Go Back  DoItYourself.com Community Forums > Heating, Cooling, Air Conditioning, Ventilation and T-Stat Controls > Heat Pumps and Electric Home Heating
Reload this Page >

4 stage heat 2 stage cool with hot water coil/electric defrost(3rd-4th stage)

4 stage heat 2 stage cool with hot water coil/electric defrost(3rd-4th stage)


  #1  
Old 06-03-16, 10:31 AM
J
Member
Thread Starter
Join Date: Jun 2016
Location: USA
Posts: 47
Received 0 Votes on 0 Posts
4 stage heat 2 stage cool with hot water coil/electric defrost(3rd-4th stage)

I do have HVAC background, but I have been out of the field a long time due to injury. Plus I did not service many heat pumps where I was from. Things have changed a lot with terminology and terminal designations it seems...

I have Airtemp 16 seer 2 stage heat pump(67% or 100% compressor) with 2 speed cond fan and variable blower.
Model- VT4BF-036KA (Cond)
Model- B6VMAX36K-B

Original system had isolation relay which completed circuit for circulator pump, but they also used that relay to energize the fan(pulling 24v from the R/Rc) and during defrost(W2 from condenser).

New setup has an electric strip heat and hot hot water coil. The electric is for stage 4 or if boiler fails, the defrost heat source.

I believe I need a 4 stage heat/2 stage cool tstat(heat pump)

My wires for Tstat(Do not have 2 stage for heat pump):
R - jumped to Rc - 24v
C - Common
O - Reversing Valve
G - Fan
Y1 - Stage 1 heat/cool
Y2 - Stage 2 heat/cool
W2 - Stage 3 heat(hot water coil)
W3 - Stage 4 heat(Electric strip)
L - Monitor

Air handler terminals:
R - 24v
C - Commom
O - Reversing valve
G - Fan
Y1 - Stage 1 heat
Y/Y2 - Stage 2 heat/cool
W1 - Stage 3 heat(hot water coil)
W2 - Stage 4 heat(Electric strip)
L - Monitor

Condenser terminals:
R - 24V
C - Common
O - Reversing valve
Y - Stage 1 heat/cool
Y2 - Stage 2 heat/cool
W2 out - Defrost
L - Monitor

I do not have outdoor stat hooked up...

Orignial tstat(Honeywell 7600?)had both Aux and E hooked up. Is Aux or E powered when in "Emergency heat"? I believe they had E as emergency and Aux as defrost(which was also E, but not jumped at tstat. It was a jumbled mess of wires from original installer....

I need recomendation for Tstat.

Needs 4 stages of heat 2 cool in Heat pump mode.

Then after Tstat recommendation, perhaps wiring help...

We have it running in Single stage now with existing tstat with relay removed and no strip heat.

Just basic heat pump, R, C, O, G, Y1,L

Tstat will do 2 stage cooling, but only in AC only. So I would need to energize the O manually for Y1 and Y2 if I want both stages...hence the need for new stat.

I want to set it up as follows:

Y1 and Y2 as 2nd stage heat/cool
W2 and W3 and 3rd and 4th stage heat

Hot water coil 3rd stage and defrost
Electric strip as 4th stage

I would also like a manual switchover(if needed) to select my defrost/emergency source(if hot water fails).

I guess my confusion is how tstat will handle emercency heat mode in a 4 stage heat stat. Will it call for W2 and W3 or just one?

I have isolation relay for water coil, which they also used to energize the fan...is this needed? Seemed to be uneeded, but perhaps the old tstat required it?? Current stat(I replaced 7 years ago) was fully functional, so I never really looked into what they were doing. Do I need to manually energize fan for emergency heat/defrost? Does not seem to be needed.

So first I need tstat recommendation...

Would like wifi capable if possible.

Thanks in advance and sorry for any errors.

JJ
 
  #2  
Old 06-03-16, 11:32 AM
airman.1994's Avatar
Member
Join Date: Dec 2005
Location: VA
Posts: 5,795
Received 8 Votes on 8 Posts
Honeywell pro 9000 would be the go to stat
 
  #3  
Old 06-03-16, 02:09 PM
J
Member
Thread Starter
Join Date: Jun 2016
Location: USA
Posts: 47
Received 0 Votes on 0 Posts
Thanks....

