Balancing a vanEE HRV

[gmacfarlane]

Hi all, I need advice from people who do this for a living. I am not in this trade but have 3 trades to my credit so am not a total dunce. I am trying to get my HRV working properly, I don't believe it ever has, and now 16 years after my house was built, I am trying to resolve some issues. The HRV unit I have is a vanEE 190H, the wall controls are 20 minute pushbutton timers and the main wall control is what vanEE calls bronze. I pulled all the filters and cleaned the core last week. I also walked the piping route and discovered that the HRV is tied into my cold air return on my furnace (UX080R942W). I understand that this type of installation that the furnace fan needs to run whenever the HRV is operating. The installer never told me this and I don't believe that the 2 are interlocked. I need to trace some wires as the HRV control drawing shows 2 wires and I have 5 connected. I will figure that out but my problem today is balancing. I bought a magnehelic gauge of the range specified in the manual (0-.5"H20). I do not seem to have enough range to match the manual. On the fresh air flow I have .32"/H20 and on the exhaust I get .12"/H20. Metering butterflies wide open. I can reduce the fresh air to .2 with the butterfly closed. Obviously it can't be closed. I have checked the intake and exhaust vents and they are clear. I also tried turning the furnace fan off and on, no difference in my readings. I think I have initial installation errors at play here but am frankly lost, where should I start. I realize it is hard for someone to trouble shoot this from a distance but I need to start somewhere before I call a pro in. Also, when I get to the interlock aspect, which fan speed should I be tapping into? My furnace has 4 speeds. Any advice will be much appreciated!

[Admin]

That makes sense you have 5 wires.  3 wires for the timers and 2 for the main control.  You should use the 3 wire interlock method and install a 3 wire between the HRV and furnace.  You will break the G connection so the HRV will energize whatever fan speed comes on when you turn the thermostat fan to ON.  You could also replace the thermostat with an Ecobee and use the 2 HRV main control wires and connect them to Ecobee ACC terminals and then the thermostat would activate the fan and HRV and you wouldn't have to install a new 3 wire for the interlock.

Are both indoor duct connections connected to the return?  The fresh air to building should be at least 10' from the furnace and then the stale air from building at least 3' past that.

Don't try to balance the numbers on the tool using " wc only.  To match the CFM ont he intake and exhaust the " wc will be alot different.  You have to look on the HRV for a sticker and it will give you the proper CFM number.

[gmacfarlane]

Only the fresh air in is connected to the furnace cold air return. The intake on the HRV has vents all through the house, I have the 10' and 3' minimums as you suggest. How do I balance the system using the cfm chart? It is on the side of the HRV, I just don't know how to read it properly. I have a wi-fi Honeywell thermostat (RTH8580WF). I can add the interlock relay as long as everything else I have is compatible, this is where I need advice, I really do not know. I can read schematics and follow instructions but I do not have any background in this!

[Admin]

Sorry I forgot you had timers and a dedicated system so that duct work connection sounds right.

Post a picture of that sticker on the HRV with the CFM numbers.

Does the installation manual mention needing an additional relay? Sometimes the interlock terminals are already part of the HRV.  Look for C, NC and NO terminals.

[gmacfarlane]

Please see attached, yes, the manual calls for an interlock relay which I am sourcing.

[Admin]

On the fresh air flow I have .32"/H20 and on the exhaust I get .12"/H20.

.32 fresh = 165 CFM
.12 stale = 166 CFM

That HRV seems to be balanced perfectly.

[gmacfarlane]

Well, clearly I don't know how to read the charts but you do! Thank you so much for helping me with this!