Tankless Water Heater Troubles

[ddickey]

Using this water heater for my infloor heat in my shop. http://www.takagi.com/products/tankless-water-heaters/t-h3m-dv-n
the thing is clogging up quite a bit. Not sure if it excess flux or what but the particles look greenish blue like oxidized copper would look.
Also the heater is squealing and squawking exactly like this. Start @ 1:40.

I tried changing the altitude setting and the length of my exhaust/intake and nothing helps.
Any suggestions?

P.S. I called tech support and they said I was using to much glycol causing the water to boil, huh?

 

[RJSakowski]

Firstly, adding ethylene glycol raises the boiling point which would decrease the tendency to boil.

My parents L.P. furnace would sing like that when it was first turned on. As it warmed up, the noise would go away. It was caused by a loose combustion tube. As the tube warmed, it would expand and the vibration went away. Your boiler is far more sophisticated than my parents 1950's furnace but I suspect that a similar thing is happening.

 

[ddickey]

That would make sense because as you increase the heat output the groaning increases. I also wonder how much air is in the system. I have an air separator/eliminator but...
Had the clean the filter twice today, although the strainer (separate component) is clean.

 

[RJSakowski]

You can check to see if it is copper by dissolving some of the sediment in muriatic acid. If you then add to some ammonia solution, it will turn a deep blue color.

 

[Dhal22]

Let me think here. I'm a master plumber, should have some ideas for you. Rereading your posts now.

 

[Dhal22]

Are you regularly rescaling your heater?

 

[Dhal22]

What about flushing the entire loop(s)?

 

[MontanaLon]

That is a fan forced vent system, it sounds like the fan is hitting something or causing a harmonic.

 

[ddickey]

@Dhal22 Do you mean descaling? No, I just installed the system. I was going to try doing that today. This is the Glycol I use(d),

Hercules® Cryo-Tek™ - 100 Antifreeze | Oatey

Hercules® Cryo-Tek™ 30 gal -100 Antifreeze is a ready to use 55% Virgin Propylene Glycol formula. It's designed for hydronic heating and cooling closed loop systems, most solar heating systems, snow melts, radiant heat and general plumbing systems. Behold the power of Hercules®, products built...

www.oatey.com

When I filled the system I used 5 gallons and the rest ~8 gallons distilled water.
@MontanaLon Fan forced vent? I'm not sure but yes there is a fan for combustion air. Not hitting anything but yes sounds like a harmonic but...Yesterday after cleaning the filter I started up the system and ran the pump on fast speed ~2gpm at full temp 120°F and it ran perfectly after about 10-15 minutes it start to squeal again so I lowered the temp and speed seemed to help.

 

[NC Rick]

I have the same brand tankless for our house hot water. It's been installed for well over ten years. No issues but yes it has a fan forced exhaust which I need for the 30ft horizontal exhaust across the shop. I think it is 130,000 btu but is variable. Cant add much.