ERV supply smells wet and damp
Have a new construction (2024) in MA. Basement + 2 levels. Decided on heat pumps for everything and went with LG for HVAC and Panasonic for ERV. We have one erv and hvac in attic for top floor and another erv and hvac + whole house dehumidifier in basement for main level and basement. It’s a 4100 sq ft home (1000 is basement). Ducted with dedicated ducting for ERV.
the bedrooms in the main level (2) and the basement smell of wet socks/dogs….. we have no dogs…. Nor wet socks.
While it’s been humid in MA, there are days where it’s 75% in those rooms but 54% outside and the dehumidifier is stuck at 60% – its set to 45% – it’s never gotten there.
both ERV are set to 70 supply and 70 return, I did want to run it at 80 supply and 60 return, but for now I have it on just a balanced setting
what I do know is that the fresh air intake is maybe 2’ off the ground, while it doesn’t smell like wet socks out there, it just always does if you were to get down and smell the air coming out. I’ve changed the filters on these.
I’m not sure what the best step is. The dehumidifier is the 80 series from aprilair, the next step up is 100,. But I’m not confident it’ll solve the issue with the dampness and smell from erv supply. The dehumidifier does a return to supply, and I’ve noticed it follows the proper airflow direction when hvac is off but when it’s on the return pull from blower is stronger then the dehumidifiers fan so runs in reverse flow – but still would dehumidify
We could try and put a snorkel type duct in that fresh air intake so it’s 5 feet of ground but I don’t think that’ll really solve it either.
any suggestions on what to try next? (The hvac co is looking at it but I don’t think these guys are completely knowledgeable on erv) – only other thing I can think is to take the erv supply, shove it into dehumidifier and then connect the supply odd dehumidifier into those supply ducts……… seems silly but not sure what else to do.
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Sounds like you have construction moisture. For a new build you need to run extra dehumidifiers for the first year to dry the house out.
You also mention the hvac shutting down. The LG units are typically fully modulating, which means it should be running 24/7 unless oversized or using the wrong thermostat. Oversized hvac or wrong thermostat don't help with humidity removal either.
Since you do have two units, one option I had good luck with for drying a place out is to put the upstairs unit into dry mode (this tends to overcool the place) and set the main floor unit to heat to keep the place comfortable. This isn't all that expensive to run and as bonus you get nice cold bedrooms upstairs.
Thanks for responding.
For LG I have LV361HHV4 with LUU360HHV / they fans are set to auto; so when I say shutting down I mean it reaches it set cooling temp and fan cycles off. It does have circulating mode or always on for fan too. - I’ll have to see if this model has the dry mode, the thermostat itself doesn’t. I installed the Honeywell pro wireless ones, can lookup model number.
It’s just the erv supply in those 3 bedrooms that smells that way. All other rooms smell perfectly fine / esp the upstairs rooms., the construction moisture should also exist in the other supply runs if that was the case - no?
First, get yourself some independent humidity sensors if you don't already have them. Accurite on Amazon are about $15 each. Make sure your humidity measurements are accurate.
Second, it sounds like you may have two separate issues:
1. Humidity is too high in the house.
In the first year or two in a new house there is ALOT of moisture, but I can't imagine the humidity being 75%. That sounds like either a very leaky house, a source of humidity (do you have a steam shower or sauna?) or a grossly oversized HVAC that reaches setpoint without dehumidifiying. Your ERV is not meant to be a source of humidity control; that is the job of the HVAC in the cooling season, and the dehumidifier in the shoulder seasons.
Look on your electrical panel and see if there is a sticker on it showing the result of the blower door (air tightness) test for the house. Should be expressed in ACH @50 pascals.
Also check that your dehumidifier is truly dehumidifying. If it is a whole house dehumidifier, remove the filter while it is running and look to see if there is ice on the coils. If so, that is part of your problem.
2. If I properly understand your post, the supply air coming in via your ERV smells like wet socks or a wet dog. Is your ERV in any way connected to your HVAC system or is it separately ducted?
3. You wrote "I installed the Honeywell pro wireless ones..." about the t-stat. Did you by any chance remove and replace the t-stat that came with your LG units? If so that could be a big part of your issue. Heat pumps do not work on just any t-stats. They are specific to the heat pump unit.
Thanks. Will reply to your ref points.
1. On the herc report I see house tightness is 1.26 ach50 / no sauna, no steam, it’s just those 3 bedrooms with erv supply that read high humidity based on the portable dehumidifier but I can get a tester/reader. When the HVAC blower is nut running and dehumidifier is, if I loosen the drain pipe there is water leaving it. When the blower was running there was/is just a drop or two…. Could have been timing or….
