Howling Knight

Nick S

I installed a Lochinvar Knight a couple of weeks ago that keeps howling, but rarely when I'm there. The venting includes about 5' of 3 inch pipe and 2 90's on the intake and exhaust and it is terminated with the wall cap included with the boiler. i also added a 3x2 reducer to the exhaust to try to add some restriction after talking to Lochinvar tech support.. This boiler is converted to propane and I did set it up with a combustion analyzer. Currently it is running at: high fire CO 126ppm, CO2 8.9%, O2 5.1%, low fire (minimum) CO 5ppm, CO2 9.6%, O2 3.8%. The last time I was out there, I increased the gas pressure a little bit to get the numbers listed above, and it worked great for 3 days, then it howled all day long on the fourth day. This seems to happen at low fire, and once it starts, it will not stop until the boiler shuts off. I need to get this fixed as the customer is starting to loose patience, and I don't blame him. I would appreciate any ideas. Thanks.

PaulR

Questions

Questions for you:

What size boiler is it and what pump is on it? 

Is there a wye strainer? 

What is the system pressure?

Has the system been cleaned and is there any system treatment or glycol in it?

Paul

Nick S

KBN080

Sorry, the model is a KBN080 with the Grundfos pump that came with it set on speed 2. There is a wye strainer and I cleaned the system with some Hydrosolve, but currently it is full of water. The system pressure is at around 12 pounds. The noise seems to be coming from the inducer harmonics, and the customer describes it a s a fog horn, which I guess I would agree with. I have heard this noise on some of the Munchkins I put in in the past, but it always went away with the throttle screw adjustment (with an analyzer of course). Aside from the noise, the boiler works perfectly. Thanks for the reply.

clammy

differental adjustment

had this promblem on a munchkin ended up calling tech servie and had to adjust the differental on the gas valve ,the unit has been fine since give there tech servie a call to ensure it's still with in it's specs peace and good luck clammy

Derheatmeister

fog horn

I used to have that same problem with some of my TT installs...

The fix was to bring the O2 on low fire up which will also lower you CO2..

Is this a Honeywell gas valve? if so you may want to Adjust your Offset screw just a little bit as well to get your values from high to low fire tighter. Good luck.

eluv8

howling knight

While it could be the differential, on a Lochinar be very careful touching that differential unless its in writing from the factory! They used to and may still have it covered with a sticker. I would try what Derheatmeister has suggested first your numbers do look within specs, however they are a little off from where I have been for silent operation and a short vent run. I usually only had the problems when converting to LP with short vent runs. Took a little work to get the darn things dialed in. Lochinvar has also had problems in the past with the mounting of the heat exchangers requiring a stiffening plate to silence some howling noises as well. Rare but I have heard of others needing the modification to resolve their noise problems.Good luck.

Mark Eatherton

2 things to look for.....

1st, look on the bottom of the PVC air intake pipe within the boiler vestibule. There is SUPPOSED to be a 1/4" hole drilled in the bottom of the pipe. If it is not there, it will randomly howl.



The other thing I have seen is that the fuel input needs to be boosted in order to avoid flashback into the burner assembly on low burn. In other words, richen the fuel mix some on low fire. If we had access to the minimum burn RPM;s we could avoid this issue, but it would raise the minimum output of the appliances.



I don't know if anyone else has done this, but when I was setting my Munchy up on LP this past weekend, it started fog horning, and I had my combustion analyzer in the vent, and it maxed it out and shut it down on CO.



DO NOT ALLOW THIS CONDITION TO CONTINUE... Correct it as soon as possible.



Sometimes a person has to do what a person has to do in order to keep things running cleanly, even if it means having to operate the appliance at a higher CO on low burn then what the factory would like to see.



Technically, as long as you are operating at less than 400 PPM CO, the appliance is consider "safe"... and within accepted industry (GAMA?) standards.



Making the burn as clean as possible is an ideal consideration, but when the burn is occurring INSIDE of the burner, the amounts of CO produced are far more dangerous and detrimental than running slightly above recommended PPM's.



Just relaying my field experiences. Anyone else seeing this?



PS, this is NOT a problem that is tied to the Knight product alone. It is a problem tied to any sealed combustion, negative pressure gas valved system, and that includes a WHOLE bunch of different manufacturers.



The ONLY boiler I have NOT seen this happen on is the Vitodens. I suspect it has more to do with burner design (Matrix burner vs stainless steel chain mail wrapped perforated pipe) than anything...



