Help rewiring control system for multistage heat pump

6731 Views 12 Replies 4 Participants Last post by hvactech126, Dec 11, 2012

ink

Discussion Starter · Dec 9, 2012

I recently had a new heat pump installed in place of an old A/C system. It's a multi-stage; Amana ASZ140361

Link to product description

Side note.. this IS a multi-stage unit, right!? That brochure is making me wonder.

It's paired with a Goodman variable speed air handler AVPTC313714.

Link to Product description

Lastly, I bought a Nest thermostat to control it all with.

First day of operation, it was clear the variable blower speed was not working. Pulled the cover of the Nest, and saw this:

Well there aren't enough wires there for variable speed operation to work. The installer reused my old thermostat wire. So I just ran a new one now and went to wire it into the air handler.

The Y1 and Y2 wires (black and yellow, respectively) were wire-nutted together with the Y lead in my old 5-strand thermostat wire and the Yellow lead in the control wire down to the heat pump. For the new 18/7 wire, I wired Y1 to Yellow, and Y2 to Brown. For the control wire to the heat pump, I referenced a diagram I found here, which says that, yes, I should have a first and second stage (Y1,Y2) connected to the heat pump.

Then I went outside and pulled the cover off of the unit and noticed that there are two poles, both labeled "Y", and only one has a lead to the control wire going up to the air handler. But the schematic on the inside cover seems to indicate these two are combined?

My plan is to run a lead from that second Y to the brown lead in the control wire, which will be wire-nutted to the brown lead in the air handler going to both Y2 and the thermostat.

So, the two questions are:
1. Is this a multistage heatpump, because, dang it, that's what I bought.
2. Is my wiring plan correct?

Thanks!

See less See more

Save

1 - 13 of 13 Posts

Technow

· #2 · Dec 9, 2012 (Edited)

Single stage heatpump. i am not up on Goodman/Amana products because I quit selling them years ago.

The thermostat wiring is definately wrong for a heatpump

Save

ink

Discussion Starter · #3 · Dec 10, 2012

Uuuugh. The salesman at the Goodman Mfctr distro center swore to me this was 2 stage. Now I've got to figure out how to return and swap this thing.

For the wiring as is, though. I must've done something wrong because the on board fuse is blown.

Save

hvactech126

· #4 · Dec 10, 2012

agreed..... single stage HP but it could be a multistage system if you have heat strips installed for the air handler. GET RID OF THE NEST.... It is a poor choice for a heat pump thermostat, IMO.

Save

beenthere

· #5 · Dec 10, 2012

Single stage heat pump. You probably have aux strip heaters, that he is counting as second stage heat.

Multistage is 2 stages of heat pump heat. Weather or not you have aux heat is not included.

You would want the ASZC 16 or 18 to have a 2 stage heat pump.

Save

ink

Discussion Starter · #6 · Dec 10, 2012

beenthere said:
Single stage heat pump. You probably have aux strip heaters, that he is counting as second stage heat.

Multistage is 2 stages of heat pump heat. Weather or not you have aux heat is not included.

You would want the ASZC 16 or 18 to have a 2 stage heat pump.

I don't have aux strips... I've got radiator heat in the house (oil-fired boiler), so that's my "aux heat", now. Too expensive to run as primary. Too bad, too, cuz it's way better heat than the heat pump. At some point I have to figure out how to run the zone valve control to the aux terminals of the thermostat correctly. This 2nd version of the Nest supports that, but I haven't given it much thought, yet.

I just got off the phone w/ the Goodman dealer. The guy I bought it from is confused, because he thinks that the "two speed fan" on the heat pump means that it's a 2-stage compressor. I'm trying to explain to him the difference. Come on, guy, this is YOUR product and I'm having to tell you this? No wonder I got the wrong one.

Save

ink

Discussion Starter · #7 · Dec 10, 2012

Talked to the more technically proficient guy at the distro center. He tried to sell me on using the dip switches to adjust the system, but of course, that only works to permanently lower the CFM of the blower, not somehow magically enable variable speed capability on a single-stage heat pump.

Since it's been installed, I can't return it, so I'm stuck calling consumer affairs. Another option would be to convince them to give me a really good price on the ASZC16 unit and use the ASZ14 one for the main floor of the house. I'm not ready to install the new air handler for the main floor, though, so I'd have to store the heat pump for a year before installing.

I'm convinced I could do the main floor install myself with your guy's help and just have someone come out to run the line set and charge the system.

Save

beenthere

· #8 · Dec 10, 2012

Well, when you get the ASZC16. its a communicating unit, so it will match to the air handler. And you might want to consider getting the communicating thermostat for it, which allows much more control over the blower then the Nest can ever do.

Save

ink

Discussion Starter · #9 · Dec 10, 2012

beenthere said:
Well, when you get the ASZC16. its a communicating unit, so it will match to the air handler. And you might want to consider getting the communicating thermostat for it, which allows much more control over the blower then the Nest can ever do.

You know, I gave that some thought. Those comfortNet therms are $300+ and I wasn't finding anything to justify that expense. What is your experience with them?

Save

hvactech126

· #10 · Dec 10, 2012

You find $250 is acceptable for a poor thermostat (nest)? A communicating stat is always worth the money if the system is designed for it. The nest is not designed specifically for your system.

Save

beenthere

· #11 · Dec 10, 2012

They give you much better control over blower CFM. Temp control not really better then any other high end stat. Hard to wire wrong(only 4 wires at stat).

Save

ink

Discussion Starter · #12 · Dec 11, 2012

hvactech126 said:
You find $250 is acceptable for a poor thermostat (nest)? A communicating stat is always worth the money if the system is designed for it. The nest is not designed specifically for your system.

Why don't you like the Nest? You are the first person I've heard that doesn't like it, with the exception of some people with specific needs like remote temp sensors, multiple peripherals (dehumud, 3rd stage heat), etc.

Save

hvactech126

· #13 · Dec 11, 2012

First, for a HP system, you are best to leave the temp at one setting. The nest is a way over priced yoyo that you put on the wall, IMO. Why would anyone spend $250 on a thermostat that is not even going to do a good job of keeping you comfortable? Do you really want a computer program deciding what temp you want your home at? If you want a wifi thermostat you can get one for much less. Nest has a lot of problems from what I see on many forums. There is not very good support for their product. Many of their support staff don't even seem to know everything that the stat does or does not do. For the kind of money they are asking for one of these stats they should have done much more beta testing and had their product ready for field usage. They claim 99% of installations don't need a C connection. This does not seem to be the case from what is being broadcast on forums. For heat pumps they had a major glitch where after every call for cooling the reversing valve would lose it's signal and cause loud banging in the outdoor unit caused by the RV switching. This was very alarming to homeowners. I just can't justify spending that kind of money on a thermostat that can't control most every system properly. Nest has had many many problems charging their batteries. Batteries should not be used for any type of wifi stat. Wifi radios use way too much power to try to run them off a battery. I'm just rambling here, but I can tell you that I really don't like the NEST. I just can't wrap my head around the hype.

See less See more

Save

1 - 13 of 13 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.

Top Contributors this Month