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Ok, another arguement ensued, in regards to replacing only the outdoor unit w/out a matching indoor coil. Granted, it's best to replace both the indoor and outdoor coils altogether. But, for conversation purposes, what does it matter how high the discharge pressure is (heat pump)? As long as the compressor doesn't overload on amp draw, wouldn't it be beneficial to the homeowner?

You know, higher pressure, higher coil temp, thus higher supply temps. I know the coils are rated to handle pressures of 600psi, and I am not sure about the compressor valves. But, if the motor can handle the load, and If the valves can handle say 400 psi, why not?

Wouldn't one achieve a higher H.S.P.F.? With higher pressures at a minimal amp draw?
 

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Dude what is wrong with you? Thats the equivalent of running the air conditioner with a garbage bag over the condenser. How long do you think that will last?

How about you think beyond amps and temperatures and think of the REAL affects of overheating a system like that. How about the affects the heat will have on the refrigeration OIL over time, the windings of the compressor, etc.

just stop it. go sit down and have a lollipop and think about what your saying.:laughing:
 

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thanks for the reply. Although a little finishing school wouldn't kill a fella...;)

I did not take into consideration the effects on the oil. I do not know what temps the oil can withstand. That perhaps could be a problem. Nor do I know how much pressure the valves can handle. However, The heat on the windings should not be that bad. The refrigerant is used to cool the compressor and the ambient temp doesn't hurt matters. Theoretically, as long as the motor is running 10% within the RLA, The compressor should last "forever".

It would be interesting to see how hot the compressor got with a odt of 30 degrees, discharge press of say 300 (r-22), and system was running within the RLA.

The lollipop wasn't bad, and this was just something I thought others in the hvac field would think worthy of simply discussing. For the record, I haven't ever setup a system with the intent of running high discharge pressures. I just thought...why not?
 

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thanks for the reply. Although a little finishing school wouldn't kill a fella...;)



The lollipop wasn't bad, and this was just something I thought others in the hvac field would think worthy of simply discussing. For the record, I haven't ever setup a system with the intent of running high discharge pressures. I just thought...why not?

I am subtle to say the least.

Anyway I can tell you from experience (not done by be either!!) that I haven't had one work yet. I have run into about half a dozen units that were done like this and they all end with the same result. Unit going off on high pressure all winter.

It's all about coil size. And the reason the compressor CAN do the same work with less amp draw is by having the coil sizes to do so. Look at two different compressors in a new and old system and notice the HP and size difference. Old compressors with smaller coils were big and bulky needing more HP to do the same amount of work. Larger coils take up the slack along with more refrigerant charge as well.

Now take a new heat pump condenser with a coil thats two times the size the one taken out and a small evap coil inside. Not enough coil space to condense to a low enough pressure. Bam.

If it was able to be done some manufacturer would have said so by now because it would help them make easy retrofit sales.
 

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tall tales...

I am subtle to say the least.

Anyway I can tell you from experience (not done by be either!!) that I haven't had one work yet. I have run into about half a dozen units that were done like this and they all end with the same result. Unit going off on high pressure all winter.
experience of not knowing how to size is your problem, and doesn't mean everyone else is wrong to only change the outdoor unit.
you should take a class in commonsense.
half a dozen to figure out you dont know how is very nonsensical,, i guarantee you havent tried one single unit because your dealer had a class who told you this stuff youre running around preaching. :clap:
Now take a new heat pump condenser with a coil thats two times the size the one taken out and a small evap coil inside. Not enough coil space to condense to a low enough pressure. Bam.
They dont have heat pumps in Pa , do they? :laughing:
Besides the fact the same tonnage coil in a 13 seer from a 10-12 seer is not double in size, but may appear that way to a untrained eye or a drama queen.

If it was able to be done some manufacturer would have said so by now because it would help them make easy retrofit sales.
The wont say either way... :eek:
why? :jester:

well? :furious:

:laughing:

truth be told , they make more money telling their contractors and techs , the warranty story to help sell more complete systems of 410a
and to keep techs or contractors from thousands of warrantys from the marginal sizing mistakes made from thousands of contractors.
so they nip it in the bud.
teach this clown something someone before he runs around spewing this home made tea and baloney sandwich sales pitch.

:whistling:whistling:whistling
 

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experience of not knowing how to size is your problem, and doesn't mean everyone else is wrong to only change the outdoor unit.
you should take a class in commonsense.
half a dozen to figure out you dont know how is very nonsensical,, i guarantee you havent tried one single unit because your dealer had a class who told you this stuff youre running around preaching.
They dont have heat pumps in Pa , do they?
Besides the fact the same tonnage coil in a 13 seer from a 10-12 seer is not double in size, but may appear that way to a untrained eye or a drama queen.