ME

eluv8

High Co

Mark, I have seen extremely high CO levels when the gas pressure coming into the boiler sees a pressure drop over about an inch of water column from static. Even if the gas pressures are above 4" W.C. if the pressure drops from say 7" W.C. to 5"W.C. the neg reg gas valve will not regulate properly from what I have seen in the field. Simply changing the gas flex to the boiler or correcting pressure drop to within 1" W.C. can make huge differences in combustion numbers.

Nick S

Offset adjustment

Thanks for the replies. I think this is a Honeywell valve, but it definitely has an offset adjustment with a sticker saying the warranty will be void if you touch it. I have made this adjustment on other boilers before, but I guess Lochinvar doesn't trust us. Oh well, the howling seemed to get better with more gas anyway, so I'm not sure if raising O2 will do it or not.  Mark thanks for the tip on the intake hole. I will check it next week when I go back there.

eluv8

Lochinvar differential

Ya, the sticker sometimes comes off but they have been doing it since almost the beginning of the knights history. Evidently something about their valves, they "tech support" told me about 3 years ago that they didnt even have the equipment to adjust the differential. If raising the gas pressure helped, that lends me to believe that you might have a pressure drop issue. Have you checked static vs full fire and low fire gas pressures? I havnt used a Lochinvar for some time but I dont think they have changed much.

technicalsupport

We would like to help

Sir:

            If you would please provide the model and serial number of this heater I will be happy to check our records to see where we can help you from here.  There are multiple ways to correct such an issue in a timely manner.  Is this a high altitude unit?  How long are the vent and air intake runs?  Please feel free to contact Lochinvar Technical Support at 1-800-722-2101.  It sounds like you are still having trouble and we would like the opportunity to help you solve this issue.  If we work as a team I am sure we can get to the bottom of this.

Nick S

tech support

I will call on Monday. See the first post for vent lengths, they are within the minimum listed in the instructions.

Techman

noisy knight

At the last KNIGHT night class a stiffiner bracket was discussed that  stopped  a noise complaint that occured at low fire operation ,and without the bracket the noise stopped once a higher fire operation was resumed.

Nick S

Bracket

I received the bracket from "technical support", but no explanation of where it goes. "technical support" says it goes from front to back on top of the heat exchanger, but the cabinet is 12" deep, and the bracket is around 14"? The bracket seems to be for a bigger boiler, but "technical support" claims that is the only one they make, and they think I'm an idiot.  Has anyone installed one of these brackets that can shed some light on where it goes? Thanks.

technicalsupport

Bracket

Sir:

This would appear to be a misunderstanding.  The bracket actually goes on from side to side, or left to right.  These brackets are one size fits all.  If you have any further questions please do not hesitate to call us on our service hot-line 1-800-722-2101.

Mark Eatherton

Trust me...

they DON'T think you're an idiot. Lochinvar doesn't roll that way.



Looks like a simple misunderstanding, and we ALL have those.



ME

Magnehelic

It Happens

On all boilers that have the Honeywell Neg Reg and the French Design HX.  (it is a potential on all of them.....happens on very few).  Once the gas valve is adjusted per tech support's instructions (which they won't instruct you on til they have ALL info.........due to the danger of CO and the fact that the boiler WILL soot up if left running in this state), it quiets right down.  It's a pain, but like I said, we have dozens of Knights out there on both gas and propane, and it has only happened on one propane fired unit.  We have a lot but less Munchy's and it was more prevalent on them.

Nick S

Update on knightmare

Technical Support, I guess there was a misunderstanding as I am now told the bracket does not fit on the KBN080, only the 105 and up.



I am at my wits end with this thing. Just when I think I have it fixed, a week or two later it starts howling again, and now it goes off on flame failure and locks out. I did add some elbows to the venting per tech support, but it did not solve the problem. The offset adjustment was off on the gas valve, so tech support had me replace it. I guess the offset adjustment is off limits? I have adjusted the combustion numbers all over the range with the same result. I had the guy from the supply house out to look at it with me since there is nothing else I can do with it and he has no more ideas and wants to replace it. That was three weeks ago. I haven't heard a thing. Today the homeowner called and it is now howling everyday, and locks out at least once a week.



So, I think I will replace the boiler with something else on my dime. Preferably a mod/con with a non French (the name escapes me right now) heat exchanger. Most brands are available to me, but I do not have any experience with anything other than the Munchkin and Knight. I would appreciate any suggestions.

