heat pump/air handler question

[powerg]

Hi,

I have a question regarding heating/cooling using a heat pump system.

First, my system conist of the following.
Lennox CBX32MV air handler
Lennox HPX15-4 ton heat pump
Lennox HC-PMAC20 air cleaner
Lennox Digial Touch screen t-stat
Lennox Harmony III Zoning System

Second, my house has ducts installed for 2 zones (up and down) over 3100 sf.

My questions.
1. I set the t-stat on both levels to 68 degrees. Current temp is 72. How long should it take to cool to the desired temp? I noticed the ouside unit would only stay on for a few minutes then the fan would blow without any cooling then the outside unit would come back on again. The outside unit does not stay on continuously until the desired temp is reached. Is this normal? Wounld'nt this take a lot longer to cool down house??

2. The air that is coming out from all the registers is very low. My heating contractor said that is how a heat pump system works. A lot slower movement of air compared to a oil furnance. This is correct?

thanks.

[The Penguin]

I suggest you find another quality contractor to go over your system locally.

generally the air flow should be greater for a heat pump over an oil furnace (but not always)

if your zones are calling for cooling then the outdoor compressor should stay
on

is the compressor shutting off or just the fan?

too many variables - get another contractor in to take a look

[powerg]

thanks for the response.

both the compressor and fan stays on for a few mininutes...then the compressor would stop but the fan would continue...then later (5-10 mins later) the compressor would come back on again...goes on as a cycle. the t-stat is set to circ and cool. not sure why the compressor would come on and off before the disired temp is reached. thanks.

[totaleclipse]

I agree with Penguin, you need to find a new contractor. The system you have is a very nice set up, and with anything nice, it can be messed up pretty easy in the hands of someone that doesnt know/understand the equipment.

The zone board has a discharge air sensor that will cycle the outdoor unit off and on if the discharge temp is to low, and with you saying that the air is barely blowing, this makes sense, although hard to say for sure without looking at the equipment.

You need to find a Lennox dealer to look at the system and make sure it is set up correctly. If you need help finding someone, you can go to there web site at www.lennox.com (http://www.lennox.com), click on the residental section, then look at the upper right corner for find a dealer. Again, this is not your everyday run of the mill equipment, you need someone that knows the equipment to work on it.

[t527ed]

sounds like outdoor unit may be cycling on plenum thermostat.
could be an airflow problem.

[powerg]

Thanks for the replies.

There is air coming from the ducts but a less than what am I use to (my parents place has a gas furnace and it has more air coming out of that system).

When the installer turned on the system I mentioned about the low air flow and he told that's how it's suppose to be.

So when I set the t-stat lower, does the compressor suppose to stay on until the desired temp is reached or cycle on an off?

[powerg]

I should say one more thing...the outside unit fan is cycling on and off...I am not sure if the compressor is doing the same thing. When the fan is off, does it mean the compressor is off as well? I just notice the outside unit is quiet when there is still a heating or cooling demand.

[powerg]

Hi all,

I just talked to the heat pump contractor about my problem. He said we are missing a weight for the bypass damper and currently the damper is set open using a vise grip. We lost the weight during the renovations. He told me to call the ducting contractor to balance the system. Right now I the outside unit is short cycling.

Also, I noticed that our Lennox programmable t-stat (Model number 8320) is missing AUTO and EM.HEAT on the System screen. I looked at the manual for it and it's suppose to have these two switch on both our t-stats. Anyone know what's the problem. Thanks a lot!

[techace79]

get another guy out there before its to late. sorry to bust your cont. up but i would tell anybody that. if just your comp. is cycleing on/off and the "motor on top" is continuossly running then you have a problem that u need someone else to look at.

[dash]

Hi all,

I just talked to the heat pump contractor about my problem. He said we are missing a weight for the bypass damper and currently the damper is set open using a vise grip. We lost the weight during the renovations. He told me to call the ducting contractor to balance the system. Right now I the outside unit is short cycling.

Also, I noticed that our Lennox programmable t-stat (Model number 8320) is missing AUTO and EM.HEAT on the System screen. I looked at the manual for it and it's suppose to have these two switch on both our t-stats. Anyone know what's the problem. Thanks a lot!



Exactly what I would have thought,though it could be other things.


The bypass is likely too large as well.This may be where that missing air flow is going,which then causes the outdoor unit to cycle off due to low leaving air temperature from the coil,in cooling.

Advise your tech,to size the bypass damper and duct at 1500 feet per minute minimum.

[totaleclipse]

Also, I noticed that our Lennox programmable t-stat (Model number 8320) is missing AUTO and EM.HEAT on the System screen. I looked at the manual for it and it's suppose to have these two switch on both our t-stats. Anyone know what's the problem. Thanks a lot!

With the Harmony 3 the stats are set up as 1 heat/1 cool conventional, regardless of what equipment it is controlling, thus you will not have the em. heat option on the stat. As for Auto, there is an option in the installers set up that you can turn on, factory default is no auto.

[powerg]

Thanks for the reply.

So the t-stat has AUTO and EM.HEAT as an swtich but because I have the Harmony 3 installed as well, the t-stat does not show these two switches?

I can only turn on EM.HEAT from the Harmony 3 only?

How got I get the AUTO? I can't find that code from the Manual.

Thanks.

[t527ed]

lennox v drive system with harmony control package should NOT have any bypass damper installed.:eek: :eek:

better get someone in there that knows what they're doing.:confused: :confused:

[totaleclipse]

Thanks for the reply.

So the t-stat has AUTO and EM.HEAT as an swtich but because I have the Harmony 3 installed as well, the t-stat does not show these two switches?

I can only turn on EM.HEAT from the Harmony 3 only?

How got I get the AUTO? I can't find that code from the Manual.

Thanks.
Em. heat can only be turned on from the Harmony 3, but this is something that you likely/hopefully will never have to touch.

The Auto function is option number 300, set to 1. When using the auto mode, I recommend a deadband (difference between heat setting and cool setting) of no less than 4*, factory defaut is 3*. This is option 310, the setting is the deadband in degrees.

And I agree with T527 on the vsb and bypass thing.

[powerg]

Thanks for the reply.

I hope I explained it well. A bypass damper is the sames a barometric damper right with a counter weight? I tested the system today in both heating and cooling mode. Heating mode seems okay, the heat pump stayed. In cooling mode, it was a bit strange. I stopped one t-stat and restarted in min later, the t-stat said waiting while the other one was still in cooling mode but the Harmony turned off the cooling. I started cooling a few mins later....is this normal?

[powerg]

I don't need a bypass damper? Does the Harmony 3 control pressure? I just found out that I need to get a whole new bypass damper to get the missing counter weight!

The t-stat does not have humidistat. Should I have this option with a v-speed blower?