Sunday, December 19, 2010

Duke Comes Through (Sort of...)

A couple weeks ago, our good friend Duke came through and fixed the problems with the HRV venting... sort of. In the front, he cut a new vent, which is supposed to be for the HRV exhaust, below the attic vent. He hadn't switched the actual ducts yet, so the intake duct was connected to the new vent rather than the exhaust, but he knew about the problem and was planning on switching the ducts around when he came back to install the fitting on the condensate drain. Apparently, Fantech forgot to ship a condensate drain fitting along with the HRV unit. Duke ordered it, it was supposed to be here that Fri. Unfortunately, our good friend Duke is lacking in, shall we say, aesthetic sense. The concept of "curb appeal" is lost on him. Consequently, the front of our house now looks like this:
The new duct is about 3 inches lower than the old one, instead of nicely aligned. Rather than try to fix the problem, which would involve filling in the hole, we're simply going to paint the ducts the same color as the house and leave it at that. They should blend in enough with the house that they won't be all that visible. We also needed an electrical outlet to plug the front HRV in, but that's the electrician's job. He was supposed to install it that week.

Speaking of aesthetic issues, the HVRs require piping to drain off any condensate that might occur on the heat exchanger. The missing fitting is what was holding up the front HRV. Since the HRVs are installed in attic areas without any plumbing, there needs to be some way to get the water out of the HRV and drained away. Here's what our back condensate piping looks like:
The white pipe coming out through the wall is the condensate drain. You can also see the solar panel for one of our solar garden pumps near the top. This white pipe doesn't look so nice either, and will ultimately be painted. The pipe is unfortunately PVC. PVC is not a particularly environmentally friendly material. I asked  Paul why they couldn't use ABS pipe instead, but ABS doesn't come in the 1/4" diameter stock that is needed for this application.

On the back, we now have a veritable proliferation of hoods:
Only the one on the lower right and upper left will ultimately stay. The others will disappear when the siding is replaced in the triangle on the right side of the picture. Then they will recut the vent on the lower right, which will be an attic vent. The upper left vent is the HRV intake. The HRV exhaust has moved to the roof:
It should be the tall one, the small one is the bathroom (high speed) exhaust. Below you can see how Duke rerouted the bathroom exhaust duct out the roof:
It is the hard, elbow-shaped pipe running up  the middle of the picture. The exhaust is the soft duct on the upper left.


As they came from Fantech, the SH704s have no low voltage switch. You just plug them in and they start up. I'm not sure what Fantech had in mind as far as control. A Web search turned up the Aubetech 1702-3W which is a three wire, high voltage (i.e. 110V), 7 day timer switch with maximum 2 settings per day. I ordered and received 2  Aubetechs for the HRVs. They are rated for up to 1 HP motors, the Fantech motors are less so there should be no problem. This will allow the HRVs to turn off during the day when we are at work, and on again in the afternoon. The electrician needs to wire them up yet. We are going to put them into the closets in the bedrooms nearest the HRV units, so they are not visible from the room.

I also started the HRV above the master bedroom and, to my surprise, there was no problem with vibration at all. While the actual HRV unit itself vibrated due to the fan motor, the vibrations were not transmitted through the shock absorbers to the house frame. There was a very faint noise in the downstairs bedroom, about what we hear when the solar thermal pump goes on, which I assume was from vibrations transmitted through the air to the ceiling. With closed cell foam in the ceiling and additional soundproofing, I think the noise level should be OK.

This week, Paul, Christine, and I checked the HRVs and it seems like everything has been properly installed. The ducts are routed out the right vents, the front HRV has an outlet, and the condensate drain is in on the front HRV. The electrician still needs to install the Aubetechs yet, but he's started the wiring. All in all, it looks like our adventure with HRV installation is slowly drawing to a successful, if not entirely satisfactory (from an aesthetic standpoint) close. In a future post, I'll give a retrospective.

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