loud HARUMMMPH when Buderus+Riello boiler tries to start

timo888

Yet another issue.



Oil Company service performed two weeks ago and the Buderus was purring nicely after the tech left. He replaced filter and nozzles in the Riello and showed me the 87.5% efficiency rating on his meter. I know the flue is clear of debris because I looked inside myself.



Now the weather has gone from last winter freezing cold snap to early spring chill. I don't think the boiler is coming on at night. I have the thermostat set at 60 now and the house temperature has been hovering around 65. As morning showers begin, and the aquastat sends the signal to heat the tank as it's getting refilled and the water temperature drops, the Buderus makes several very loud shuddering HARUMMPH sounds, a few seconds apart, before it begins burning smoothly. It takes four or five tries. At first I thought it was a loud bass from a passing car because it is very low frequency.



My theory, for what it's worth, is that the chimney (no liner yet) is full of chilly night air because the boiler has not been firing overnight; so there's not enough combustion draft available until the several failed ignition attempts have sent some puffs of warm air up the chimney and cleared the column of cold air. Plausible? The little combustion-draft-assist fan inside the Riello seems to be working, though I don't know how strong a pull it is supposed to have. The suction isn't strong enough to hold a small piece of paper against the grill opening on the rear side of the Riello.



If there were a problem with the fuel pump, it would not start burning smoothly after a few attempts, would it? It has happened several days in a row.

icesailor

HARUMMPH:

Your assessment of the problem may be right. I've never found it to be so.

If I was the tech that tuned up your equipment, and it was behaving (as you say) after I left, I would HOPE, (no, I would EXPECT) to get a call from you so I could come and fix your problem. We all make mistakes. 87.5% sounds like pretty remarkable numbers. Whenever I tried to get a CO2 number high enough to get an efficiency as high as that, I got smoke, which led to soot. And a lot of other problems. Like what you have.

Call whomever cleaned it and ask them about it.

That's MY take on your situation.

icesailor

HARUMMPH:

Your assessment of the problem may be right. I've never found it to be so.

If I was the tech that tuned up your equipment, and it was behaving (as you say) after I left, I would HOPE, (no, I would EXPECT) to get a call from you so I could come and fix your problem. We all make mistakes. 87.5% sounds like pretty remarkable numbers. Whenever I tried to get a CO2 number high enough to get an efficiency as high as that, I got smoke, which led to soot. And a lot of other problems. Like what you have.

Call whomever cleaned it and ask them about it.

That's MY take on your situation.

James Day_2

Could it be...

Could there be air getting into the oil?  Is there a leak somewhere in the line.  Just another thought.

billtwocase

that number

is about right. I would like to see more #'s though. Stack temp, excess air, smoke test, etc. Is your chimney external? There have been many posts regarding this issue. If you don't get the responses you need, look at older posts

meplumber

I would like to see the rest of the numbers too.

The rest of the combustion numbers would tell us more.  Specifically, CO2, CO, Excess Air, and Smoke.

timo888

fix...and then it's back again

The oil company sent a tech over who said it was a blocked nozzle in the Riello. He replaced the nozzle on Friday evening around dinnertime, and the unit was purring nicely before he left. He adjusted the Riello's air-duct opening, making it a smidgen more open, I'd say about 1/4" inch.



However, by Monday morning the problem was back, though not as loud. It's taking the unit two or three false tries before it starts, where before it was taking 4-5. I have another thread about the possible culprit -- sludge in the line, and how to add a second filter:



http://www.heatinghelp.com/forum-thread/136132/pre-filter-on-the-oil-supply-line



A picture there shows how the oil company installed the first filter, and I get the distinct impression it was not done according to "best practices". Someone used the phrase "I'd be embarrassed..."



Since you bring up the issue of fairness... I'm self-employed myself and though I am a perfectionist, I'm not perfect. So I judge individuals and organizations by how they own up to mistakes and fix them.



This installation appears to have a long list of things that people here consider sub-paar. Very little about it appears to have been done correctly. It seems to have been installed by a couple of hacks the heating oil company subcontracted the install to.

timo888

tech did filter-paper test

The tech back in March put a little paper in a hand pump with a nozzle he inserted into the damper and the paper came out darkened. He kept adjusting till the paper came out clean. However, the tech on Friday said it was running a little rich, and he opened up the Riello's air intake a little.



Here's the numbers from the service three weeks ago:

O2: 4.4%

CO: 22 ppm

Eff: 87.5%

CO2: 12.3%

T-STK: 327F

T-AIR: 57.3F

EA: 25.0%

CO(0): 28ppm

timo888

air in line

Thanks, I will follow up on that. I am going to have the original ball valve replaced with a Firomatic when adding a second inline spin-on filter, 10 micron. When the tech does that work, I will ask him to check for air.

Mac_R

HARUMMPH

Knowing Riello burners and how they work with Buderus boilers.  What is the mod # of the Buderus boiler?  I know Buderus was having a small problem with the G215 with a Riello burner.  What they did to resolve the issue I do not know.  Everything looks good with the efficiency numbers you posted.  It almost sounds like it has to much air.  Riellos can be really touchy when it comes to excess air.  If you post the mod # of the burner and the Riello you are using I can give you more info. 

timo888

too much air / fuel mix

All told, three different techs looked at it and each would leave with the system running, but by next morning, the problem would be back. One common thread: they all had trouble purging the pump. Not sure why. Slow leak? Foamy fuel? Not enough suction? Pump misadjusted? All of the above?



During a delayed ignition episode, I blocked the air intake 50% with my fingers and the Riello fired right up. I removed my fingers and it started harrumphing again.



So I hired a different organization to install a TigerLoop (in case there was an air problem) and to dial in the burner/pump. It has been running smoothly since then at 87.9% efficiency.



I understand that TigerLoop is now installed on all of the latest Buderus super-high-efficiency models

icesailor

Tigerloops:

A lot of Techs don't like Tigerloops.

It's quite amazing how many times they solve problems though. I've installed a tribe of them with never a sad result.

James Day_2

Tigerloop

I Install a Tigerloop on any new oil boiler that I install.  For a few bucks more it saves on hassle later.