The wont say either way...
why? :jester:

well? :furious:

:laughing:

truth be told , they make more money telling their contractors and techs , the warranty story to help sell more complete systems of 410a
and to keep techs or contractors from thousands of warrantys from the marginal sizing mistakes made from thousands of contractors.
so they nip it in the bud.
teach this clown something someone before he runs around spewing this home made tea and baloney sandwich sales pitch.

:whistling:whistling:whistling

There just aren't enough words to describe you. Once again back it up in facts. Then we can talk. You go around properly undersizing your condensers. What do you do when manual J says you need a larger unit?

Whats manual J?? :detective:

And not that I give a flying fu:censored: what you think but unlike you I have worked in much more that just residential and dont go to all the so called classes you think that I must have telling me not to do things. Being in industrial refrigeration you will see that alot of things can be done. To me residential is a joke because it's full of people like you. When you have a in depth knowledge of the refrigeration cycle thats all you need to tell you what works and doesn't.

But you think its all about TXV's
 

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Jerkemy ,your responses now are somewhat comical.No doubt you are a internet 'HVAC SITE TROLL'.I say this with full confidence,as you mentioned the forum ;HVAC TALK'.and i'm quite certain BALD LOONIE would have kicked your ass off that site your first post[ smokey the bear].You keep bragging how resi is such a joke,and your a big industrial fridge mech,well i'd probably say 1/2 the techs on this forum have indy experience...big f..k. whats your point..I bet you brag about how big your wiener is too! and we all know what that means don't we..Do you drive a Corvette?My point is [besides that you sound very Green and immature is ] The 1st thing i learned in this trade was don't have a ego.If i don't learn something new everday then wtf and i don't care who i learn it from.Why don't you tell us the last thing that stumped you! If u can't .....well...............we all know!! can't wait GOOF!! [ ya u probably have no clue] its not Disney...
 

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So it is ok for someone to say we are all hacks because we dont mismatch systems but I can't state it in return?

Get bent. I don't BRAG about my industrial background nor do I actually think 1/2 the techs here have experience in that. Especially when someone is ignorant and arrogant enough to think they can reinvent the wheel against what other established experienced techs have found to not work.

The only TROLL I see in this forum is mr pro here who has his own crappy ass site that can't attract anyone so he comes to other sites to try to boost traffic on his.

When either one of you have facts to back up the crap you spew feel free. I actually come here to learn and as the OP stated it was a conversation which mrpro decided to but in on me because he wasn't happy starting with me in just one thread so he had to backtrack through my other posts because he has too much fing time on his hands.

I was simply telling flash what I have found with newly mismatched systems. But by all means we can mismatch heat pumps and get all kinds of heat out of them. Higher discharge pressures and temps will give us great heat. NOT the heat we want mind you. But we will get heat. Heat of compression isn't the most efficient way to make heat last time I checked.

Why dont you go join hvacpros site and you two can spread your wealth of knowledge there. And before you jump on my back look at the real idiot here.

And lastly lets look at what disservice we are providing a customer and the industry when we spread absolute false information like this. Some people get an idea of how they think stuff works and run with it without true facts and knowledge to back it up and this is what hvacpro is spouting in my book.


and once again hf05 I cant understand half of your post or what you think your getting at. go away now.
 

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Not all evap coils have pressure ratings high enough for R410A.
York, retested all their old coils(still in production) at the higher pressures, they held, York oked them.

Carrier has tested and rated many of their older coils also. And I believe Trane has done the same.
Which ones are ok, and which ones are not. You have to check for yourselves.

At first thought. You might think higher pressure means more heat.
It doesn't. It means the coil either isn't rejecting enough heat to the inside air to have the proper pressure/saturation. Or, its restricting refrigerant flow too much. And isn't allowing enough refrigerant flow.
In either case. Less BTUs of heat are going into the house. Or you wouldn't have the higher pressure.

Generally. On a heat pump. With a mismatched indoor coil. The charge is not going to be correct for one mode or the other. You can get a way with compromising the charge. But the customer won't get the efficiency they paid for. In one or both modes.
Easily proved. By just doing a BTU test, and comparingg it against the manufacturers performance specs.

This is the reason that some units have/had charge compensators on them. The refrigerant that would have been excessive in heat mode is stored in the compensator in heat mode. And put back into the system when in cooling mode.
 

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Jerkemy.. To answer your question. if you've already changed the gas valve ! and it still does'nt work...try changing the thermocouple. And i'm not surprised u have know idea what i'm talking about. What about HVAC TALK are u a member?
 
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