Bypass Humidifier Location

[mfb]

I have a bypass humidifier mounted on the return (as I suspect many are). However my humidifier is mounted after the airfilter(4" media). The humidifier is located between the Air Filter and the Air Handler. This raises 2 concerns:
1) If any air leaks through the Humidifier it wont pass to the filter before reaching to the coil.
2) The humidifier is providing an air path that doesn't go through the airfilter. Air flows Humidifier, Return, AH, Supply, Humidifier ...
As the airfilter gets dirty, this path becomes less and less restritive compaired to the filter.

Is my humidifier installed in a normal/common/standard location or is this a problem? Where should a bypass humidier be installed? My house seems much dustier in the winter when the humidifier is in use and my allergies bother me more too. I'm suspicious that this is because not as much air is being pulled through the filter.

And just in case it matters. The static pressure difference between the humidifier damper being open and closed is .16 (Infinity controller reading) on a 4-5 month old filter/~50% used.

What do you think?
thanks
MikeB

--
Resubmitteted from the Indoor Air Quality forums which was the wrong forum in the 1st place.
Sorry for the double post.

[tunnel_rat]

Alot of systems use filter grilles in the returns, the humidifier on these systems is never filtered either but you shouldn't be getting air sucked into the humidifier from outside the system if it is sealed and installed properly. If there is room upstream from your filter, you could move it, but I doubt it would make any difference.

[mfb]

That's true, return grill filtering would be the same configuration. I hadn't thought of that. The only difference I can see would be that there might be less pressure drop from the return grill filters because of greater surface area.

The only air sucking I was thinking about would be around the humidifier cover. It's not loose but its not a presure seal either. The bypass duct is sealed with tape and mastic so it should not leak.

So here's what I tried.
1) I taped the humidifier cover closed -- if there was any air leaking it's not how. I just have to retape it when I change the water pad.
2) Had a power duct damper put into the humidifier bypass duct. It's closed when the humidifier is not running and open when it is. Since I always run the fan this causes more air to be forced through the filter.

I not sure how much it really helped but the sinius problems that I've been fighting have reduced significantly (but not gone away). Still it's a start, maybe t just needs more time?

Maybe I need to consider a TrueStream Humidifier and get rid of the bypass humidifier altogether?

Comments or suggestions?
MikeB

[tunnel_rat]

I would dump the bypass and check out a fan powered one. Fan powered humidifiers are mostly what we've been putting in the last few years. It has been at least 3 yrs. or more since I put in a bypass hum. The "water pad" types just seem to be a bacteria factory unless diligently maintained, which most are not. I've never had one on a system where I lived, but people who have them swear by them.