Bedrooms not heating but cooling fine???

[adamwhatley]

Hello gentleman,

I have a strange problem with my new Trane hvac system. My system cools my house fine during the summer but does not heat my bedrooms up during the summer. This is puzzling to me as I know it takes more cfm to cool a room then to heat it up. Any ideas??? My system information listed below.

Trane Heat Pump: Model # 4TWR5030E1000a
Trane Hyperion Air Handler: Model # TAM7A0C36H31SAA
Heat Pack: 10kw
T-stat: TCONT803

My house has R-38 in the attic that was added after the installion of the new system. My house is 1400 square foot heated.

[skippedover]

Are you really doing both heating and cooling in summer or is that a typo? Just asking. :whistle:

Are you sure the HP is working properly? I mean, could it be low on refrigerant? How do things heat if you put the system into "Emergency" mode? Perhaps the heat strips aren't wired correctly or are not properly supplementing the HP. Not knowing OAT conditions and whole lot of additional pressure and temperature readings, it's nearly impossible to provide useful information on your problem. Sorry.

[adamwhatley]

Yes that was a typo. What I meant was system worked fine this pass summer. This is my 1st time with heat pump in the home. Refrigerant was checked along with wiring of the system and everything per the tech is working fine!

[udarrell]

Location: West Monroe, LA
Is that Los Angeles?

[adamwhatley]

it is Monroe, LA. Louisiana

[jimj]

Hello gentleman,

This is puzzling to me as I know it takes more cfm to cool a room then to heat it up. Any ideas???
My house has R-38 in the attic that was added after the installion of the new system. My house is 1400 square foot heated.

Not always the case. You can have a Northern facing room or rooms with little internal load and need more heating cfm that cooling cfm. If a proper room x room load is done you will have the answer to you question!:grin2:

[motoguy128]

Yup, north facing rooms can be a problem. Smaller cooling loads in summer and higher heating loads in winter. Similar to the problem you have with a 2 story home.

[tipsrfine]

I'm thinking a ranch home and the bedrooms are on the north side of the building?

[udarrell]

I thought it might be Louisiana.

In the summer the wind is normally from the south, in winter it is normally in the north or NW. If there is a strong north wind & there is fairly high air infiltration that also alters the heating equation by also reducing the airflow to those rooms.

When we talk about External Static Pressure (ESP) the airflow varies as to the pressure in the rooms being served. Therefore with a real strong north wind, the rooms on the southern portion of the home would have lower room pressures & more related air flow & north rooms higher pressure & less air flow.

Of course in the winter, there is also a loss of heat due to exfiltration.

Additionally, perhaps there is insufficient Air Return for those north rooms.(?)

Using balancing dampers at the branch take-offs might also be helpful.

The Shreveport/Monroe Louisiana winter design is only 20-F.

What sq.footage is, or are, the rooms not receiving adequate heating?
What size are the branch duct runs?

If we use 70-F indoors winter design of 50-F delta-T & the lowest level of weatherization on a 120-sf >(? sf of cold) north room(s).

Oh, it's a 2.5-Ton heat pump, not a gas furnace!
That calls for larger duct runs & more air flow, than a gas furnace.

What's the temp-rise over the indoor temp > at the outdoor conditions when there is insufficient heating of those north rooms?

We might be able to provide a rough estimate of the Btuh need compared to what is being delivered...

However, a Home Energy Efficiency Audit with retro-work & a heat-loss calc with a manual D duct evaluation would help resolve the problem.

[udarrell]

Hello gentleman,

I have a strange problem with my new Trane hvac system. My system cools my house fine during the summer but does not heat my bedrooms up during the [winter]. This is puzzling to me as I know it takes more cfm to cool a room then to heat it up. Any ideas? My system information listed below.

Trane Heat Pump: Model # 4TWR5030E1000a
Trane Hyperion Air Handler: Model # TAM7A0C36H31SAA
Heat Pack: 10kw
T-stat: TCONT803

My house has R-38 in the attic that was added after the installation of the new system. My house is 1400 square foot heated.

I didn't look up the specs on your heat pump, so just a rough estimate below.
Heating mode; Goodman 2.5-Ton heat pump at outdoor winter design 20-F; 70-F indoor dry bulb; nominal CFM; only 19,200-Btuh; temp-rise-split 17-F.

Shreveport summer design 96-F dry bulb; 76-F wet bulb or, 40% relative humidity.

Cooling mode ACCA (TVA) conditions; 95-F outdoors; indoors, 1050-cfm; 75-F.; 63-WB or, 50% RH; 26,700-Btuh; 20-F temp-drop-split.

After a heat-loss manual J, & manual D, are performed you'll know what needs to be done.

How does it heat those rooms using the 10-KW Heat Pack?

[adamwhatley]

Thanks guys all your ideas make sense. With regard to the return air, I have one 20x25 With a 14 or 16 inch flex duct going to my air handler in the attic. It is located in center of my home. The company that installed my system recommended other returns in all the bedrooms but since I was not having problems keeping the rooms cold during the summer did not see a need at that time.

So what you are saying is that now that we are into the winter months this might be needed. Will these really help? Also the ideas of having dampers in the duct system also help with this problem? If so since it does fine in the summer would the dampers have to be adjusted for both winter and summer?

As far as the duct sizes go, I do believe they are all 7 inch drops going to all the bedrooms that are all only 120 square foot. An the master bedroom is a little larger and I do Belive it has a 8 inch going to it.

I guess what is confusing to me is that my old 2.5 ton system did fine for both winter & summer. The only change was going with a heat pump over strip heat. The backup heat stayed at 10kw. I think alot of the company that installed my system and the tech that was just out is going to work on ways to help resolve the problem. I know a load was done on the home as I watched the sales professional do it this past summer and he showed me the results.

Thanks for all the help! As this has turned into a interesting discussion and I am learning alot. Any further information on possiable causes of this problem would be great.

[adamwhatley]

I just looked at the ahri info. For this system. Cooling cap. 32,200 with cfm being at 1050 and heating cap. 29,600 at 47 degress. I noted that at 17 degress heat cap. 17,700. It ahri number is 4385450. This is the sheet that was given to me for tax credit purposes.

[tipsrfine]

Are the supplies run through the attic? Where is the t-stat located in relation to the bedrooms?

[energy_rater_La]

do you find a difference now..in heating season...with the bedroom doors
open vs closed?
how do you live in the house..with doors to bedrooms
open or closed most of the time?

[adamwhatley]

[QUOTE=tipsrfine;12299331]Are the supplies run through the attic? Where is the t-stat located in relation to the bedrooms?


The t-stat is in the living room away from all the bedrooms. We have tried it both ways doors open & closed no difference. The duct work runs through the attic r-4 flex with 6 inchs of insulation over it.

[tipsrfine]

Since the only thing that has changed is that you went from straight heat strip heat to a heat pump with heat strip back-up heat, and the old system kept the bedrooms warm before, I would say the answer might lie in the heat pump delivering less heat than what the heat strips produce. Since there is less heat being delivered overall, any heat loss through the ductwork in the attic is going to produce a bigger temp difference between what is being delivered to the area around where the t-stat is and to the bedrooms. Also, there is going to be the usual solar loading in the areas of the home except for where the bedrooms are. The new system is not delivering the needed btus to the bedrooms and the area around the t-stat gets satisfied and shuts the system off, and slowly and surely the bedrooms experience a greater temp difference than the rest of the house.