2. It’s separately ducted. I also turned off the erv off last night (only the one in attic is running) - and the smell is not there. The bathrooms attached to these bedrooms have Panasonic exhausts that are externally ducted and set to turn on at 70% humidity - these have finally shut off (with the erv off)
3. HVAC people had installed Honeywell pro - non wireless ones. Never saw LG ones on there.
It’s currently 84% humidity outside. Dehumidifier says it’s at 60% - after the hvac guys left yesterday I checked on it and it has a s2, 2e? Code on there. I turned it off and turned it on and it cleared that. When it started it was 70% - when I turned off the erv I also set the blower in circulate mode. - I’m assuming that the dehumidifier itself has no fan? If it does, I’m interested in running it without the blower in circulate or on mode. In auto mode it will only run fan when cooling needs to turn on.
You have both issues. That LUU360HHV is well oversized for the cooling load (also most likely well oversized for the heat), but that ship has saild. Connecting it to a regular thermostat means it runs like a single stage unit, so humidity removal and efficiency would not be great.
I would look at getting the LG thermostat installed which will let it run in modulating mode. You can then set the system to run the fan speed at its lowest setting which helps with humidity removal.
If your air handler is overwhelming the dehumidifier, I would remove it from the supply duct. Have it dump the dehumidified air straight into the basement, that extra bit of sensible heating is usually a good thing there. This will also let your set it to run continuously not just when the air handler is on.
I think once you get house humidity under control, the smells will go away.
ERVs cores also do have a smell when new, this takes a month or two to dissipate, I don't think this is the issue in your case though.
Thanks!
Chatted with April air. They want the team to call when they are on site to check static pressure. They also suggested that they may change the setup - return-to-supply except the return is from basement directly.
HER cert says total conditioned floor area is 5591 (so maybe not that oversized?) and looks like we need e100 instead of e080
It has now thrown e2 error codes two days in a row. I don’t know if the hvac guys moved it around or what…. But it wasn’t throwing it before. I adjusted it a bit to make sure it has enough curve to not block the duct since it needs that U turn….
Any chance you know the part number for the lg thermostat?
Opening the covers of those erv’s - only the basement one smells the way it does. After solving the dehumidifier issue - will look at doing some sort of contraption/snorkel for that FA supply, take it 10’ or so higher from outside, may look odd but will try and make it look like a gutter or something.
Sounds like they are going to get the dehumidifier ducting worked out, but you definitely don't want low air flow or backwards air flow. It has to cool then reheat, not heat then recool. Very low or reversed airflow could cause the E2 error, which is high refrigerant pressure (too hot). The E080 model's fan loses half its airflow at 0.4" static pressure, so it's not too strong of a fan.
https://rp.widen.net/view/pdf/fl7nmpqzx6/aprilaire-e080-e100-dehumidifier-installation-guide-and-owners-manual-B2210022.pdf
Not sure there's any problem, but it seems like your duct static pressure might be a little high. Is anyone else concerned about that? The E080 manual doesn't give the max static pressure of the fan, but extrapolating, I think it would take 0.6-0.8 inWC to start reversing air flow. Since return-to-supply is one of the installation options, AprilAire must be expecting lower static pressure in many systems.
I'm not experienced, so don't worry if nobody else is worried.
Aprilair asked that they contact them when on site to troubleshoot and verify that it’s not a static pressure issue. It throws error code daily. It’s also likely undersized. HVAC claims that it isn’t because the basement and first floor are less than 2k sq ft which is what this is ducted into. Completely ignoring that the whole house is actually 5800 sq ft. I’ll be calling Aprilair tomorrow to confirm that the correct way to calculate coverage is based on total conditioned space and not just which hvac ducts it’s connected to.
Consider you spent a lot more money to get the comfort and low operating cost a variable speed compressor offers and then connected the equipment to a thermostat incapable of using the benefits you paid for.
Consider paying for the upgrade to the LG communicating thermostat.
Walt
I can see why the hvac crew didn’t install these and gave me $25 (five) thermostats. This seems to $250 a piece and is CRC2 now? Will see what I can find.
Btw - I have seen the outdoor units operate at various speeds, but this was in winter. Assuming it’s true for cooling too.
MultiSITE CRC1
file:///C:/Users/W%20Play/Downloads/im_crc1_series_controllers.pdf
Walta
I am curious how do you know the speed of the compressor spinning inside the hermetically sealed steel dome was changing?
5 thermostats?
Is there a zoning system?
Walta
Yes - There is a zoning system.
I was referencing heat pumps sitting outside - I’ve seen that run at various speeds, you can tell from the vibrations and noise - we already had issues with vibrations and noise on them - we had these mounted to the wall but had to get them on the ground because when they got going, it sounded like a diesel engine.