Aux heat sequence

[Ac_man]

During aux heat on a heat pump, how many elements come on if we say its a 15kw pack in conjunction with the heat pump to raise the temp 1 degree??

[Core_d]

Ask the thermostat cause i dont know.

[mark beiser]

It depends on the equipment, controls used, and how it is all wired and

In most cases, aux heat will be all of the element,

[GT Jets]

During aux heat on a heat pump, how many elements come on if we say its a 15kw pack in conjunction with the heat pump to raise the temp 1 degree??

Your missing so much information in your question that I think the answer is William..., could be George though..

[beenthere]

As said earlier. Depends on the thermostat and how the system is wired up. Could be 5, 10 , or the full 15 KW.

[larnot]

As said earlier. Depends on the thermostat and how the system is wired up. Could be 5, 10 , or the full 15 KW.

Or, it could be 5 aux, 10 defrost and 15 emergency. More info required.

[ClimateCntlJohn]

Many heat kits will energized all banks of heat when aux is energized from stat but like the other guys said, it depends on how its set up. On alot of Trane stuff we do, I'll hook up a 15kW heat pk to energize 5kw during defrost or whenever aux is used and the other 10kW for Em Heat. Again, it depends on the equipment, look at schematic for the heat pk.

[garyed]

If I put the system in, assuming you have three 5kw elements then the answer would probably be three. If someone who likes to stage the aux heat installed it, then the answer would probably be one or two. You also have to assume that the HP along with whatever KW aux heat has enough capacity to raise the temp. 1 degree to answer the question.

[Ac_man]

So my understanding is that u can wire a couple of elements to regular heat and then wire all to emergency heat correct?? Which means 2 elements to "w2" and then all to "e" em heat,correct??

[freonjohn]

Ask the thermostat cause i dont know.

Then why did you bother to post? This used to be a nice place to gain knowledge from good decent mechanics always willing to help. Now there are just too many answers like that with absolutely nothing to be gained by anyone.
Perhaps the op doesn't fully understand the trade. With answers like that he never will.

[Ac_man]

I feel the same way freonjohn, they shouldn't be allowed on this site with smarta** answer like that

[timebuilder]

I feel the same way freonjohn, they shouldn't be allowed on this site with smarta** answer like that

Sometimes, an answer like that is a response to a post that doesn't offer sufficient information, indicating that the poster may not have done his own due diligence.

Speaking for myself, I would want to hear about the model, the serial number, how many heat sequencers there are, how the system is wired to the stat, and what the schematic indicates. Then, if there is a question, we might have an opportunity to actually give him a good answer.

[garyed]

So my understanding is that u can wire a couple of elements to regular heat and then wire all to emergency heat correct?? Which means 2 elements to "w2" and then all to "e" em heat,correct??

Most HP thermostats have a separate E terminal which serves as first stage heat if set to emergency heat but the second stage doesn't normally change & runs like usual during normal or emergency heat.

[bkmichael65]

Normally, even if you install it to come on in stages, aux heat won't come on unless it's 2-3 degrees below thermostat setpoint

[Core_d]

I too would like to be more familiar with how staging is usually played out, and ive had a few smart ellick replys to some of my posts. Right or wrong if my post bothered you i apologize.

[garyed]

I don't like to use staging for aux heat in residential. My feeling is if you need more heat than your HP can put out then give it all you got & be comfortable. I don't see any cost savings being much of an issue at all. 10kw for 5 minutes puts out as much heat as 5kw for 10 minutes & the cost is virtually the same so if you need it why not get it as fast as you can. If you didn't consider the heat pump it should save you money by not staging because the fan motor would run less. Whether its worth staging in defrost is a matter of opinion too.

[beenthere]

I don't like to use staging for aux heat in residential. My feeling is if you need more heat than your HP can put out then give it all you got & be comfortable. I don't see any cost savings being much of an issue at all. 10kw for 5 minutes puts out as much heat as 5kw for 10 minutes & the cost is virtually the same so if you need it why not get it as fast as you can. If you didn't consider the heat pump it should save you money by not staging because the fan motor would run less. Whether its worth staging in defrost is a matter of opinion too.

It does increase the heating cost doing it that way. Since your not getting as much heat from the heat pump as you would if you staged it.

[garyed]

It does increase the heating cost doing it that way. Since your not getting as much heat from the heat pump as you would if you staged it.

I don't doubt that since the COP of the pump is almost always going to be higher than 1 but I still think the savings would not be that much. Its also possible if the strips are not big enough they could run more than twice as long as ones double the size to bring the temp up to first stage heat, off setting some of the benefite of running the HP with them. I'm just guessing but I might try to do some calculations to see how the numbers really work. I would assume there are some figures out there but I haven't seen them.

[beenthere]

I don't doubt that since the COP of the pump is almost always going to be higher than 1 but I still think the savings would not be that much. Its also possible if the strips are not big enough they could run more than twice as long as ones double the size to bring the temp up to first stage heat, off setting some of the benefite of running the HP with them. I'm just guessing but I might try to do some calculations to see how the numbers really work. I would assume there are some figures out there but I haven't seen them.

The savings as the outdoor temp drop become smaller, but its still there and adds up over time.

Properly staged aux heat saves money. Improperly can cost money.

[54regcab]

On a 15KW system 10KW could be used as Aux/Emergency heat and the 5KW for defrost or use 5KW for AUX/Emergency heat and 10KW for defrost. A 10 minute "delay on make" timer could be hooked between them if 1st stage wouldn't do the job for Eheat or the air is too cool in defrost mode. If either set of heat strips call over 10 minutes it would engage the full 15KW.

The emergency heat terminal of the thermostats I've run into is energized anytime the thermostat is Eheat mode, regardless if the thermostat is calling for heat or not. Newer digital stats have done away with the E terminal, unless the thermostat has a manual switch for the heat/cool mode the E terminal is typically not there.