had some big businesses but he really laundered Mafia money for a living. He was always good to me.
PHM
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When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
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