CMadatMe

One Last Ditch Effort

Have you considered getting the boiler mfg there and not just the supply house guy. I don't mean a rep agency either but a factory rep. If this problem was my trusty Vitodens I know the Viessmann guys would be right there with me. I'm sure somone from this boiler mfg would. I'm not familiar with the Knight but can you limit modulation either low or high? Get the boiler out of low fire until you can get someone out there.

Nick S

factory

Supposedly the wait has been on the factory or the factory rep. I'm not sure which one. The guy from the supply house went on vacation until the 22nd, so I have no way to contact the factory rep. Wonderful. I'll check on the modulation limit, I'm heading there tomorrow. Thanks.



Speaking of the Vitodens, how is the 100w?

CMadatMe

Vitodens 100

Sweet, simple and priced right. Have put out about 50 since they came available in August and haven't had one problem what so ever. The 200 is in another world with what you can do with it.

eluv8

howling knight

Hopefully tech support has given you a personal visit. and got you operating. I personally am not a fan of Lochinvar products due to the problems/reliability I had with their products. I currently am using Peerless Purefires with good sucess similar design nice control, and a lesser known company Hamilton Engineering Evo for higher priced jobs and commercial projects. Triangle Tube also has a nice boiler that has had great reports if you are looking to get away from the Giannoni design. Really it depends on the support you can get in your area.



Some of these things you may have already checked but it does not hurt to repeat. It sounds to me like you are still having problems with combustion and or draft. Especially if you are now having ignition problems. Do you know for sure the analyzer is reading correctly, if the analyzer has not been calibrated in over a year chances are its off? How does the flame look off the burner at low fire and high fire? I think you are stilll running lean or perhaps getting flue gas recirculation compounding a  problem. What are your static and full fire gas pressures before the boiler gas valve, you should not have more than 1" drop preferably less? Are there any other gas appliances that could be affecting this boiler? Has the burner and gasket  been inspected for leaks and proper assembly, sometimes the burner gasket does not get seated correctly? Is the heat exchanger slightly tilted to the back and level side to side? What are your draft readings on the combustion air inlet and on your flue outlet during low and high fire? Do your O2 readings on the combustion air inlet match your O2 reading outside? Are you getting any debris or material in your condensate lines?



Sorry for the long post, but I know what its like to have a problem you cant solve. If you have done the things mentioned above and are still having an issue then Lochinvar needs to make it right.



Good luck and thanks for keeping us posted. Hopefully through your experience and willingess to share another will not have to go through the same struggle to correct a problem.

Mark Eatherton

Last ditch efforts...

I think I'd be contacting the local manufacturers rep for some in field assistance.



Also, one thing we forgot to talk about is the required separation in distance between the primary regulator and the regulator on the appliance. If there is not enough distance, the two reg's will "see" each other, and will set up a resonance between the two diaphragms and that will cause problems.



Everyone who makes widgets occasionally gets a lemon. This might just be yours. Take the lemon, and make lemonade out of it and you will have a customer for life.



ME

Nick S

Regulator

I think the I&O manual says 6 to 10 feet as a minimum between regulators. Wouldn't that just mean 6 feet? I don't know, but from the propane regulator outside I have about 8 feet of 1 inch and 3 feet of 1/2 inch black pipe and a couple of 90's. I have checked the inlet gas pressure with all appliances running and with nothing running, and it does not vary much at all. It stays around 11.5", even when it howls. I am willing to add some length to the gas line if you think it may be my issue. What are the usual symptoms of this? Thanks, you guys are coming up with ideas I haven't thought of.

Nick S

Doesn't matter now

I was at the house today to see if there was anything I could do and I could not get the thing to howl or fail to light. The customer did say it was howling all morning. So, I cleaned the heat exchanger out, and there were a few "coffee grounds" in there, but nothing out of the ordinary for a propane fired mod/con, although I did clean it out once this winter already.



Unfortunately, it looks like the only way to keep the customer happy now, is to replace the boiler with something else. The customer goes out of town a lot and is very worried he is going to come home to a frozen house and the howling has to be pretty annoying too. I guess I can't blame him. I really can't afford to do this, but I REALLY can't afford not to. All of my work is through referrals, and this customer is friends with my in laws. Talk about a bad situation.



I will say, I still like the Knight boilers, and I don't blame Lochinvar for these problems. The tech support guys did try their best to help, but in this case the customer has lost faith in the product, so we have to move on. Thanks for the help guys.

Mark Eatherton

Final suggestion.

Our good friend Paul Rohr now works for Lochinvar. Give him a call and tell him of your dilemma and see if he can help you out. LP is a strange beast in and of itself.



