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Heat pump and two stage electric funace. Wiring two speed motor


Supermanu_l's Avatar
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10-10-17, 06:57 AM   #1 (permalink)  
Heat pump and two stage electric funace. Wiring two speed motor

Hi Folks ;-)...
I just moved in a new house and he heat is strange, the blower remove all the dust on the floor !!! It blows way to high !.... .....
I got a two stage electical furnace (20KW) and a heat pump....
I bought a new t-stat (honeywell RTH9580WF) and now, I'm trying to fugure how this works !.... ;-)

In the furnace manual, The furnace got two speed blower, one for heat (Bleu wire motor), and one for cooling (Orange wire motor)... (Not shown in pic, it's in the fan compartment)
But in my case, only one high speed is working, like a one stage system (Cooling or heating)

T-Stat


heater (two stage furnace) Notice the jumper on W1 and W2


This is the thing: Is there any way to connect this thing to get :

Slow blower in heat mode (Orange wire from inverser heat pump connected on W o/b of T-stat) To get heat from heat pump
Slow blower in heat mode (white wire (heat) on auxilary heat T-stat (W2) to give boost if heat pump rushes
High blower in emergency heat mode (where do I connect this ?) It's verry cold in Canada sometimes !
Slow blower in cooling mode (Y on Y) because in summer, it's hot too ;-)

Of course,
G to G (blower wire)
C to C (Common)
R to R (hot 24v)

in the circulating air cycle, the air flow in duct hits the cooling/heating serpentin, then goes to blower, then goes to heat resistor, to get out by duct exaust..... then goes in the house and get back in return duct and start over.... and over.... and over. I know it's important to not blowing hot air from heat resistor directly to the serpentin, in my case, it's OK ;-) that mean I can heat by heat pump AND 1st stage at same time ;-)....

Thanks for you suggestions ;-)


Last edited by Supermanu_l; 10-10-17 at 07:56 AM. Reason: knoledge
 
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MO

10-10-17, 08:37 AM   #2 (permalink)  
That's not considered a 2 stage furnace, heat pump is the 1 stage and the furnace is the back up heat. Can you post a pic of the old stat withj the wires connected ?

 
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10-10-17, 10:26 AM   #3 (permalink)  
Hi skaggsje,
This is the old t-stat
Name:  t1.jpg
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I read a lot and I my understanding is: W1 and W2 are those two stages in the furnace... Maybe i'm wrong....


Last edited by PJmax; 10-10-17 at 10:39 AM. Reason: resized pic from link
 
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10-10-17, 10:42 AM   #4 (permalink)  
A two stage electric furnace would have two stages of heat but the fan speed doesn't necessarily change too.

You would need a three stage heat stat but the problem is the stats don't work that way in heat pump mode.


~ Pete ~

 
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10-10-17, 11:06 AM   #5 (permalink)  
Hi Pete
You right, but the thing is there is two speed on that furnace.... (FEM20-M2301CM-B)
One speed for Cooling, and one speed for heating.... (those two speed can ben the same, depending on the connection I made in the blower compartment...)
but How does the furnace knows the difference ? Is it because the furnace see a 24V on "Y" to say: "Yeah, that's the cool mode, let give cool mode speed"
And when i'm on heat mode, the furnace doesn't see the 24V on "Y" so it say "Yeah, the cold body need to be warmed, let give him the warm/hot speed"...

 
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10-10-17, 11:20 AM   #6 (permalink)  
It's written in furnace manual than when two stage is used, switch the "Manual switch" to High --"Also, this switch must remain in the HI position when a 2- stage or outdoor thermostat is used to control the electric elements of the second stage--"

 
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10-10-17, 12:30 PM   #7 (permalink)  
Seeing a signal on Y will close the manual fan control relay and use the pre-selected speed.... in this case cool for A/C. In normal electric heating mode.... the sequencer sets the fan speed which is usually lower.


~ Pete ~

 
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10-10-17, 01:01 PM   #8 (permalink)  
ok, that mind I can't use this option "Y" to play with motor speed in "W1" cycle...

I should add a relay driven by W1 to close the high speed fan circuit and open the low speed fan circuit....

the reason is when the fan blows to high speed (Actualy normal mode), it's crazy speed !.... lol... It look like a jet in my bedroom ! (Just above the furnace) and it wake me up !


