I have a shop building with central hvac and I wanted to reduce the air flow on one side of a divider wall (about 35% of the floor space) and add flow to the other side. I figure on adding registers and maybe another run on the "warm" side. On the "cold" side, would restriction of flow at the registers be OK, or is it better to restrict the ductwork run near the plenum? Thanks Bill
Its called get a new manual D ran, and adjust accordingly. You dont just go slapping in a new run, and registers.
And normally, (ok..its rare..not everyone goes out and buys the balometer) someone that knows how to do the D will also be able to insure that the airflow at the room is what it should be...
You can do it yourself and you don't need a manual D. You have the right idea, except you may want to just increase the size of the duct to the side you want more air on. And after that you can can fine tune with restricting the air on the side you want less air in.
Pj
thanks btw, what is a manual D, a sizing calculation method? bill
Yes a manual D is a calculation method of determining Duct size. It is the right way of doing it to make sure everything will work properly and not cause future problems. I suggest you find some to do the manual D.
I will get someone to look at it. The existing equipment needs to be checked out anyway. thanks Bill
No, you don't need a manual D. Take the money you would waste on a manual D and spend it on a nice thermometer and you will be far better served. You live in the house so you can 'adjust' the air flow to get it just like you want it. Anyway, A manual D doesn't account for many of the variables that change the temperatures of various rooms. (Like my dog standing with his head stuck out the doggie door or my daughter taking a 2 hour shower with scalding water)
A Manual D does not tell you how to adjust the air flow. It provides the information so the correct duct sizes and design can be made so it may be possible to do as you suggest.
On 12/7/2004 4:39 PM US(ET), HvacTech2 took fingers to keys, and typed=20 the following:
Is a 'Manual J' the one for heat loss calcs?
Are you saying that duct size and air flow are NOT related?
No. I indicated that a Manual D does not tell you how to adjust the air flow, It provides the information so the correct duct sizes and design can be made...
You are about the dumbest smart guy I've ever seen.
In fact, duct size and air flow are inseparable.
PJ
Maybe someday you will learn to read and understand what you read. Until then, good luck
Hey Bill, Resriction of duct work anywhere is never ok! Static pressure drop is the enemy of air flow and would only increase with any kind of restriction. The duct work should simply be re-arrainged to dump more air where you need it and less air where you dont. Because or static pressure you can only put so much air so far thru a certain size pipe, thats the physics of air flow. I guarentee your duct system is not "oversized" , so, any increase in static pressure will back up all the way to the coil and actually to the blower squirell cage and decrease flow over the coil, which at 400 cfm per ton of refrigerant will decrease the total efficiency of your hvac equipment.
Hi PJx, hope you are having a nice day
On 07-Dec-04 At About 01:05:04, PJx wrote to All Subject: Re: reducing air flow in part of the floor plan
P> From: PJx
P> P> No, you don't need a manual D. Take the money you would waste on a P> manual D and spend it on a nice thermometer and you will be far P> better served. You live in the house so you can 'adjust' the air P> flow to get it just like you want it. Anyway, A manual D doesn't P> account for many of the variables that change the temperatures of P> various rooms. (Like my dog standing with his head stuck out the P> doggie door or my daughter taking a 2 hour shower with scalding P> water)
I don't think you know what a manual D is. a manual D is a duct calculation not a heat loss calculation and if he is smart he WILL get a manual D for proper air distribution.
-=> HvacTech2
Hi willshak, hope you are having a nice day
On 07-Dec-04 At About 07:09:02, willshak wrote to All Subject: Re: reducing air flow in part of the floor plan
w> From: willshak
yes.
-=> HvacTech2
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