I am still a bit confused, but I also had a few typos so maybe I wasn't clear.

Is the 9000 3 or 4 stage in heat pump mode?
My compressor is 2 stage, Y1/Y2.
Then I have hot water coil set as Stage 3 and Defrost.
I also have electric strip heat that would act as stage 4, but also as a backup for stage 3/defrost if boiler fails...so technically I need 4 heat I think.

I would like hot water coil and electric to work independantly. Then a manual switch for flipping Stage 3/4.

Model: THX9421R5021WW

Seems to have 4 heat, 2 cool.

I am missing something with the 9000? Its says 3 stage heat?

Thanks
 
  #4  
Old 06-03-16, 04:18 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,843
Received 1,477 Votes on 1,365 Posts
Three stages needed....
1- heat pump
2- hydronic
3 - electric

Stage 3 could also be called emergency heat.

I have to look further into the programming but I think you're pushing the limit of a stat. You are asking it to make many changes. Now you're also incorporating multi fuel.

My partner, Houston, may know the answers off the top of hid head.
 
  #5  
Old 06-03-16, 07:06 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
Is the hot water coil radiant heat or forced air?

I see 4 stages of heat in that model number and in the diagram.

TH8110 = 1 heat / 1 cool

TH5220 = 2 heat / 2 cool

TH8320 = 3 heat / 2 cool

THX9421 = 4 heat / 2 cool

Have you seen this diagram in the thermostat section?

 
  #6  
Old 06-04-16, 07:28 AM
J
Member
Thread Starter
Join Date: Jun 2016
Location: USA
Posts: 47
Received 0 Votes on 0 Posts
Thank you for the schematic...

Just so we are on same page...

Y1-Stage 1 compressor(heat/cool)
Y2-Stage 2 compressor(heat/cool)
Aux1-Stage 3 heat(water or electric)
Aux2-Stage 4 heat(electric or hot water)

It is a hot water coil in ductwork with a circulator, activated by isolation relay, which also activates the fan via the relay(went to time delay for fan in old unit. No aquastat.

On my literature, it shows W2(from compressor going to W1(Aux1). Which would activate Aux 1(+ fan) during defrost via isloation relay.

That schematic seems to have what I need(Aux 2). Would I need to manually activate the fan as with Aux 1?

Does the new unit control the fan in Aux 1 and 2? Do I need to use the isolation relay to activate the fan as well as well as the circulator, or is there a setting in tstat to activate the fan when Aux 1 or 2 is calling and have the isolation for the circulator only?

Other option is to use 3 stage and have manual switchover for electric/hot water, but I would prefer to have electric as last line of defense. I leave house for extended periods some times.

It is also a log home, so add ons like humidty controls, wireless sensors, etc are very handy. No where to run wires in this house easily...The schematic above seems to show the tstat I need.

Thanks.
 

Last edited by JJinPA; 06-04-16 at 07:28 AM. Reason: typo
  #7  
Old 06-04-16, 08:52 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
I drew that for someone that doesn't have forced air hot water heating. The thermostat can bring in the fan for Aux heat.

That is the older Honeywell Prestige IAQ. The new model has a smaller border around the screen and two additional wired sensor inputs.

Since this stat is in the Honeywell Redlink line wireless sensors are also an option.
 
  #8  
Old 06-04-16, 10:00 AM
J
Member
Thread Starter
Join Date: Jun 2016
Location: USA
Posts: 47
Received 0 Votes on 0 Posts
Thanks...

I believe original Tstat when I bought the house could not control fan, hence they had the isolation relay controlling fan in heat/defrost. When I wired in new stat, I don't think that fan control was needed, but worked as wired anyway...So I never really tried to decipher the mess they left.

But when we ripped out the old and was taking note of wiring, I noted what they were doing.

So I can just use the isolation relay for boiler(circulator) only, with Tstat handling the fan, correct?

Thanks for the all the help. It has been a long time since being in the field. Now I am remembering why I prefered commercial rooftops to split res systems....

At least I am the homeowner looking over my own shoulder
 
  #9  
Old 06-04-16, 11:18 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
MagicAire Air Handler

Yes, the Prestige IAQ can energize the fan circuit with Aux heat.

