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Trouble with Bryant aluminum boiler.

stall3 Member Posts: 1
Thanks for reading. I need advice on this boiler I looked at yesterday. I'm a tech for a company that installs mostly forced air. I install 2-3 boilers a month. Anyways...
Called out to a boiler yesterday for noise issue. Series Q90-100. Model bw9aan000100aaaa. Which I found out later is a Bryant/Carrier. The boiler goes through its cycle draft inducer and pump sound good. Igniter glows. Soon as it ignites makes a high pitched squeal. Can't pinpoint it so cycle it few times with same results. Want to start with the simple, check propane tank. Half full. Check incoming pressure 10.64 " w.c. Notice no sticker that it's been changed to propane. Manifold pressure reading 3.3 wc. Home owner finds the manual eventually. Combustion analyzer reads High CO after a minute in the flue. I'm reading the manual and looking over the system for a little bit. Talking with customer, who has to ask me what I'm doing every time I breath. Been running great since it was installed six years ago, until a couple weeks ago when the noise started. This boiler has never been serviced. And the man who put it in hasn't returned his phone call. ( unbelievable!) So I'm checking it over, the 1/2" condensate line if the bottom of the exhaust is full and the condensate pump is dry. I took apart the condensate lines, the exhaust goes back in to the boiler and tees in with the line coming off the bottom of the boiler and goes to a contraption of a barb fitting threaded into 1/2" pic, which runs to the cond pump. I guess this is what the manual was calling the trap, but the manual wasn't helpful for me as far as that. I blew the hoses, got some junk out of the pvc, flushed with water.

My first concern is that when I pulled the cond tubing from the bottom of the boiler it was plugged and I blew out what I will describe as a substance that looks like mastic. (Aluminum putty- like substance). I hope this doesn't seem like complete ignorance, my only experience with alum hx is Buderus gb142. Never seen this before. So, what is this, and is there any cause for alarm?

So, put it all back together. Next, ohm igniter. Reads 135 ohms. Seems to be a high resistance, but again the trouble shooting in this manual is little or no help.
Must say that I see no way to access the heat exchanger. I can look where I took out the igniter, but can't really see anything. There is a door next to that with a sight glass. 2"x3" maybe. Customers sure that I don't need to look in there, so move on for the time being. The hx appears to be two halves bolted together. At this point I'm saying that I'm not going to gain access to the hx without being sure how to. Also having no maintenance kit for this boiler, no parts or gaskets or anything if something goes south. There may be a way behind the draft inducer, which if I'm facing the boiler, is mounted on the lower right of the hx in a horizontal position. Again, I'll need some better information so moving on for now.

