ERV Frustrations

[Trepex]

Hi All,

Running into the same frustrating issue with our ERV for the forth time now (it has happened in both winter and summer seasons). The flex pipe for the fresh air intake keeps becoming saturated with litres of water and Harding has been unable to fix it. They determined that it's not the intake itself, but water is accumulating between the flexpipe and the outer plastic that seals the insulation around the pipe. First thought was condensation, but it's such a massive amount of water that it seems it would have to be a pretty significant hole somewhere to allow that amount of warm air into the insulated area of the pipe.

Each time Harding has come to repair the issue, they've cut open the plastic barrier on the pipe, and the insulation has been soaked, water comes pouring out, etc. They replace the line and we have the same problem again. They claim that it's really well sealed at the vent side and tied in to the rest of the vapour barrier at the wall, and then at the unit it seems to be clamped properly.

The water always seems to accumulate in the lowest dip of the run. Odd however, as it really doesn't seem to be water coming from outdoors...

I'd thought of simply having the run replaced with rigid insulated pipe - would that be a good idea? I doubt Harding will do it, but I could just do the damned work myself if it would solve the problem.
Final note, because several who I've spoken to have asked: This is an ERV and not an HRV, so I don't have a drain line, and water shouldn't collect in the unit. Really, any humidity should be exchanged from one side to the other, and so there shouldn't be an accumulation in the unit. If I thought that it was the intake itself that was leaking with water coming in from outdoors, I'd believe that maybe water was coming in and pooling in the line, then perhaps leaking through a tear into the insulation. Doesn't seem to be the case.

Any advice?

[Mark & Lynda]

What brand is the unit?

Interesting that you say you do not have a drain line. I have an ERV and I still have a condensate line from the ERV.

Not sure if this would be the cause, but, was the unit balanced?

[Trepex]

Originally Posted by Mark & Lynda

What brand is the unit?

Interesting that you say you do not have a drain line. I have an ERV and I still have a condensate line from the ERV.

Not sure if this would be the cause, but, was the unit balanced?

It's a Venmar Duo 1.9. Interesting about the condensate line... There doesn't even appear to be a place for it, unlike the obvious hook-up on the HRVs that I've seen.

EDIT: I've found a couple of posts that seem to suggest that many ERVs don't require a condensation drain because they "transfer water vapor better than others, especially ERV’s, [and] they don't produce condensation (copy-pasted instead of referencing another forum)

[Trepex]

Originally Posted by Mark & Lynda

What brand is the unit?

Interesting that you say you do not have a drain line. I have an ERV and I still have a condensate line from the ERV.

Not sure if this would be the cause, but, was the unit balanced?

And sorry, forgot to mention - there is a sticker on the unit claiming it was balanced shortly before our occupancy date.

[Mark & Lynda]

Mine must have the drain line because I can convert the core to an HRV. I have a Vanee 2001 ERV.

Are you running the ERV and your furnace fan together and 24/7?

[good2know]

condensation on the exterior of the pipe would saturate the insulation

have they replaced the pipe and insulation when they have come?

[Trepex]

Well, the flex pipe and insulation come together. You can see from the attached pics. In the one photo you can see where the cut the outer plastic sheathing to expose the insulation and flex pipe inside. The first time they replaced the entire run, and they blamed a bad seal at the vent cap outside. The second time same thing. The third time he wasn't sure of the problem, but just cut out the bad part and then presumably reattached the pipe and then the sheathing. The last time he did strap the duct up nice and tight, and the lowest dip moved to the point which now most recently leaked. I'm wondering if this last time he just did a bad job of sealing things back up properly where he patched the duct. Seems to stupid to have not just replaced the entire run.

They're coming back out again on Jan 5th to replace the flex duct AGAIN, but I'm really not that confident they can solve it. Maybe they aren't tying in well enough to the vapour barrier on the wall, with the outer sheathing? Or maybe not sealing properly at the unit? But then again, that wouldn't cause the water to pool further up-stream... Then there's the fact that the builder did such a crappy job with vapour barrier in the basement anyway that the moisture could just be getting in behind there anyway and then into the pipe.

Am I just dealing with guys who have no clue how to properly do this installation?

[waikiki]

Have you seen how the connection runs through the OSB wall to the outside?

Our connections were not properly done since the hole was cut square and the sides left open with barely tuck tape around so we had water in the basement. It's not obvious from outside unless they remove the square cover and check the seal around the duct work (behind your siding/brick). I pulled the insulation from the inside and with the unit off I could feel air coming in so I knew we had more issues.

I would ask them to show you the seal from outside AND inside to make sure. And take pictures.

[good2know]

trepex your installation manual shows very specific details on how the ends should be connected - show the techs that and ask that it be installed that way.

this is a mystery to me - if there are no holes in the pipe and no cuts in the plastic wrapper, then you shouldn't be getting huge moisture buildup

I've never had this problem in multiple properties over many years ??

[Trepex]

Originally Posted by waikiki

Have you seen how the connection runs through the OSB wall to the outside?

Our connections were not properly done since the hole was cut square and the sides left open with barely tuck tape around so we had water in the basement. It's not obvious from outside unless they remove the square cover and check the seal around the duct work (behind your siding/brick). I pulled the insulation from the inside and with the unit off I could feel air coming in so I knew we had more issues.

I would ask them to show you the seal from outside AND inside to make sure. And take pictures.

Good point. I suppose I could sprayfoam the hole if it's not a nice tight seal there. Not sure how well I can do that to seal around the flex pipe in the area where it connects to the vent cap though.

Originally Posted by good2know

trepex your installation manual shows very specific details on how the ends should be connected - show the techs that and ask that it be installed that way.

this is a mystery to me - if there are no holes in the pipe and no cuts in the plastic wrapper, then you shouldn't be getting huge moisture buildup

I've never had this problem in multiple properties over many years ??

Interesting. Is this installation guide something that I can find online? I have the maintenance manual but I'm quite sure I don't have an installation manual. I'll look through literature on Venmar's site to see if I can find it. I did find the following, which goes into details about how to properly terminate the flex duct:
http://healthandenergy.com/installin...ventilator.htm

EDIT: Found the manual here. Thanks for the suggestion. Will give it a read.