Orange Powder and Flakes Accumulating in Veissmann Vitorond 100 Oil Boiler Combustion Area

DinoRoberti

A significant amount of orange powder and flakes is accumulating in the combustion area. It appears that the cast iron is deteriorating. There are no signs of condensation occurring in the heat exchanger above the combustion area. Will this lead to premature heat exchanger failure? What is causing the the cast iron to deteriorate?

SuperJ

You mentioned you didn't think you had condensation. What RWT and SWT are you running?

STEVEusaPA

Your cast iron is not deteriorating. It's the by product of condensation, moisture.
You're boilers temperature is staying below 130° too long and/or you are underfired.
You need a proper cleaning, combustion set up properly, and the condensation addressed.
Some more info like combustion numbers from last tune up, boiler make/model, and nozzle being used would help.
And a picture showing the boiler and it's controls.

DinoRoberti

The boiler setup is with a primary/secondary loop driving a six zone radiant floor below the floor tubing and indirect. The boiler has a Tekmar 260 outdoor reset that operates the boiler output temperature from 140 to 190 degrees depending on outside temperature. The boiler water return temperature is almost never below 130 degrees. Even on a cold start-up with all zones on the boiler water temperature within 10 minutes has an output temperature of 140 degrees. Normal operation with zones and indirect I rarely see a output temperature below 135 degrees. The boiler is running at 87% efficiency with a stack temperature of 350 degrees. The model is the Vitorond VR33 with a Beckett NX burner firing at 1 GPH per the manufacturer's specification.

Grallert

I don't recall if there were/are baffles that came with that boiler? I think there were. Often they get removed and tossed or hidden.

DinoRoberti

There are no baffles in the combustion area when installed new. There are baffles above in the heat exchanger. There is a stainless steel collar insert that the flame fires in the combustion area.

STEVEusaPA

How about some short cycling? I think I see about 5 zones. I suspect when only 1 or 2 zones are calling anytime except design days, the boiler will only run for a minute or 2.
Also is that 350° gross or net stack temperature?

DinoRoberti

Yes, there are six zones. Yes, if one zone is calling and running on time is about 2 minutes to heat the water up. The Tekmar 260 has an auto differential, so when the temperature is above 40 degrees outside the control cycles the temperature between 135 to 145 degrees. The stack temperature is gross. Basement temperature is 60 degrees.

SuperTech

I would check the draft. A high draft could be the culprit. You are already running the boiler at low temperature, high draft might be cooling things further resulting in condensation.

DinoRoberti

The draft is normal. The chimney is 1 and 1/2 stories. How can you have condensation in the combustion area where the temperature of the gases are the highest and no condensation in the heat exchanger where temperatures are the lowest. Condensation occurs when you reach the dewpoint as the gases cool. The dewpoint would first occur in the areas where the gases exit the boiler.

lchmb

someone please correct me if im wrong but are the supply/return for the boiler piped backwards?

STEVEusaPA

SuperTech said:

I would check the draft. A high draft could be the culprit. You are already running the boiler at low temperature, high draft might be cooling things further resulting in condensation.

It wouldn't be high draft. Too much draft would raise the stack temperature, as well as too much excess air.
I'd guess with the net stack at @290 degrees, your condensing in the flue and chimney.

DinoRoberti

Never had any water in the clean out of the chimney and no signs of condensation on the stainless steel pipes to the chimney. Steam can be seen when the gases exit the chimney when it is cold outside.