Office and warehouse in both Crystal River & New Port Richey ,FL
Originally Posted by perrybucsdad
Thanks Dash.... I'll make sure someone does a static pressure test then. Does every contractor do them? From looking at this site it looks like some do and some don't. From what you said it would indicate to me that this would tell the contractor if the ductwork is adequate or not. Maybe that is an oversimplified explanation, but that's what I am getting from your post.
Static pressure .taken correctly,along with the manufacturer's "fan Data chart" information used correctly will give you the cfms for the motor speed it was running on at the time it was taken,
Good idea to have the fan data there when the test,so they can change the speed if needed and retest.
BTW, the furnace is a Whirlpool 90+ Gas Furnace (Thought I had the model on here but I do not), and the outside compressor is w Whirlpool WC136A-1A. I tried looking on the Whirlpool website for that model of the compressor and they do not list it anywhere. That's scary.
Beenthere... actually, I found it online. It was in a document that they did not leave (just like the compressor and the coil).
Now I see how important the static pressure data is. Since I don't have the exact model number to tell me more about the airflow descriptor, I can't say for certain what CFM I should be seeing, but I can see a that it can go from 2070 CFM @ .20 SP to 1570 CFM @ .90 SP. Wow!
So what exactly is static pressure? Is it how much suction or resistance the blower is having to overcome on the return air side?
One thing I tried last night was to see if the main cover over the bower would get sucked back to the unit if I tried to remove it. When I removed it, it did not want to come off the unit with the blower running. I ran it without the cover for some time last night and I could notice a marked improvement in air output in the far room. Not blasting air, but still a good breeze compared to what we had seen. I think that would tell me that there is an air delivery problem.
One other thing I noticed while running it this way, was that the door to the basement behaved strangely. Normally, I can sort of close the door so that it is just cracked and it would stay that way. While I had it running with the cover off, the door would open at a medium speed. Is this part of that static pressure?
Well, anyhow, I placed a call this morning to a different HVAC contractor who is going to come out this afternoon to take a look at it. He said he would perform a static pressure test for me, which is good. My neighbor (who is not an HVAC guy) said he had the equipment to do it, but when he said he would be drilling into my furnace, I told him I would rather wait for a professional to do it. I understand that you need to drill into it, but I would feel quite a bit more comfortable if a pro did it.
The static pressure is a measurement of resistance that the blower is working against in both the return and supply. Although they are measured seperately, they are added together to get the total static pressure.
Yours could be more then .9"
The contractor can get the model number of your unit, and you may be able to find the correct chart for your unit online then.
Could it be resistance in the supply lines? Maybe the trunk is too small?
I took a look at my neighbors system last night (different builder and very efficient). His house he can drop the temp fairly quickly. His supply and return lines looked very simple. None of his dampers were engaged and he had nice and strong delivery in all rooms.
Mine on the other hand takes all kinds of turns etc.
I also just talked with my builder this AM. I was surprised that he said he would get a contractor out there to fix it. He mentioned something about adding fans to the supply lines to help push the air to the farther rooms. From reading on this site, it sounds like most of you do not favor that. And if in fact my static pressure is quite high, I would think there has to be a way to decrease it which would help with my utility bills (my electric bill is almost twice what my neighbors is and he keeps his house cooler than I do).
Since I brought this up during my homeowners warranty period, and the builder said he would fix it, am I within my right to demand that a certain static pressure (within reason) be archived? If so, what should my target be?
Last edited by perrybucsdad; 06-12-2008 at 10:29 AM.