[yonkoc]

Hello,

and a big thank you to all of the folks on this forum. Hope you are not going crazy at home.

I would appreciate some advice on how to wire a fan control center to my existing system. Overview:
1. I am installing a booster fan on a long supply run in a newly built section of the house.
2. I already have an armored 12/2 with a receptacle to where the booster fan will be hooked up. There is no power going to this receptacle presently. The fan is a standard plug.
3. The entire second floor is one zone (Zone 1) and the newly built area is another zone (Zone 2). There is no bypass damper as none of the rooms in Zone1 have dampers. Only the newly built Zone 2 has a damper.
4. Using an EcoJay 4x with Ecobee3 thermostats. Zone 1 has its tstat, Zone2 has a tstat with 1 damper. Single speed fan motor in the furnace.
5. I've got a Packard 90113 FCC, with PR340 relay.
6. 120v presently terminates into a 4x4 box installed next to the control board. I call it Power In.
7. From that 4x4 theres is the 12/2 run going to where the fan receptacle is. I call it Power To Fan.
8. The FCC has black and white 20 AWG leads on the bottom, a black, red and brown 16AWG leads coming out of the relay and the RCYGW terminals on the block. C and G are wired to the coil on the relay. Relay black is pin 1, relay red is pin 3 and relay brown is pin 2.

My goal is as follows: Have the booster fan operate only when Zone 2 calls for heat/cool or fan (Ecobee can run fan only to equalize air and I have it running 5min per hour).

I could be totally off, please feel free to correct me. What I "think" needs to happen is this:
Run wires from R, C, and G on the FCC terminal block to zone 2 thermostat terminal on the Ecojay. This way, fan won't operate when zone 1 is calling and zone 2 damper is closed.
Black from Power In wired to black from bottom of FCC.
Black from FCC relay wired to Black from Power To Fan.
Wirenut the whites from Power In, Power To Fan, white on bottom of FCC and the red coming out the FCC relay.
Wirenut the grounds from Power In, Power To Fan and a pigtail that'll be screwed into the metal box.
Cap off the brown.

My understanding is as such. When Zone 2 tstat calls for heat, cool or just fan it'll energize the R, C, and G, thus closing the NO pins 1 and 3 on the 24v relay, thus closing the 120v hot run from Power In to Power To Fan. Once the call is stopped relay is de-energized and pins 1 and 3 return to NO and cut the 120v going to the fan's receptacle.

Does that look/sound okay or do I have it completely wrong?

A big thank you goes out to everyone. Stay home, stay safe (and work on your honey do-s :vs_laugh

 

[beenthere]

Does the thermostat have the ability to run the fan for an extended time after the heat call ends. If not, you will likely over heat the other zone when those dampers close.

 

[yonkoc]

Does the thermostat have the ability to run the fan for an extended time after the heat call ends. If not, you will likely over heat the other zone when those dampers close.

I'm not quite sure how long the fan spins after the heat call ends. I know the tstat can run it independently of heat/cool as I can program it (I know it works) to run each hour in 5min increments all the way up to 55min per hour.

I'm not sure I understood what you stated. There is a single damper for the entire system, that's on the run to Zone 2 (the Office). When Zone 1 calls for heat/cool that damper closes. When no zone calls for heat/cool then the damper is open. How is it going to overheat "the other zone"?

 

[user_12345a]

I stopped reading after this point...

I am installing a booster fan on a long supply run in a newly built section of the house.

The booster fan is a patch.

A newly built section of the house should have it's own small system (mini-split heatpumps are great for additions) or the entire duct system properly engineered it.

I don't think you'll get very good results with a booster.

Was a load calculation ever done on the addition?

Any major changes to the duct system or did they just add a run?

 

[yonkoc]

Apologies, I do not wish to appear either rude or ungrateful. I do thank you for the questions but we are getting off-topic. Is what I asked doable/correct?

The space is finished with no option to add splits or anything like that due to many reasons, one major one is the HOA restrictions (nothing on house facia), another is that there simply isn't any other way to get air into this space due to existing plumbing, walls, roof line, floor/ceiling elevation, etc.

 

[user_12345a]

No - it's not off topic because duct boosters have a reputation for not working well - what does is having properly sized ducts to the addition connected to a correctly design duct system that can deliver proper airflow.

When an addition is planned, there are supposed to be hvac plans based on a room by load calculation.

The ducts get sized based on requires cfm of equipment, heat loss/gain of each room, and the equivalent length of the longest run.

Was any of that done?