What I have to do:
Connect orange to W o/b
connect white to W2 Aux and to a coil relay and switch to the high speed circuit when activated.... and in low speed circuit regular.... that should works.... right ?

 
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10-10-17, 03:59 PM   #9 (permalink)  
Not really sure what you are doing. Keep in mind that you should be following the heat pump designations on the stat. That means using the labels at the bottom of your picture. You'll notice there is no W1 or W2 there.

W1 IS O/B in heatpump mode. O/B is for reversing valve for stage 1 heating.
W2 is AUX heat in heat pump mode.


~ Pete ~

 
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10-11-17, 05:30 AM   #10 (permalink)  
Yes Pete, I discover that o/b is for W1 and Aux /E is for W2;-)....

ok, let say I need two speed for heatting.... and one speed for cooling (Slow)....
The reason I need two speed is the noise..... I do not want to ear a jet plane each time the temps need to be maintain.... When I increase 2 or 3 degres, no probleme, I'm asking the systeme so I don't care but in the night, it's a problem....

For testing, if I remove the Y wire from stat, it's like the out temps is to cold (-15C) to start the heat pump (Compressor), so only the furnace will start in W1 mode at High speed (no more Y).... Right ?

 
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10-11-17, 08:20 AM   #11 (permalink)  
You don't need a thermostat, you need duct repairs. Your unit is too big, or the ducts are too small, or a combination of both is happening. You may need high speed to move enough air to satisfy the heat pump and electric heat strips.
Approximately how much airflow do you have right now in CFM?
How much airflow does your system require?
Is the noise from a return or supply duct?
The thermostat is not controlling fan speed. The air handler is based on the call it's getting.

 
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10-12-17, 08:03 AM   #12 (permalink)  
ok, the air duct in my bedroom is 8 ft long and 5 inch diameter.... solid round duct, well taped and sealed
I checked out all supply vents are wide open and all blow enought air....

Presently, I set the blower to med/low speed and it works perfectly.... rise the temp from 19C to 22C in less than 10 min .... and not so much noise in the room.... ;-)

I know the thermostat do not control the fan speed, but the fan speed is controled by signal from Y.... ;-)... and the Y signal come from thermostat.... So when the outside temps will below the critical heatpump temp, the Y terminal will not fiered so the blower will go to the "heat mode" speed.... right ?

The furnace is design to work at med/low or med/hi speed depending on demand/size of the house.... so It sould be OK ;-)

 
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10-12-17, 08:26 AM   #13 (permalink)  
So you have a duct capable of moving 60 CFM at around .05" static. What is your static in heat mode?
It sounds like the entire system is oversized if it's bringing the temp up that quickly.
Everything else there, your a bit misunderstood in how the unit works.
Airflow is critical. You cannot just lower it without checking the system for proper operation.
Fan speed is not set by the size of the house.

 
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10-12-17, 11:03 AM   #14 (permalink)  
I don't know what "static" calculation is.... :-(
I do know air flow is important to not baking heat resistors.... but there is a diference between the air flow, and the jet flow..... maybe the motor was changed by a bigger one.... Like I said, i'm just arriving in that house.... ;-) I don't know the story of the heating system...
I know the noise is comming from the vent supply in the master bedroon, and the room next to, both are just above the furnace, and firsts ducts exiting the master duct, 5 feet away from the blower and 5 feet long of round duct 5 inch round.... All ducts are visually in good condition.... Maybe that is the trouble, way to close to the blower.... ;-)
Thoses rooms are not warmer than others....

 
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10-12-17, 11:20 AM   #15 (permalink)  
ok, new concern.... lol...
in heat mode.... the T-stat goes:
C and R for power
Y = 24V
G = 24V
o/b = 24V
aux = 0

after 5 min, the t-stat shows: "Aux heat mode"
is that means:
Y = 0
G = 0 or 24V ?
o/b = 0
aux = 24V
or it just fire "aux" added to the heat mode ?
Thanks ;-)


Last edited by Supermanu_l; 10-12-17 at 11:23 AM. Reason: typo
 
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10-12-17, 11:40 AM   #16 (permalink)  
Auxiliary heat comes on during defrost, during emergency heat mode and during times where the thermostat falls from its intended setpoint. How much that fall is depends on the specific thermostat.

 
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