The fresh air intake exits the boiler panel and terminates with 2" pvc 90 facing down. Not to the outside! (All Air for combustion is taken directly from outside atmosphere... Combustion air and vent pipe connections must terminate together in the same atmospheric pressure zone.) This basement is the customers work area. Does painting and diy type stuff mostly. He says that he's a busy guy but maybe one day he'll pipe it to the outside. Fresh air goes to an air/gas mixer, attached with a 2" fernco. Inside the fernco is a screen that is mostly plugged with dirt. The reason for the noise complaint.?
Ok. Found the empty package that the propane orifice came in. Manifold pressure should be set at 2.5" w.c. Same as natural gas. I've heard of boilers that use the same operating pressure for both propane and ng, this was the first that I've worked on. Ready to turn boiler on at that point. adjusting the manifold pressure took a while. I didn't put the pressure regulator adjustment cap on while adjusting, reading only around 1" wc. Oops. I had called the boss to have a new gas valve brought to me. Read the book some more. Got manifold set properly, with the adjustment cap in place, 2.55 wc. Boiler then ran, no noise. All right. (Secretary had delivered the wrong gas valve- only one on the shelf). Put my analyzer back in the flue and start cleaning up. Well, I must have damaged my analyzer with the High co earlier. Wouldn't read co, but read 7.0 for o2 and 8.1 co2. So I'm thinking I'll get some better information on how to service this Bryant and come back next week. Or better yet, have him get the installer, or maybe someone that is more familiar with this system than myself.
Boiler hit high limit, so I wait for the next cycle. Draft inducer comes on and pressure switch not making. Now what? Another hour checking the hoses and ports, been there 3 hours now. Somewhere in there I had jumpered the pressure switch to make it run. I remembered this when I was 10 miles down the road. So I go back and of course, it was locked out- pressure switch closed on trial for ignition. Put the wires back. Tries to light. Nothing. Another hour, thinking, answering a hundred more questions, looking. At that point I'm beyond frustrated. Now when the gas valve opens and it tries to ignite the flame pulsates three times and the control starts a recycle. Has 3 seconds to prove flame. Ignition problems again. Propane or air right? I've left the basement doors open the whole time, trying to make sure there's fresh air. I put my manometer back on the manifold and as it tries to ignite/ pulsates I read only about 1.5" wc. Back to the gas valve? Or am I missing something simple? It was 7:30 already. The customer is anxious, has plans to take his wife out. He will use the fireplace for tonight and deal with no hot water. I'm upset I've had no success. Add to that I can't tell the boss I'd been there for five hours. I won't get paid for the last 3 hours. Oh well. I may have to go back there on a Saturday, hour drive each way, not get paid for that. No big deal. But what's really going on in my mind then was something I've read dozens of times on The Wall. And that is you guys saying: shut it down and call a qualified technician. Hmmm.
Am I doing something wrong? Lack of experience maybe?
Should I be expected to work on every types of system out there? Systems that I'm not familiar or comfortable with?
When do I walk away, knowing that no one else will return the homeowners calls? Now I'm assuming he found someone else, as he didn't return my calls Saturday
Been at this all night, and it's Sunday morning. Happy Easter.
Thanks for reading. I look forward to any comments, suggestions or criticism. Anything that I can learn from.


  • Zman
    Zman Member Posts: 7,573
    Can you post the manual for the boiler? A quick search only shows a dunkirk stainless model.

    Does your analyzer read CO when it is not in the vent? The CO may be over the max your instrument can read.

    It sure sounds like the heat exchanger is in need of cleaning.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • unclejohn
    unclejohn Member Posts: 1,833
    I need more info from you.
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
    edited April 2018
    First of all, you take analyzer reading when the boiler is at operating temperature. Your analyzer is set to propane, right? I've made that mistake, but only once.

    As Zman says, are you sure it isn't s Dunkirk boiler?

    I would use a inspection tv camera and look in the HX where the hot surface ignitor came out and look for any water marks or other adnormalities in the HX.

    If it has a rectifier probe be sure and clean it, don't use emery cloth, use wet or dry sandpaper or a small stainless wire wheel brush on a Dremel tool.

    If the HX is cleanable, it may need cleaning, along with the condensate drain.

    A high pitched noise coming from the HX indicate an improper combustion setup. Gas valves do wear and combustion metrics do change. You need a recently calibrated combustion analyzer and the manufacturers specs as to combustion. 8.1 for CO2 seems on the low side to me, indicating that the CO is high.

    What does the manual say the manufacturer is?
  • kcopp
    kcopp Member Posts: 4,441
    It is an ECR boiler... Dunkirk, Utica, Bryant... same block... different stickers.
  • ch4man
    ch4man Member Posts: 296
    that aluminum looking sludge is just that, aluminum. it used to be the heat exchanger. aluminum dunkirks are not high on my list

    you'll need the gasket, but there is an access panel on the opposite side of the block from the inducer. you'll also find more sludge in the bowl that makes up the inducer housing. you need another gasket for that as well.

    all this is due to lack of maintainace on the part of the homeowner. it all should be billable ( sorry, i do feel for the HO but...) so maybe your boss should pay you for the whole job
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
    Water quality in aluminum HX is extremely important. It sound like this boiler has been neglected. You're probably going to have to flush the system and start from first base. Clean the HX, follow manufacturer instruction as to water quality and flush and fill the system. Then do a combustion analysis with a recently calibrated meter and set the combustion to the manufacturer specs. Only then look at other problems.

    Explain to the HO you either pay now to fix it or pay later for a new boiler.