Auxillary And Emergency Heat

mdshunk

Over the years, I've seen about a million and one wiring schemes for wiring the electric auxiliary heat and emergency heat in heat pump AHU's with multiple stages of electric heat. Some right, some wrong, but many just "different". One thing still sticks in my mind as a question after all these years.

In homes with multiple heat pumps and multiple AHU's, it is often common to have just one "stage" of electric heat in the smaller AHU's. What is the preferred method to hook up the low voltage leads from the stat to the AHU in that case? I have been hooking W2 and E together, and hook them both to that single stage of heat. I really don't see any other option. The bad part about that is that with certain models of thermostats, when you "backfeed" the E wire like that when the AUX heat is being called for (or when it's defrosting), the "emergency heat" light will illuminate on certain models of stats. No all stats, certainly, but a few.

Is my approach (hooking W2 and E to the same thing) the most common and textbook approach when the AHU only has one stage of heat?

wrenchman

I don't know what brands your dealing with but a W1-Y jumper is what normally brings on the compressor for heating or cooling. Normally the electric heat would be from W2 or W3, for times when there is a need for more heat. Your way the racks would run with the call for heat but what would power the compressor contactor?

HeatPro

I suppose if you work with just one brand or a few brands that are wired the same, then you can have one answer. As the reason there are many ways to wire is due to different manufacturers using different wiring ideas, there is more than one way to do it. The textbook would depend on the brand and model.

http://www.heatpro.us/service/docume...198722912.html

mdshunk

Guys, guys... we're not talking about the compressor or anything of that sort. Just the aux heat and EM heat.

How do you do it with only one stage of resistance heat? The brand plays into this question by no means. With one stage of resistance heat, W2 and E can only basicly correspond with that same stage of heat, the way I see it.

HeatPro

OK buy the premise and buy the bit.
So we are supposed to talk about a heat pump with no compressor
just aux heat, which is the emergency heat.
Chat on ...

mdshunk

Um, no.... aux heat and em heat are two different things from the controls standpoint, and assume the compressor is squared away already. The aux heat, from a controls standpoint, comes on as second stage if the compressor can't keep up. The exact staging and amount of which is sometimes controlled by outdoor stats. . Emergency, from a controls standpoint, shuts off the compressor and throws on all available backup heat without regard to the status of any outdoor stats that might exist. AUX and EM could be the same, but not necessarily.

On second thought, never mind.

HeatPro

"AUX and EM could be the same, but not necessarily."
True, if the electric strip heat that comes on for AUX isn't the same strip heat that comes on for EM. (From either the 2nd stage AUX or EM)

randomkiller

Most of the new thermostats don't have an Emergency heat position. If you only had one electric heater in a small air handler then it would be the second stage of heat from the stat (W2), if you were using a mechanical stat, then that would also be your emergency heat powered by that sub base switch (E).

__________________
"If we ever forget that we're One Nation Under God, then we will be a nation gone under." Ronald Reagan

randomkiller

That's correct.

__________________
"If we ever forget that we're One Nation Under God, then we will be a nation gone under." Ronald Reagan

randomkiller

After looking at your reference list there the only conclusion that can be drawn is that the terminal designation is brand dependent and you would need a schematic for the equipment at hand. IE: your "B" terminal has about 4 different uses. In plain terms if you don't have the specs, don't assume.

__________________
"If we ever forget that we're One Nation Under God, then we will be a nation gone under." Ronald Reagan

mdshunk

The only conclusion I was able to draw from that link was that most of it was plagerized from Scott Meenan.

HeatPro

I'm sure that readers will be fascinated with your interest in insulting anyone who provides info. It could be possible that people who've been in the trade for so many years could come across the same sources, like Honeywell and other manufacturers. Please post your original free education site link.

If I had felt that his site has all that mine did on that page, I would have posted his site.
http://toad.net/~jsmeenen/wiring.html
True, he does have half of what is on my page; but I doubt he did all the research to find that.

Yet, as we all know the "Highlander theme" is that there can ultimately be only one teacher in America and all the rest have to die, right? Bring your kids to the one school that survives.
http://www.heatpro.us/flametree/docu...894BA2514.html

mdshunk

No particular fascination, but that document was a near word-for-word copy of Scott's list that has been out since the dawn of the 'net. Even the parenthetical commentary is the same. You've been busted.

Let the readers judge for themselves:

HeatPro's Page:
http://www.heatpro.us/service/docume...198722912.html

Scott's page:
http://toad.net/~jsmeenen/wiring.html

mdshunk

You seem to have a certain way of bringing out the best in people, eh?

HeatPro

Right, I should have pasted this in my site:

http://www.white-rodgers.com/wrdhom/pdfs/instruction_sheets/37-4244E.pdf

http://www.luxproproducts.com/CrossRefwcommon.htm

I guess I'll have to eliminate my entire site because 'a NEAR word-for-word' came from the same source.

But give credit where credit is due. I guess I bring out the critical mean in you.

mdshunk

Do what you gotta do, but plagerism is plagerism. Seems pretty cut and dry to me. You could have just as easily composed that page yourself, but you nearly cut and pasted it from Scotts, and that's just not right.

mdshunk

Matter of fact, it's double not right because you're selling a product, and site content to some extent drives traffic to your site. Really uncool to use the effort of others for your enrichment. Since you have so many pages, it seems likely to me that there are going to be other examples. I took the liberty of archiving your entire site just now. It might be entertaining to see how it evolves.

HeatPro

Yes, please make a report to the public on how many of the 300 pages were copied from some other site. I'm sure SOMEBODY will have the slightest interest. Make sure you read EVERY page to check on the accuracy of the knowledge, as well. I do encourage that, as I encourage others to learn!

mdshunk

I don't really have any interest in doing that at the moment, but I can send you my PayPal address if you care to subsidize that effort.

You seem to have an awful lot of pages dedicated to flamers and character assassinators. Guess you've been well loved in other forums in the past too, eh? Surely you realize that by your age that there are certain personality types that just raise the hackles of others. Maybe you're one of them? Even the best content is for naught if the delivery isn't in a manner that is well received.

HeatPro

I think you might have heard about the "Golden Rule."
Meanwhile, you might also observe that the page about thermostats is a reference about how arguments start on the web by people who need them. http://www.heatpro.us/service/argues.htm
You've accomplished that with this thread even though the argument isn't about the subject, but something jsmeenan might have asked over the past ten years while our sites have been up. But, as I can't copyright R, G, B and the words thermostat nor Trane to exclusively describe the same items, I don't think we'll get to rights.

As I have no banner ads, click-throughs, Google ads, etc just non-profit books listings, free courses, and mostly free software made by me, the best I could do for him is to remove the reference to the terminal designations and leave that to him, Lux, Honeywell, White Rodgers. It wouldn't mean anything more to me; but it might to people seeking info.