I usually install this control on Magic Aire chill water air handlers.

I installed these two units last week...



 

Last edited by Houston204; 08-07-18 at 07:28 AM.
  #10  
Old 06-04-16, 05:35 PM
J
Member
Thread Starter
Join Date: Jun 2016
Location: USA
Posts: 47
Received 0 Votes on 0 Posts
Nice and neat

It looks like if I want 4 stage, I need to go the IQ route.

In meantime, my current stat only does 2 stage cooling in non heat pump mode. Can I use relay to activate the reversing valve temporarily(using Y1 and Y2 to activate relay) so I have 2 stages of cooling, or would that cause issues with the boards?

So far 1st stage seems to keep up. Just makes it a little drier...
 
  #11  
Old 06-04-16, 07:42 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
Thanks.

The compressor would not be energized in heat mode.

If this is only temporary until the new stat comes in you can just connect R to O outside.
 
  #12  
Old 06-08-16, 07:59 AM
J
Member
Thread Starter
Join Date: Jun 2016
Location: USA
Posts: 47
Received 0 Votes on 0 Posts
Any recommendations on whole house humidifiers?

My Dad is old school and likes Aprilaire stuff and I never had issues with them, but being out of the field a while, I have not seen the honeywell systems and how they hold up.

I would love steam, but I think my well water makes that an issue, unless I install an RO system. I currently have two filters. One sediment followed by a finer carbon filter.

The honeywells seem to be highly compatible with both the air handler and tstat.

Would you recommend the Aprilaire or the Honeywell systems? Or perhaps another one?

Waiting on tstat...Will update with pics once I get back home to install.

I had question with defrost cycle too. My hot water coil is just controlled by the relay/circulator. Basically the coil is as hot as the boiler, no aquastat. Will this cause an issue with defrost? The coil is literally 6ft from the boiler..maybe 12ft total in the loop. Would I be better off using the electric strip heater(built into airhandler) for defrost or stay with the hot water?

With the new stat, if I have outdoor humidity/temp sensor hooked up, will that work to cut off heat pump below x temp? Or do I need to add an outdoor stat to lock it out?

Thanks again.
 
  #13  
Old 06-08-16, 04:13 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,843
Received 1,477 Votes on 1,365 Posts
The coil in the air handler doesn't affect the defrosting sequence. It's job is to temper the returning indoor air so that you aren't getting frigid air from the ducts during defrost.

Aprilaire makes good units. Although the steam type are high output and high efficiency they are somewhat high in service and expensive to repair.

The type with the water flowing over the pad is good for washing away minerals.
 
  #14  
Old 06-08-16, 05:46 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
I have only worked with Aprilaire and Carrier humidifiers. It is important to know if your humidifier has it's one transformer when connection it to the humidifier.

Since it is just 2 or 3 wires any humidifier can be controlled by your EIM.

An electric heat strip might be quicker which would result in better comfort when defrost initiates but the hot water coil is already in place. Would the hot water coil be able to give you heat in a couple of minutes with your setup?

I work with chill water and hot water coils almost every day but the high rises are setup differently than residential applications.

Yes you can configure lockouts with the wireless outdoor sensor without the need for an additional outdoor thermostat.
 
  #15  
Old 06-09-16, 03:14 PM
J
Member
Thread Starter
Join Date: Jun 2016
Location: USA
Posts: 47
Received 0 Votes on 0 Posts
Thanks again...

Hot water is fast...So I will leave hot water as defrost/Stage 3 and keep electric for stage 4.

The strip kit was cheap for the unit, so I like the peace of mind, knowing if the boiler craps out over winter I have backup defrost/heat.

Just waiting on a few quotes for the stat...Trying to get the wifi/etc as a package.

So far $270 is best price I can find, base system + wifi...

Itching to put this in....Looks like nice setup.
 
  #16  
Old 06-11-16, 06:38 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
That is a good price. Looks like it is $311 on Amazon for the stat, EIM,Gateway,duct sensors and adding the outdoor sensor.



https://www.amazon.com/Honeywell-YTH...eywell+redlink

https://www.amazon.com/Honeywell-C70...AAWXQWGRPJBTPM
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: