HVAC - Quick Bypass Damper Tutorial

This is a quick fix with very little griping. It's in a new home that happened to be the ONE house in the phase that was duct-tested by an independant contractor. After the repair, the stuporintendant showed me the paperwork generated by the tester. This zone system was putting out about 60% of the air to the supply registers that it was designed to move. The rest was being dumped directly in the return plenum via the poor bypass damper install. The system suffered no damage and the dog is o-o-o-o-kay!

Category:

Education

Tags:

• HVAC
• Quick
• Bypass
• Damper
• Tutorial
• Backward
• Installation

[mazzmari]

Cool video.

What are those bypass dampers used for? I have never seen them up here, probably not necessary for my climate.

[PutSome5tankOnIt]

@mazzmari When motorized volume dampers restrict supply air flow, the excess air has to be diverted back to the indoor fan to aid blower motor cooling. The furnace/air handler doesn't care where the return air comes from. It just needs to move it through the system.

[eazy2day]

nice

[PutSome5tankOnIt]

@FilterChanger The old Honeywell kits (board, DATS, transformer) we installed were the EMM-3's.Two-minute blower on (purge) when first powered up. The LEDs would light/blink red, green or orange. Blinking orange was "no DATS installed"

[FilterChanger]

@PutSome5tankOnIt The old TotalZone boards by Honeywell had a solid purge during the purge cycle, blinking purge meant the DATS was unhooked, or open. I should have a short video up showing an install w/o dats. It's blurry, sorry.

[PutSome5tankOnIt]

@fritzhvac Each run should have a motorized zone damper to control air circulation. That's the best way to control air flow and system performance. The Honeywell systems allow for easier 'daisey-chaining' of dampers that serve zones with multiple trunk lines. It sounds more complicated than it really is. Trust me. My way is the best way.

[fritzhvac]

@PutSome5tankOnIt

Thanks man , I was thinking of maybe drilling out small hole in the back corner of the closet to get control wire up, to Zone second floor (i'm pretty good a finding a way up, look out he's got the DAMN sawzall out again ,RUN) LOL... Is there any requirments on existing furnace ? Does every run require damper ?

Probably sounds stupid , but never done before ...

I'm hoping honeywell has PDF , I can look at ...

[PutSome5tankOnIt]

@Houze968 Yeah. That system will pass the next duct test.

[PutSome5tankOnIt]

@FilterChanger The 'purge' light blinks when the system is powered up. It's usually a 2 minute cycle as the zone board checks components during boot-up. I frequently see the DAT sensor circuit bypassed with a jumper wire. Silly installers... Trix are for kids.

[PutSome5tankOnIt]

@Darvin1964 I don't read directions as much as I used to. I've already seen most situations I come across nowadays.

[PutSome5tankOnIt]

@fritzhvac Thanks Fritz. These kinds of zone systems aren't really complicated. Easier if the trunk lines are already dedicated to living and bedroom areas. I prefer the Honeywells over the MasterZones. I think the Honeywell model # is HZ311K. The hardest part probably is pulling thermostat wires for additional zones on retrofit jobs..