I have a Lochy in the field (KBN500) that howls, but only at one particular RPM. Sounds like a civil alert siren when it does. It sits in a remote mechanical room, so I've never gotten a complaint on it. Could be you have the same situation.



Any way, call Paul and see if he can help you out somehow.



ME

Steve Whitbeck

venting

I had a similar problem with a Munchkin M140 that the installer had used 4 inch PVC instead of 3 inch.

I ended up installing a 4 to 2 reducing coupling on the exhaust pipe with a 12 inch of 2 inch pvc pipe ,coupling and SS screen.

Then retest the CO levels.

The problem went away.

I tried a 4 to 3 reducer that didn't help.

Your vent pipe is TOO big - You need to reduce it further than back down to 3 inch. Go to 2 or maybe even 1 1/2 inch.

Try it you would be surprised.

Is your flame blue or is it orange.

Blue is running lean. with the nit burner the flame should be orange.

eluv8

howling knight

You should not be getting so much "coffee grounds" put a level on the header of the heat exchanger and make sure it is leaning back 1/4" or you will cause excessive wear to the target wall. "the coffee grounds" and will cause accumulation on the flame sensors and ignitor leading to flame failures.



Before tearing out check your inlet and outlet flue pressures i am guessing you have next to none if not a negative draft at times on the flue. Lochinvar on propane can be a pain to tame. You might give Lochinvar another call and find out what your pressures can be and try what Tinkerer has done. It may take 2" on the outlet and inlet or 1-1/2" like he says. Just be sure and check your CO and combustion after Reducing the flue and combustion air.



The one I had that did this was on propane as well and was a KBN105. My fix for the boiler was restricted venting and running low fire as rich as I could within manufacture recommendations. I dont remember what the allowable stack pressures are or if Lochinvar could even tell me. That was too long ago.

Nick S

Vent size

I agree the venting is too big for this boiler, and I wondered why you can't vent it in 2 inch when some of the other mod/con french heat exchanger boilers are. I did add 4- 3 inch 90s to the intake and 4 to the exhaust. Now it looks like something from a Three Stooges episode and it still didn't help. The vent is terminated with the wall plate that comes with the boiler, so I can add a reducer to the exhaust, but not the intake. Maybe I should just redo the venting with 2 inch? Then the boiler won't be installed by the book though. The only time this boiler runs at 100% is when it has been reset from a lockout, and it is trying to catch up, so I doubt it would be an issue. Now that I think about it, the only time the boiler did not seem to howl, was when it was running pretty rich, but it got pretty nasty in the heat exchanger with "coffee grounds" in no time. Are you saying this could be caused by the pitch of the heat exchanger? I'll see if I can get back there tomorrow to check it. There seems to be no pattern or reason this boiler howls. It happens in all weather, and it will be fine for a few days, then howl for a week straight. It makes no sense. Thanks again for the help guys. I'll keep ya posted.

eluv8

coffee grounds

If the coffee grounds are a kind of pasty mush its very possible you have high levels of humidity in the combustion chamber which is usually caused by poor drainage or a heat exchanger not pitched towards the drain. This is not going to be related to the howling noise which is an entirely different problem from what I understand.



What is the local Lochinvar rep telling you?

Nick S

Rep

Ahh, pitch for the drain. I was over thinking things a little. I thought it had something to do with propane being heavier than air so the burner needed to be pitched to compensate, LOL.



The only people I have talked to about this problem are the tech support people at Lochinvar (many times) and the wholesaler who is dealing with the rep. Today I think I will have to figure out who the rep is and give him a call myself. 

eluv8

any resolution

Any resolutions, 



Thinking a little out of the box, is there glycol in the system or is it straight water? There was some problems with LP fired small tube boilers and glycol making a whining noise that could be resolved by adding an additive.

Nick S

Not yet

I am supposed to meet the factory rep there tomorrow. The system is full of straight water. The boiler ran fine all last week, except one day it howled and locked out all day. I'll keep you posted. 

qtown

howling knight

I am curious as to the outcome of the problem. Was the factory rep any help?

Nick S

No solutions yet

Unfortunately, the boiler would not make a sound when the factory rep came out, so we have no new ideas. I have been in contact with Paul Rohrs and I believe he has been in contact with the rep, so I know we have the best working on the case. The bad part is, we are nearing the end of the heating season, so the time to come up with a solution is limited. The homeowner has agreed to wait until winter is over before we do anything drastic.