Uncontrollable Humidity

[ffmus]

I work in a museum for the sole purpose of trying to trouble shoot major HVAC control issues. The system is in 3 parts, one complete system per floor all controlled by Carrier Comfort View v.3. I have the temperature and humidity controlled on the top two floors, however the basement humidity is off the charts and air conditioning is not controlling it. The system is a carrier forced air furnace, carrier AC unit, Lifebreath HRV, and DriSteem VT-4 Humidifier. The wall humidistat is set at 50% and the actual room humidity is 74%. I manually shut the humidifier down and increased the ventilation rate to try to dry out the air but am looking for some guidance to permanently fix this issue so the controller will look after it. I am totally stumped and looking for any ideas!

[swoosh172]

Depending on what area of the world you are in, increasing the ventilation will actually increase the humidity level in the room if the unit wasn't designed for the increased flow. Have you checked the outside air damper to make sure it is correctly positioned and not broken? Try lowering the room temperature setpoint to get the compressors to run longer and accumulate some more moisture on the coils. Does the unit run 24/7 and are the basement walls insulated?

[ffmus]

I am in Canada, more specifically Northwestern Ontario on the Minnesota border. The outside air damper is operational and not broken. I have very little control on the set point because the building is a museum and must conform to strict air quality guidelines. The unit runs 24/7 to maintain (or try to) a very strict temperature and humidity level. The basement is insulated, however does leak a little during and after heavy rain events (1898 building....) This just adds to the issue......

[teddy bear]

Minimal fresh air when the outdoor dew points are above the desired inside dew points. Next get a powerful dehumidifier, like the Santa Fe MAX Dry. It's a 150 pint per day dehu and use only 7.9 amps. Basements do not need enough cooling to remove the moisture that is in outside infiltrating moisture plus the moisture from the occupants.
REgards TB

[ffmus]

The Basement is only storage, with the exception of maybe a few minutes a day, there are no occupants. I am hoping to get sufficient dehumidification with cooling and ventilation until I can go through the necessary steps to get a dehumidifier

[Control Man]

Almost Record rainfall here in Ontario lately has added to the HUMIDITY problems all over.

Any chance of finding out how the conditions were in the past ?

[ffmus]

When I started here (January) the humidity was 4% I was able to re configure the software to get the humidifiers working and the humidity controlled around 45-50%. Once Spring came the humidity climbed to around 60 (higher in the basement). Once the AC came on the humidity came back down to mid to high 50's however I can not get the basement to regulate unless I manually shut down the humidifier. Once I get this system refined I will not be in the building to manually shut things down so I need to figure out how to get the software to look after it (or worst case get a dehumidifier)

[ffmus]

Just an update, humidity is back up to 74%. Humidifiers are either on 24/7 or off 24/7 I am looking for some guidance on how to get ComfortView to control the humidifiers based on the space humidistats. Any help is GREATLY appreciated!!

[madhat]

Next time it rains, put on your rain gear and go outside. Look to see if your storm drains are clear and have water actually running in them. If they haven't been cleaned in a while, have someone Jet rod them that has a Camera on the Jet Rod. Do you have "Lambs Tongues," Brass drains on the outside of the building? If they are running water, your roof drains are clogged, and they are handling the overflow, and unfortunatly putting the water next to your foundation. Where your basement wall attaches to your first floor wall is there a gap there? Sounds like you have a lot of infiltration with 4% Rh in the winter.

We have a Library, that had extreme moisture problems, I cleared the leaves out of the roof drains. I noticed little to no water running in the parameter drains when raining. Happen to catch the Jet Rod contractor, he cleaned and checked the drains. Found a collapsed section, that was replaced. We had water running in the Mechanical room when it rained. Now it is dry as a bone.

[dfelt]

I'm with a cple of others in that I think you have bldg/vapour barrier issues.The humidifier should have a controller which incl.humidity setpoint as well as high/low enable points.
I would think that during cooling season and esp.w/basement that the humidifier shouldn't be required/allowed at all.
Dehumidifier pronto lest the "M" word pops it's head {black mold}

[dfelt]

Can you find info.to check hygrometer specs.?

[ffmus]

Thanks to all for the help!!! There is not a doubt in my mind that there is major infiltration issues, the building was built in 1898.... I went DEEP into the controlling software and found some more settings that were not allowing the humidifiers to be controlled by the space humidistats.....(someone has done some major monkying with this programming!!) Things seem to be controlled now (approx 45% RH on all 3 floors) so HOPEFULLY I am running out of weird issues with this system! Thanks again for the help and insight!