New to this forum. I have a new home in SC that has a Three zone HP. It is a Lennox x-16, two stage, with elect. back-up, and a Harmony III control board. I have had a/c and heating issues from the start( at least 25 service calls), which allegedly were fixed with a ductwork redesign.

Since it desn't get too cold down here, it's been tough to determine whether the system is working right. I have noticed that the heat cycles on/off too frequently.

Last night was our first cold night. Temp went down to 26 All three of my thermostats were set at 73. The system literally stayed on from about 10:00 until about 9:00 this morning. During various stages of the night I noticed various combinations on the control board from two stage heat, with sometimes one or two electric back-up stages kicking in. It appears that the system cannot keep up with the insied temps of the house. The house never seems to be comfortable. Back when we were up in Pa. we never had our thermostats set so high and we had elect baseboard heat.

I am awaiting the a/c guys to come one more time.

Please give me some input. This system is driving me nuts.

 

grady

What size is your home?

What size is each zone? It is necessary to heat all three zones simultaneously at 73 degree heat?

What size is your heat pump? Your system was sized for heating at 73 degree inside temp?

each zone was maintaining your thermostat setting?

You have two heat strips that are staged?

Post back.

 

The home is 2245 sf heated. It is a four ton unit. Zone 1 is the main living area. Zone 2 controls a 12x15 sunroom. Zone 3 is for a room over the garage, about 15x28.

The reason I had all three on 73 deg. was to see if the system could handle it since I've had so many problems.
The only zone to apparently go on and off was zone 3. The other two remained on constantly using both stages of the system along with one heat strip and occasionally the second heat strip.


Any assistance would be appreciated.

 

Id think so too. First what did the load come out on the home with the J manual?????.
Then a 3 zone duct work set up in a home of 2245 sq ft. Id say no way. With a 2 stage unit?????.
Id say you have a bad lay out of the duct work with where the bypass dampers are in for the zones.
This is why we do not use zones in homes at all . We put another unit in where and how it is needed. Had two homes the same One we did with two units the other was did with 2 zones in it one unit. The power cost for the year is about a 1/3 less On the one we did with two units

 

jeepgrady

Zoning control boards to handle HVAC needs for multiple zones from a single HVAC system are installed every day and are successful. It is not for the faint of heart or inexperienced. By now, I would have called Lennox directly. Obviously your dealer is not up to the task and requires assistance. You have two small zones and one large. I don't really understand the shortcycling or the fact that your unit ran constantly during the recent moderate freeze for our area. In fact, I am puzzled that your heat strips engaged at all. Sorry for your trouble but don't give up. Hold the dealer responsible till he gets it corrected. And please keep us posted.

TD

 

"Not for the faint of heart or inexperienced" is so true. So far the builder has had three companies come in including the original installer. Lennox also had sent reps. out back when I was complaining about the a/c. They came up with a plan to reposition the ductwork among other things which has been done. On the other hand, the builders rep was on the phone yesterday with Lennox and they told him that the system appears to be working as designed.

It is very true that these zone boards are very complex and from what I can tell most of the techs that came here had little to no experience.

The current company seems to have the most knowledge and they are not giving up as yet. As I speak, they are again up in the attic checking other things.

One more thing, during the never ending overnight cycle I get an "insufficient heating" error code. While I obviously know what it means, what do you think the corrective messure is?
You mention our area. Where are you located?

 

jeepgrady

I live in upstate SC.

Any idea what your cooling and heating load is? Did you get a copy in writing? It should have a total BTU for heating and cooling plus each zone should be broken out individually.

Your error code on "insuffient heating" is another puzzle. You should have plenty of heating BTUs.

What size are your heat strips?

TD

 

I live in Murrells Inlet.

No clue about the heating load. I beleive that their is onlt one heat strip @ 10kw? Supposedly stage one will activate 5,then stage two will turn on the additional 5.

 

jeepgrady

hang in there and don't let these HVAC guys wear you down.

Murrells Inlet...hummm one of my fav locations.

In fact Franks Out Back is one of favorite eating and watering holes. Years ago, it was Oliver's Lodge,Wayside,and Lee's Inlet. Oh well, making myself hungry.

Good Luck!
TD

 

jeep

any update on your HP and zoning problems?

TD

 

The HVAC guy came by and said he found a damper that was fluttering whch could have restricted the airflow a bit.

Now that the weather is tempered, the unit seems to be working OK. Of course, when the overnight temps only fall to the mid to lower forties, it should. I still hear the unit going on/off during th night but without the same frequency. I think that part of the problem is that there is a very small window between the temp. spread between cycles. It's like the system wants to maintain a constant temp as opposed to going up several degrees above the set temp when on, turining off and then back on when the temp goes back down to the set point. The HVAC tech said that's the way the digital stats work.

Builders rep. was here. They conversed with Lennox and Lennox told them that it sounds like the unit is working as designed for the set up in this geographic area. Well, I told the rep. that if this is the case then I want it in writing from Lennox. I then informed him that if Lennox is not willing to do this, that they are full of S---. Builders rep. also stated that their cintractor also feels that everything is now working as designed. I still find that hard to believe.

I was speaking to another neighbor at a Christmas open house. This neighbor has the same home and the upgraded system as I. He told me that his unit worked much the same as mine during the cold snap. Coincidence? or are they both screwed up.

Now, we are expecting temps down to about 20 on , I believe Tuesday night. I'm sure that my system will be on all night again. Time will tell. However, I still believe that there is a problem.


Any additional suggestions will be greatly appreciated.

 

Sizing a heat pump is no walk kin the park. If not done right, the balance point ends up being too high and you're stuck with having to live with the strip heaters kicking in and out and running up your electric bills.

Heat pumps are also notorious for not being able to deliver air nearly as warm as nat. gas or #2 oil would...it's the nature of the beast, so it is important to help the unit get the job done. At its best, a heat pump would deliver air at a temperature in the low to mid 90's. So here's how you could help this baby do its best:
(1) is your house drafty? ---seal windows/doors as needed
(2) are your ducts tight? ---check and patch leaks as needed
(3) is your duct uninsulated and runs through an unfinished basement or an attic? ---add duct insulation

Yeah, none of the above recommendations would seem to have anything to do with your heat pump...but you'll see a big difference by implementing them.

 

I appreciate your feedback. The house is brand new. The windows are double pane and the house has exterior house-wrap.
The ducts have been examined and there are no leaks.

While all of the ducts are in the attic, since they are new they are of the core within a core type, meaning that they are fully insulated.