Tankless Water Heater Troubles

I can't give specific advice but that filter is a little concerning. I am assuming that filter is in the unit to filter any debris within the loops? Mine (different brand) has a separate filter canister that the water/glycol mixture goes through. That filter is maybe 2.5"x10".
I read through some of the posts on that YouTube video and as one person mentioned, it sure sounds like cavitation. Maybe one of the pumps is cavitating and sending the sound into the unit. Or, the cavitation bubbles are reaching the heat exchanger causing that sound. I'm afraid that I don't have a good answer for you.
 
Based upon that filter screen, I would love to flushing the system, but until you get the system stable wait. Add a larger filter external and refill later. Obviously an external filter would have to wait but that is a lot of debris that can restrict the flow! Keep cleaning it until the level of debris drops.

Funny how HVAC issues tend to happen around a holiday!
Pierre
 
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I would have no idea how to add a larger filter. I mean I would but I do not want to cut into the system at this point.
I only have one circulator pump in the system.
I believe I did make a mistake by putting the wye strainer on the discharge of the pump. The reason I had to do that is it was a last minute addition and I was out of room. Already thinking about redoing the design for next winter. Been reading and watching videos all morning. Saw something interesting about gas pressure. Has me thinking.
 
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Ohhhh. Interesting.
I have never seen condensation or ice on a boiler like that. What the heck. So, is the part after the wye an intake and exhaust in one? I am wondering if you have that backwards? The noise could very well be the exhaust fan developing a build-up of ice on the blades?

Edit: I just went and looked at mine and the intake is the outside, just like you have yours. You must have a really high humidity level in your shop at the moment, which I am assuming comes from the new construction.
 
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70% right now. The metal door frame is full of condensation and I noticed a couple drops on the floor yesterday just below the access panel to the ceiling. My intention was not to run it the way it is. I wanted to go straight up and elbow it outside. Because the wye (air preheater) was to long I could not do it how I originally had it planned. I suppose I could've put a 45 on and come out away from the wall then I probably would've had enough room.
 
Is that your combustion air and flue gas vent line tied together? When you burn a fuel, one of the by-products of combustion is water vapor. If the outside of that pipe is icing up, you can bet you have near solid ice plug inside.
 
Yes it is. I tried to put a slight slope so it would drain back out of the condensate line. Yes I do have ice that forms but it seems to be the exhaust more than the air intake. I do check is still open on the outside end.
 
So your trying to mix flue gas with fresh air supply, I doubt seriously if that heater was configured to run on flue gas mix. Your burner is needing a good fresh air supply with correct amount of O2, your sending it moisture laden air with carbon monoxide and going to get a poor burning, sooty flame, that generates even more carbon monoxide.
 
xr650rRider said:
So your trying to mix flue gas with fresh air supply, I doubt seriously if that heater was configured to run on flue gas mix. Your burner is needing a good fresh air supply with correct amount of O2, your sending it moisture laden air with carbon monoxide and going to get a poor burning, sooty flame, that generates even more carbon monoxide.
Click to expand...

No. That is not how that system works at all. It is a pipe within a pipe. That is a common system configuration. There is no mixing of gases.
 
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