[ga-hvac-tech]

Not to start a new argument, but some of the dirtiest systems that I had to clean out whether it was the a coil or the secondary heat exchanger or the blower, have been coupled with electronic air filters that did not get maintenance

Yeah... the sad thing about electronic air filters...
They need cleaning quite often.

I have pulled a bunch of them...
And yeah... the equipment was messy!

 

[WAYNE3298]

Doing air balance I have ran into AHU'S that had pre-filters and bag filters so dirty they were sucked out of their frames and stuck in the coil.

 

[Adlerberts-Protege]

This thread has turned into real awesome discussion. Maybe I should have it renamed and put in the technical forums. I think we should get more in depth on static pressure tests vs duct traversing and TAB. I am here to learn like everyone else.

 

[WAYNE3298]

Adlerberts you lit the candle and as usual on this site something good comes out of the flame.

 

[Adlerberts-Protege]

Well then lets keep going on this.

Did another static pressure test today. Post-filter, .27 R/A.
S/A was .17

I think our duct designers are doing a pretty good job in residential. A lot of it almost feels like commercially engineered system designs. I do feel it is much better than a lot of stuff throughout the country and it makes me smile actually.

The last place I worked for in Portland had no such systems in place. We didnt check static nor gas pressures nor even anything remotely near TAB.

 

[Adlerberts-Protege]

Its a young crew mostly in their 20s and I feel they just need to get the big picture. Had a meeting with my boss today and we both agreed lets turn this shit around. Maybe this is the landing spot I get excited again.

 

[Core_d]

if I can get a hotwire on the cheap ill be happy to post a some comparisons:grin2:

Question fot you Wayne.. could you use a hot vane rated for say 4000cfm on a very large system by doing sections of the duct at a time and add it up?

 

[WAYNE3298]

Those statics look a lot better than the others. Do you guys normally have fan curves or tables?

 

[Snapperhead]

Its a young crew mostly in their 20s and I feel they just need to get the big picture. Had a meeting with my boss today and we both agreed lets turn this shit around. Maybe this is the landing spot I get excited again.

ut oh ... theres a new sheriff in town

 

[shellkamp]

ut oh ... theres a new sheriff in town

Excuse me while I whip this out.

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[Core_d]

Excuse me while I whip this out.

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Drop your jocks and grab your socks boyz...


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[WAYNE3298]

Core_D I assume you are talking about doing a pitot traverse with a hot wire anemometer. If so as long as the velocity pressure doesn't exceed the capability of the instrument (which is unlikely) the answer is yes. Duct traverses are done one reading at a time and all readings added together and averaged to get total airflow.

 

[BALloyd]

If you read the installation manuals on many of these electrostatic air filters, especially the Honeywell ones, they actually state the best practice is to install media filters upstream of them to catch larger particles and keep the electrostatic cleaner, since they are best are removing smaller particles and quickly loose their efficiency when subject to poor maintenance.

I don't know anything about how they are or if maintained. The only ones I have seen were new. Other than cleaning what do they need?

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[WAYNE3298]

BALloyd based on what you said it appears the electronic filters main purpose is to fine clean the air. Is that a fair assumption?. If so AHU manufacturers need to re-evaluate the fans installed in their units and make additional static available. I have been convinced of that all along anyway. When you do air balance and struggle to get enough airflow to meet the minimum allowed by the design on almost every unit you hate to see residential units installed in commercial applications.

 

[knave]

If I recall rightly, the reason .5” is the standard available static pressure is due to noise. Especially with “fan auto” and residential settings.

 

[WAYNE3298]

knave it is noise but also cost. The problem also faced with adding available static to these units is space restrictions. The units almost always work well enough to condition the space unless under sizing of ducts etc. It looks like if there is a swing to adding electronic filters more static may be needed to meet the filters requirements. Would you guys agree?

 

[knave]

knave it is noise but also cost. The problem also faced with adding available static to these units is space restrictions. The units almost always work well enough to condition the space unless under sizing of ducts etc. It looks like if there is a swing to adding electronic filters more static may be needed to meet the filters requirements. Would you guys agree?

I agree, but doubt we will see it.

 

[WAYNE3298]

Sadly knave I think you are right.