Page 1 of 2 12 LastLast
Results 1 to 13 of 16

Thread: HRV balance

  1. #1

    HRV balance

    Hi,
    I just had an HRV installed, but I'm concerned that my installer did not balance it correctly. On the HRV there are ports on the bottom to use for balancing. The technician used a meter to make differential measurements on the stale air in vs out and the fresh air in vs out. He adjusted dampers to make sure the differential pressure readings were the same. I'm concerned because there is a table stuck to the bottom of the unit that shows that a given pressure reading corresponds to different CFM values, depending on whether the measurement is from stale air or fresh air. For example, a pressure reading of 0.22 corresponds to a fresh air CFM of 54 and a stale air CFM of 122.

    Is he supposed to balance the differential pressure readings or should he use the table to convert the differential pressure readings to CFM to ensure that the stale and fresh air CFM values are equal?

  2. #2
    Can anyone help? I don't have the knowledge to know for sure whether or not my system is balanced and I don't know where else to turn. I just need to know whether the installer needs to balance CFM or differential pressure readings.

  3. #3
    Join Date
    Dec 2008
    Location
    NW Washington
    Posts
    53
    Quote Originally Posted by mdesjardine View Post
    Can anyone help? I don't have the knowledge to know for sure whether or not my system is balanced and I don't know where else to turn. I just need to know whether the installer needs to balance CFM or differential pressure readings.
    How do you know he did not balance it?

  4. #4
    I was with them when they tried to balance it, but I suspect they did it wrong. I suspect this because they did not use the table on the HRV to convert stale or fresh air pressure readings to CFM. They only matched pressure readings. For example, I think that on one speed they measured .12 in. wg on stale and .12 in. wg on fresh. If you use the table, this means 30 CFM fresh and 77 CFM stale.

  5. #5
    Join Date
    Dec 2008
    Location
    NW Washington
    Posts
    53
    Quote Originally Posted by mdesjardine View Post
    I was with them when they tried to balance it, but I suspect they did it wrong. I suspect this because they did not use the table on the HRV to convert stale or fresh air pressure readings to CFM. They only matched pressure readings. For example, I think that on one speed they measured .12 in. wg on stale and .12 in. wg on fresh. If you use the table, this means 30 CFM fresh and 77 CFM stale.
    Im not familiar with the table your looking at, but if you think there readings are not correct, call them and ask them about it .. ask them to re-do there balance.. ask for a report for your records.

  6. #6
    Well, I did ask them to redo it, but the guy wasn't helpful. I don't think he really understood what I was saying. A report would be a good idea. But, am I correct in thinking that the goal of the balance is match the fresh air and stale air CFM?

  7. #7
    Join Date
    Dec 2008
    Location
    NW Washington
    Posts
    53
    Quote Originally Posted by mdesjardine View Post
    Well, I did ask them to redo it, but the guy wasn't helpful. I don't think he really understood what I was saying. A report would be a good idea. But, am I correct in thinking that the goal of the balance is match the fresh air and stale air CFM?
    If it was my HRV unit I would balance it for a positive pressure in the home. A negative home would draw cold/hot dirty air into the home. Getting a true balance would be hard...considering dirty filters and all over time. IMO

  8. #8
    I would agree that positive pressure would be better than negative, and this is my worry. If I understand the purpose of the balancing table on the bottom of the HRV, this means that I have 30 CFM fresh and 77 CFM stale which I would think would have to give me a big negative overall pressure in the house. I've attached an image of the table from the bottom of the HRV.
    Attached Images Attached Images  

  9. #9
    BUMP. Can my HRV be balanced if the installer just matched differential pressure readings from the built-in measurement ports (not flow collars) and did not use the balancing chart attached to the HRV that I previously posted?

  10. #10
    Join Date
    Jun 2008
    Location
    Southeast Michigan
    Posts
    54
    What did the instruction manual say?

  11. #11
    Quote Originally Posted by Corpsie View Post
    What did the instruction manual say?
    Thanks for taking the time to help me out. I've scanned the instruction manual and attached it to this post.
    Attached Images Attached Images

  12. #12
    Join Date
    Jun 2008
    Location
    Southeast Michigan
    Posts
    54
    I'll second the vote to call the installer back requiring him to show you what flow rate the system is set for and the pressure he measured at each tap.

  13. #13
    Join Date
    Nov 2008
    Posts
    1,673
    And when I had a door installed the guy used the installation instructions for a hand towel. And, according to the manuf., they did it wrong.

    If the installer can't make a plausible argument for his adjustment method, call the manuf. They have an interest in satisfied customers and keeping a good reputation for their products.
    Find out what symptoms you would experience for improper installation/adjustment.

Page 1 of 2 12 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event