Quality %RH Sensors?

[MCP]

I am looking for both OA and zone %RH sensors that will last a normal length of time in a natatorium environment?

Currently they are JCI combo temp/RH sensors but they have been repaced at least once a year since we have done maintenance at this facility.

[eriks1954]

I have tried a few in that sort of environment looking for the best combination of long life and valve. The best I found was a duct sensor by Veris Industries that has a replaceable element. They don't last any longer than the rest but the element is much cheaper than a new sensor and very easy to change. Not sure if they make as space sensor with replaceable elements but you could check their website.

[SuperDuperTech]

We have good use from Kele KHO units. They have less surface area for chemicals to activate upon.

[ntrg8]

Expensive but they work very well in harsh environments.

http://www.vaisala.com/files/HMT330_Series_Brochure_in_English.pdf

[kontrolphreak]

Expensive but they work very well in harsh environments.

http://www.vaisala.com/files/HMT330_Series_Brochure_in_English.pdf

What he said.

kontrol out

[TriWorksInc]

I just installed RH controls from Johnson, used Humidity control, Humidity display module, and Humidity Element w/ Temperature sensors. So far very nice control of the pool area. I'll let you know how long they last. Just a note, with the display module the customer can see what the actual % of humidity and set point of control and can be remote mounted.

[osiyo]

The best I found was a duct sensor by Veris Industries that has a replaceable element. They don't last any longer than the rest but the element is much cheaper than a new sensor and very easy to change. Not sure if they make as space sensor with replaceable elements but you could check their website.

Yes, they have a series of space sensors with replaceable elements.

[Control Loopy]

Had a job a few years ago where the first set of sensors lasted six weeks, before they began to drift. It's the treatment in the pool which eats the elements - and there are more than one types of purification chemical.

This pool had 'ozone' from memory, and the only units which we managed to find suitable were from Rotronic.

The sensors were more expensive, but you could tell they were quality, they read well, and we never had a call back.

Try and find out what treatment(s) are to be used, and this may help your selection process.

Hope this helps.

[bob_scheel]

We have a banana ripening room system that the humidity is kept in the high 90's. Had trouble with accuracy even though we had used several different sensors. After looking into it we found that these capacitive film sensors can be saturated if they are exposed to humidities higher than 90% and will read improperly until they are kept in a low humidity environment for several hours or days.

[osiyo]

We have a banana ripening room system that the humidity is kept in the high 90's. Had trouble with accuracy even though we had used several different sensors. After looking into it we found that these capacitive film sensors can be saturated if they are exposed to humidities higher than 90% and will read improperly until they are kept in a low humidity environment for several hours or days.

Quite normal, in my experience.

You might consider investigating a ceramic coated resistive type humidity sensor. They tend to perform better than capacitive film sensors at high humidity levels (>=90%). Recovery times from total saturation (immersion) tend to be measured in minutes.

OTOH, capacitive film humidity sensors tend to perform better in the < 20% humidity range.

[gnomethang]

Third plug for Vaisala. If they can't then nor can anyone else.

[brentstex]

I'm not a fan of JCI but we have seen some pool dehumidifiers come with JCI branded humidity sensors that have lasted for 10 years and are still accurate. JCI may be changing their suppliers periodically though. So there may be something unique to the chemistry of the particular pool you are dealing with, or perhaps a generation of RH sensor. Is is chlorinated water or salt water? There are also bromines that can cause troubles in various mixtures.

We have had seen Greystone products that were 10 years old installed by others and still working. So I think there are other options if the customers budget won't support Vaisalla.

[amigo]

I guess everyone's experience could be different.
My vote is also for vaisala as well.
Greystone is by far the worst humidity sensors I have ever used.