Lennox - Dual Stage, Zoned system questions

[Vacek]

All,

I'm a residential owner on the east coast of Canada. I had a dual zone system installed exactly 1 year ago, and have had nothing but problems since day 1.

I have a Lennox XP16-048-230-05 Dual-Stage Heat Pump and a Lennox CBX40UHV-048-230-6-02 Air Handler and a Lennox CBX40UHV-048-230-6-02 HRV for reference. I have a programmable thermostat on the main floor of my 3 storey home (controls basement and main floor) as well as a basic thermostat upstairs. The main floor is not using scheduling, but set at 70 degrees 95% of the time and is not touched. Upstairs is set on 68 degrees and is almost never touched either.

To date, I have had duct issues, which I believe are all now repaired. Zoning issues which seem to be now resolved. Most recently, I have gone through 4 seperate instances of the outdoor unit freezing up like an icecube. I have been 1 week now with no freezing after 2 boards being replaced, grease put on a few sensors outdoors(?) and replacing the 2 month old filter with a new one (which I keep replacing every 3 months for good measure). The inside unit's coils were clean, no issue there. These things, amongst a few tweaks to the outdoor unit which I could not specifically talk about. I like to think of it as guessing what the problem is by turning a few knobs and dials to see if they get lucky. The fluids were apparently checked and no leaks seem to have been found. So a week of no issues, but no clue what might have fixed it, if it is fixed.

My outdoor unit is constantly NOISY ... and would wake you out of bed when it turns on and off. during the last few days, it runs noisy all the time. (and I mean noisy to the point where the TV needs to be turned up inside the house, 60 feet away from it) My opinion is that the compressor was under so much stress due to all the freezing, that some damage has been done to the unit. Thoughts ? As well, and I'm not sure how the 2 stage should sound, but it seems to be either on or off .. and always the same noise level. I understood that a 2 stage system would run on low or high speed based on what was being called for .. but to my untrained ear, it always sounds the same.

Also, during all the fiddling with the system, they have set the "fan" on the thermostat on the main floor to Auto, and upstairs it is on 24/7. So what happens is that when no heat is being called for, I have cool air always flowing upstairs, 24/7/365. Should this (or any fan) always be on ?? I was told one of them had to be, but am not convinced.

The HRV is set to 80% and is also on 24/7/365.

Sorry for all the rambling, but I spent a ton of money and my heating bill's are through the roof in my home. I have an ICF foundation (with rigid foam under the concrete slab), sprayed in foam in rim joist's, 2x8 construction with rigid foam under vinyl siding, etc .... a very well built and insulated home.

Any thoughts, suggestions or comments are welcome. I have asked Lennox at this point to replace my outdoor unit. Awaiting response now.

Vacek

[Vacek]

I'm sure I confused everyone to no end :)

Any and all comments welcomed.

[hvacmike85]

the fan running 24/7 is not a bad thing, mine runs all year too. They might have left it on because if upstairs is not calling for heat and downstairs is you might have a prob if.... your duct isnt sized to handle the whole load of the equipment with only one zone calling which might explain why it only freezes occasionaly because most of the time both zones are calling for heat, meaning not enough airflow would freeze outside make sense? Just maybe somethin to think about, was you duct always zoned? A hp is supposed to frost not freeze and thats why they have a board outside to do so but replacing it wont fix low airflow or other problems within your refridgeration circuit

[hvacmike85]

and no you cant tell the diff from 1-2 stage is the noise loader than before, some units today are noisy compared to older r22 units but if you got a high end unit as you stated it should be alot quiter than the basic

[skippedover]

I'd like to help but there's so much information of a technical nature that missing here, it's very difficult. Zone installations require a very scientific, solid system design. I have no idea what zone control system has been used in the home but here's the basics.

The system has been sized to handle the entire area for which is is responsible. That area has been chopped up into smaller blocks (zones) requiring less than maximum output from the equipment. However, while the equipment can be reduced to only 1st stage operation when trying to heat/cool a small zone, it can only be reduced in output to a certain minimum. If the zone can't handle all the air that's required at that minimum airflow setting, then one must deal with the excess airflow accordingly. The method used to deal with the excess air is called the "Relief Strategy". Sometimes, that's a sophisticated zone control system that will 'shunt' excess air to other zones. Sometimes that strategy is a by-pass damper (electro-mechanical or barometric) in conjunction with a plenum thermostat or sometimes (less frequently) it's a 'dump zone' where the excess air is just directed out of the system. Not knowing zone capacities or which strategy was used to deal with excess airflow makes it more difficult to comment on your issues.

Not being able to positively establish the refrigerant charge in the system in winter is another issue. If the problem continues, I'd consider having the company remove all the refrigerant, evacuate as appropriate and install virgin refrigerant by weighing in the appropriate charge.

The noise is another issue entirely. If the unit is new and in warranty, I'd suggest you may be within your rights to have it replaced. A well written letter to the manufacturer (address is to the President of the manufacturer, no sense playing with the managers) of the equipment would do a world of good in that regard. Having to turn up the T.V. and being awakened in the night is simply not acceptable.

[Vacek]

Thanks for the comments. Greatly appreciated.

I could not get into the scientific details ... however I can say that I was told that they considered many factors when building my system specs. Lenox was also involved during construction and design (this is a brand new home I just built, and this was installed during the build). I believe the guys are knowledgable and have constructed the duct work appropriately.

As for the HP itself, I heard back from Lennox on Friday. They are prepared to replace the XP16 unit ... however asked if I wanted to wait for approx 60 days when the new "A5" compressor is fully tested and available in their HP's .... In addition, they have offered to replace my XP16 with a brand new XP21 with the new A5 (this will be the first one to market with this new compressor)

At this point, I will suffer for the next 60 days, in anticipation of the new HP.

As for the fan, I'll just leave it alone, and on.