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Rogan 11-13-2012 09:18 AM

Heat Pump concerns at my home in NW Virginia..
I live in NW Virginia. We have a heat pump (3.5T) that's about 8 yrs old. It's in my Cape Cod @ 2100sqft. I had the entire unit replaced in 2005, and retained existing trunks and duct work.

It's no better than the original one we replaced ('87 model) before it broke.

Basically, it's a Trane off-branded unit. there is a main trunk in the crawlspace with 8 feeds to the various rooms (2 to main MstBR, 1 to BTH, 1 to spare BR, 2 to LR, 1 to DR, 1 to kitchen. all of these are like 6" ducts.

Then, here's where it gets stupid...
There's a trunk in the attic. It is fed from the crawlspace trunk via a single 8" duct. Upstairs trunk has 5 6" feeds: 2 to each of the 2 BRs, 1 to bathroom.

2 returns in the house.. one is in downstairs MstrBR, one in Stairwell wall, at the upstairs ceiling level..

The unit struggles to heat and/or cool the entire house, and always has. I've played with opening/closing floor registers to help balance the house, to no avail. The upstairs registers, you really have to pay attention to feel any air blowing from them. they would barely make a candle flame flicker..

Downstairs, the MBR is the closest to the main unit in the crawlspace, and the air (in HEAT mode) comes through the registers nice and warm (temp control set to 70*F.)

The kitchen is the furthest away, and it has no warmness to it; it feels like room temperature air, or as if only the fan is on..

Upstairs feels the same as the kitchen does. I've installed ceiling fans in each BR, as well as the LR and foyer. I change the fan directions with summer/winter.

Summer, the AC acts about the same.. MBR is coldest, kitchen and upstairs, not so much. Summer brings about a 10*F difference between up and downstairs..

I'm at a loss. I think it's mostly due to a poorly designed ducting system, but I am not sure..

HVACDave 11-13-2012 10:52 AM

How large are these 2 returns that you have? From what you are saying there are 8-6" feeds off the main as well as 1-8" to the attic. The 5-6's in the attic off of the 8 are irrelevant at this point as they won't be getting enough air to function properly.

Rogan 11-13-2012 12:39 PM

Upstairs return grate is about 12" x 24". Same for downstairs one.

I added a second 8" feed to the riser thingy for the attic trunk feed and it picked up a little more flow but nothing significant.

Thank you for responding, btw.

Done That 11-13-2012 02:27 PM

Sounds like your on the right track with the duct work being the issue. You can certainly do a quick check of the temp rise/drop at the unit to see what is is doing and then that will help see if the losses are principally through the ducting. Maybe you are able to seal some leaks, maybe some sections have broke loose and are disconnected etc where you can get some minor improvements DIY...but likely you need to drop the $ to have the ductwork done right by a good tech.

Rogan 11-14-2012 07:51 AM

thanks. I checked the ductwork in the crawl space, and didn't find any leaks. Playing around with my digital grilling thermometer, I saw about 6* warmer room temps between the back bedroom (downstairs), which is closest to the heat source, and the kitchen, which is furthest from the heat source, yet still downstairs. There was about 10-15* warmer in BR than Kitchen at register. I can try to find a better way to test temps this evening. I know it got down to about 29*F last night, and the unit ran almost all night. I'm scared to see what my electric bill is going to be..

Done That 11-14-2012 08:03 AM

Is the current ducting rigid metal, or flex duct of some type? Trying to understand if it is insulated at all.

Rogan 11-14-2012 08:05 AM

it's like a flexible insulated tubing..

Done That 11-14-2012 08:15 AM

OK good. I picture or two might really help to get some feedback. Flex can be done really well with smooth bends, or just kind of thrown in with a lot of pressure drop from kinks and not being hung in straight runs, and proper diameter sizing is huge. Would want to see the supply air side to see how the plenum was constructed and how the flex comes off of that, and as another poster menionted the return air side as well.

Again, either that or talk to friends and neighbors...find a reputable local tech and spend the $ for an analysis and second opinion of the ducting. Sounds like you could get your payback fairly quickly for the $ invested to correct this...

Rogan 11-14-2012 08:17 AM

I'll get some pics, possibly this evening..

jagans 11-14-2012 06:08 PM

Heat Pump
Heat Pump in W Virginia?

Sounds like a non starter. I had a heat pump in MD, with regular indoor ductwork. My wife called it a "Cold Air Pump" I would never own another one. I think they might work in South Carolina and South though.

Im not trying to be a SA here. If you have a crawl space with a heat pump you are pushing chain, IMHO.

Rogan 11-15-2012 07:58 AM

Northwestern VIRGINA, but climate-wise, it's about the same.. :(
I don't know what you mean by 'non-starter'. It's now a cold-air pump. Damned thing ran all night long and it was 66*F in the house this morning (thermostat set to 70*F).

Wife just called and said it's 62 in the house.. !@#$%&...

Done That 11-15-2012 09:14 AM

I guess I don't understand why the electric strip heat is not kicking in to help bring up the temps if the HP can't get to setpoint?? It's not that cold out yet. Do you know what kw size backup heat you have and do you know if it is working or not? You would feel a definite increase in outlet air temp when they cycle on.

You have had this system since 2005...are you saying it has performed this poorly every year?

Rogan 11-15-2012 09:28 AM

It's a Carrier 10 Seer 3Ton (looked at it this morning)..
It's always been "meh" as a heat source, but this year seems worse than all before..

I don't know if the AUX heat is kicking it. the "new" thermostat is different than the old one. The old one had an AUX led that lit up. this one (Honeywell) doesn't. Who knows.. maybe it isn't even engaging the aux.

I talked to the service place that installed it (their records showed 2003, so I was off a couple yrs.) and he informed me that the freon may be low. I didn't know that was a factor with heat.. shows what I know about HVAC heat pumps, huh..

He told me he can send a service guy out for $75 first 1/2hr, and $75 every hour thereafter.. I choked a little. Apparently, R22 is (right now) 68$/lb. Told me to turn the unit on, and feel the freon piping. if it's luke-warm, then it's low on freon. If it's hot hot, then freon is fin and it's another issue..
So I'm taking 1/2 day off today and going to go home and check a few things he suggested, as well as what you guys have suggested..
Results to follow, with pics as requested..

Done That 11-15-2012 09:35 AM

You should at least be able to force strip heat on by switching the stat to Emergency and see if it turns on.

Yes, with the compressor running in either heating or cooling mode proper charge is essential to proper operation.

jagans 11-15-2012 11:39 AM

Non Starter response
By non starter I mean that in my opinion you have the wrong type of heating system for where you live. Pushing chain is well, go ahead and try to push a chain.

In my opinion, you would be better off with something like a vent free, or direct vent gas log or two that runs on NG or Propane. Nice ambiance, and plenty of heat. I have one of these running right now and it heats the whole house comfortably. I run the circulator fan in my furnace (Which is down right now, as I am awaiting a part) to keep the temperature even throughout the house, and to filter the air. Send me an email link and I will give you a link on where they sell these pretty cheap. I don't think we are supposed to post retail stuff here, not sure.

I would think that you might have some legal recourse against whoever put that system in. I mean it does not even serve the purpose for which it was intended. The problem is that it will definitely be cheaper to put in an auxiliary heat source than it will be to pay a lawyer, regardless of where you live.

Another poster mentioned your heat strip. They are right, it should kick in to supplement the heat pump. You can tell it has kicked in by looking at your electric meter, it will be spinning like a top at about Mach 3. Basically is is a giant toaster (Dead Short) wherin coils of high resistance wire heats up red hot. These are wired directly to your breaker panel through your wallet.

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