Vaillant F70-55 boiler strange metal thing??


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Old 11-05-09, 09:48 AM
J
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Question Vaillant F70-55 boiler strange metal thing??

I have a good running Vaillent F70-55 oil fired boiler.
during this fall service this 12" light metal thing with
a 4" hook with 3 3"x2" swinging plates attached was
found lying in the bottom of the combustion chamber.
The tech did not have a clue. Does anyone know what
this thing is and were it might go.

Thanks jo34jo
 
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Old 11-05-09, 11:28 AM
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Sounds like a cover plate for something , could have been their since installation , but maybe not , ive heard of faulty compressors sent back to factory and found a quarter in them , no way to get one in cept when being made .

But surly he would have known where it would have gone:Homer:
 
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Old 11-05-09, 02:54 PM
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I can tell you exactly what that thing is, and if your tech didn't have a clue, he did not clean the flue passages in the boiler properly.

That part is a 'flue baffle'. It is designed to hang in the flue passage and create 'turbulence' in the hot gases as they pass through the boiler in order to better transmit the heat to the cast iron.

I believe your boiler is a 5 section job, and there would be 4 flue passes vertically on either side of the chamber. Each flue pass has one of these hanging in it.

On the top of your boiler block, underneath the top cover (which lifts off) there is a layer of insulation. Under that insulation is the cast iron 'block'. There are metal plates, about 2" x 4" sitting on top with a gasket underneath them, and held in place by metal spring clips wedged under the 'stay rods' that bolt the block together.

To properly clean the flue passes, these plates are to be removed, along with the gasket (which will probably need to be replaced) the baffles lifted out, and the flue passes brushed out.

These boilers are a royal PITA to clean properly... and since Vaillant doesn't market in the US anymore, most techs have never seen one. I'm willing to bet that yours has never been properly cleaned, and you probably have several of the flue passes plugged up. I'm also willing to bet that if the tech didn't know about those clean out ports, he also didn't properly clean the upper heat exchanger chamber. That's even more of a PITA to get to... I won't go into it... but, if he even brought a vacuum cleaner out of the truck and vacuumed out he combustion chamber, you're one of the lucky ones.
 
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Old 11-06-09, 07:08 AM
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NJ Trooper, You get a A+! Called Vaillent, talked to a
very nice gentleman who knew it all. He stated that
they were used to up the efficiency by a small amount.
And in some installed cases they were causing too
much back pressure and had to be removed. He also
said if my boiler was running above 80% (mine 81%) it
could remain out.
The Tech always clean the upper heat exchanger chamber,
along with the combustion chamber. I've seen him do it,
but the flue passes??

The boiler works good, but getting older. Might need to
consider, next summer a replacement.
Any suggestions on a newer boiler? Kinda want to stay
away super efficient type.

Thanks again
 
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Old 11-06-09, 02:14 PM
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I guess leaving ONE out wouldn't hurt a thing... I do know that one time I accidentally left them ALL out, and my flue gas temp went up to something like 550... normally runs around 400-450... and that makes sense for the combustion efficiency, cuz the higher the flue gas temp, the lower the efficiency... in general.

Amazing that you found someone at Vaillant to talk to!

In the standard-mid efficiency class, I would recommend the Burnham MPO hands down.
 
 

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