# Looking for a type of timer relay



## Revolver (5 mo ago)

I have a job site with a pair of Honeywell true steam humidifiers that are each installed on the supply plenum of First Co air handlers with integral cooling and hydro-air coils. In my geographic region there is a need to add moisture to the air during heating season.

I do not trust the homeowners to always remember to shut off the humidistats in the springtime when they switch over to air conditioning. I do not want to allow the possibility of that oversight to happen.

Here is my idea: All 24 volt. Envision that the hh terminal wires between the humidistat and the humidifier get ran through a contactor relay.
This relay is sequenced to begin perhaps upon a heating call to W. This sequence acts on the heating signal to activate a timer of perhaps 30 minutes or greater. During the 30 minutes, contact switch remains closed where hh passes through.
This would allow the humidifier to function during that window of time after a recent call for heating.

This would bar the humidifier from functioning at other times such as cooling season or shoulder seasons where for a period of time, neither heating or cooling is used.
I know that the simple part is to train the homeowners to shut off the humidistat when heating season is over.

My imagination considers the possibility of the homeowners forgetting and possibly causing mildew growth on the dust that may pre-exist within the ductwork system.
I have seen a few job sites that were new to me, where I found green mildew growth downstream of the blower fans that I have walked away from. A type of situation that I’d want nothing to do with anyhow, but certainly don’t want to allow the possibility to create such a scenario. If the homeowners turned on the a/c while forgetting to shut down the truesteam, I would expect cold saturated ductwork.

I’ve looked at a few defrost control timer sequential relays but the time is too short. Like only 30-180 seconds locally. I’ve looked at 120 volt post purge relays used in Field exhaust power venters but that only gives you like 6 minutes, I believe. I saw some cube relays on-line that have adjustable timers that seemed ideal but they were only 12 volt or 240 volt and product information was limited and didn’t specify whether or not the contacts were dry. Product description also appeared to be written by a person whose primary language was not American english. Anyways…

When I feel good about this I will also enable a feature on the humidifier that can power up the blower fan and humidifier simultaneously when there isn’t an actual call for heat at that moment.

In the end, when I can find and implement this type of control, which I consider a safety against my concern, I could feel confident that nothing bad is going to happen.

About a week ago I had reached out to my usual contact at a local manufacturers rep who supports Honeywell products, but so far all I hear is crickets. Do you kind folks have any ideas?


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