Unfortunately, hvac is often just an after-thought in the planning stages of a major renovation.

When the new addition is on a totally separate zone, there's absolutely no reason why it shouldn't be comfortable.

You shouldn't need a booster fan especially after paying money for a zoned setup!

The booster fan is a patch which probably won't fix the problem and should be used as an absolute last resort.

Wiring it so it only comes on when specific zone's stat calls for heating or cooling is absolutely doable -> may need some creative wiring with relays.

 

[yonkoc]

Thank you, it appears I'll have to handle this on my own. All the best!

 

[user_12345a]

Thank you, it appears I'll have to handle this on my own. All the best!

You can get good help here - I ask lots of questions up front to determine if the proposed solution will actually solve the problem or is a total waste of time + money.

If you are actually interested in resolving the problem, read ahead...

.

I suspect that your duct system was completely botched up when the addition was done.

I totally missed the part about only the second zone having a damper.

Adding damper to the first zone as well as a bypass and upsizing ducts to the addition could solve the problem.

Would take an on-site evaluation by a pro to determine what's viable.

Ideally furnace/ac or heatpump should be 2-stage but single stage can be made to work.

 

[yonkoc]

You can get good help here - I ask lots of questions up front to determine if the proposed solution will actually solve the problem or is a total waste of time + money.

If you are actually interested in resolving the problem, read ahead...

.

I suspect that your duct system was completely botched up when the addition was done.

I totally missed the part about only the second zone having a damper.

Adding damper to the first zone as well as a bypass and upsizing ducts to the addition could solve the problem.

Would take an on-site evaluation by a pro to determine what's viable.

Ideally furnace/ac or heatpump should be 2-stage but single stage can be made to work.

This is a 29y gas furnace with a 15y old AC. Senile does not even begin to describe the equipment.
You show me one system that has not been botched one way or another I'll buy you a beer. I had the upstairs and downstairs systems interconnected with a 6in duct!!!! Awesome, when up calls for cool and down for hot guess what, money just vanishes. Not to mention the pressure increase or condensation or any of the problems I have not thought of.
All the runs are strewn about, not properly, or at all, secured, bends too sharp, 135 degree or more bends, extra ducts "added" without a wye, literally cut into the side of the duct, shoved inside and then taped all over. I'm not sure I should continue. What I did in the new space was easily "the best" this house has seen. It's probably the only, properly, done run. Best I could and wanted to do under the circumstances and I do not plan to alter it by:
1. Installing a new distro box and moving all the Zone 1 runs to that.
2. Installing a 14in damper between existing and new distro box to create a true zone.
3. Installing a bypass damper to handle the excess air when only Zone 2 calls.

What I will do is boost the air speed for that run just enough. When a new hvac system is installed THEN I will properly size/zone it, not before.

Once again, I do not wish to sound annoyed or ungrateful but all I need to know is an answer to, or guidance on, whether my understanding on how I should wire this FCC is correct.

Thank you.

 

[user_12345a]

What you want to do simply will not work, yet you're set on it.

It takes a really messed up duct system for a full area of the house to not get sufficient heating/cooling despite being zoned.

Putting a damper on the the second zone and actually offering to add zoning to a existing duct system with a 29 year old furnace -> that really speaks volumes.

There's a whole science to this stuff and it sounds like you did the work yourself without doing sufficient research.

I would call a contractor to get rid of the 29 year old furnace, get a 2-stage unit that can run on low fire when only one zone calling and get the zoning/ducts fixed. (calculations need to be done first to know what to do with the air ducts.

But you just want a cheap and quick fix that won't work - if the job was done right to begin with you wouldn't be in this mess.

There are threads like this here all the time - it's a shame because trying to help is a total waste of time.

Goodbye.

 

[yonkoc]

Goodbye.

Never thought I’d visit a website to look for help, asking a very specific question, to then get slammed repeatedly for even trying to get help. I’m sorry, I don’t think I have to explain why or how I came to the booster fan solution, nor should I be put down, again, repeatedly if I want to bash my head against the proverbial wall. You should have responded, assuming you were knowledgeable on wiring an fcc, “Here’s how, but you should get someone to help you with the whole system.” Assuming I wanted to get someone I might have. You handled this query very poorly. Very. I shall close my account here, couldn’t care less if I got an answer now.

 

[beenthere]

What would happen is that when the zone 2 thermostat stopped calling for heat. The damper would close, and the furnace blower would still be running, blowing heat into zone 2.



This is something to be considered before saying if it is doable or not.