noisey boiler-very loud


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Old 10-17-09, 04:15 AM
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noisey boiler-very loud

hi...just had a plumber install a lochinvar rbn090, about 5 years old its out of a house that a addition was put on and now undersized.
the unit worked fine for 4 days...very quiet. until now..a loud hum that goes thru the whole house is heard.the pump is working fine..also he did install a bypass on the boiler...thanks
 
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Old 10-17-09, 10:07 AM
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Naturally, the first advice would be to get the guy back in who installed it...

Can you 'localize' where the noise is coming from?
 
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Old 10-17-09, 01:37 PM
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the whining huming sounds like its everywhere...very loud.when i turn the zone valves on manual... its seems to go away for a little while,also air shoots out the air seperator when i open it.
 
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Old 10-17-09, 03:29 PM
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Not sure what you mean by "when I open it" ... if that's an automatic air vent, it should be open all the time.

It sounds as though you might have a lot of air in your system. Not sure why that would be making a 'humming' noise though... (unless it didn't know the words... ba da boom).

I suppose the first thing is to make sure that all the air is bled out of the system and you have the correct pressure in it.
 
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Old 10-18-09, 08:13 AM
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im sorry..not open up the air vent valve,which stays open...i meant when i open up the zone valve lever from auto to manual...also i think i have determined the noise is a vibration sent thru the pipes to the whole house...but holding them with my hand at the boiler does nothing to dampen it.
 
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Old 10-18-09, 09:10 AM
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Air comes out the separator when you manually open a zone valve? That's pretty weird...

But obvious that you've still got a lot of air in the system.

Would it be possible to take some pics so we can take a look? Might give us some ideas.

free account / Image hosting, free photo sharing & video sharing at Photobucket / upload pics there / drop a link here for us to view your album.
 
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Old 10-18-09, 09:59 AM
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hi...hope i did this right...here goes thanks

rtricar album
 

Last edited by NJT; 10-18-09 at 10:09 AM. Reason: fixed link
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Old 10-18-09, 10:12 AM
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Is that 'Great Stuff' expanding foam around the flue pipe?

You need to get that crap out of there... it's probably combustible, who knows what poisonous gases it will release when it burns, and even if it doesn't burn, who knows what gases are being driven out of it when it's heated?
 
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Old 10-18-09, 10:24 AM
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What happens when you open that bypass valve just a wee bit more? That valve itself could _possibly_ be the source of the noise, ball valves aren't good for 'throttling' applications, a better valve for that would be a good quality GLOBE VALVE.

I really doubt that you even need a bypass if both of those zones are fin tube baseboard. Close it and see what happens to the noise.
 

Last edited by NJT; 10-18-09 at 10:49 AM.
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Old 10-18-09, 10:33 AM
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That doesn't look like great stuff. The expanded "bead" is quite large. Probably some other product.
 
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Old 10-18-09, 10:44 AM
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First, make sure that the circulator is pumping toward the right in the pics... I know it's an 'obvious', but should be checked... stuff happens.

Your boiler is 90K BTU ? If so, then the 1" (looks like) pipe is probably OK, but your plumber transitioned to 3/4" too soon. The flow through the boiler is being 'choked' by the sections of smaller pipe between where the zones join, and where the pipe transitions to 1". I don't like those "Y" connectors either... they might be OK on the return side if the two returns were feeding into a 1", but on the supply side? I can't imagine that you don't have some pretty terrible 'turbulence' in the piping at that point.

What speed is the pump on? 3 is probably too high... what happens to the noise on different pump speeds? I'm wondering if the pump may be cavitating.
 
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Old 10-18-09, 10:47 AM
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Originally Posted by drooplug View Post
That doesn't look like great stuff. The expanded "bead" is quite large. Probably some other product.
respectfully disagree...

If that stuff was shot down in the gap between the pipes and filled up, it could easily make a bead that large. There's probably an equally large (now burnt up) bead on the INSIDE.
 
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Old 10-18-09, 10:53 AM
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hi...first thing is the foam i put there being the flue sizes were different the other was 6 this is 5...its fire retardant foam the flue pipe went in considerably to the chimney.
the bypass position regardless of where i turn it,eventually will end up making noise.
the boiler is 90,000 btu.
 
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Old 10-18-09, 11:16 AM
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and pump is flowing to the right
 
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Old 10-18-09, 11:21 AM
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i did close the bypass and the noise went away for awhile...but eventually returned !
 
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Old 10-18-09, 11:51 AM
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OK... it took me a while, but I think I finally found the manual for your boiler at Lochinvar website... it seems they don't make those anymore and I had to find where they 'hid' the archived stuff.

It appears that your boiler is of the copper tube heat exchanger variety, and as such is VERY sensitive to having the proper flow through the boiler. Without enough flow through the boiler, the DELTA TEE (difference in temp between supply and return) rises too high, and the boiler can be damaged.

So first things first... CLOSE THE BYPASS to insure as much flow as you can through the boiler! You do NOT want to bypass ANY of the flow around the boiler.

Bottom line is that your boiler is not installed correctly, sorry to have to tell you this.

The BYPASS is on the WRONG SIDE of the the circulator pump. Your plumber installed a BOILER BYPASS, and this is TOTALLY wrong for this type of boiler. Your boiler requires a SYSTEM bypass which puts the bypass on the other side of the circ pump.

Additionally, the pipe sizing issue I previously spoke of comes into play here also... it is further choking down the flow of the boiler.

Very basically, you need to flow around 9-10 GPM through that boiler at ALL TIMES when it is firing. The piping installation must be such that this is guaranteed at all times.

Do you have the manual for the boiler ?
 
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Old 10-18-09, 11:54 AM
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its fire retardant foam
That's a plus, but it's still not the correct application. That foam is for use in structures, to seal up areas of framing in the house that require 'fire blocking'. I seriously doubt if it's rated for continuous use at the temperatures it is seeing at that flue pipe.
 
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Old 10-18-09, 01:08 PM
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Very basically, you need to flow around 9-10 GPM through that boiler at ALL TIMES when it is firing. The piping installation must be such that this is guaranteed at all times.
This was 'off the top of my head', based on the boiler size, the ACTUAL spec from the manual is 7.3 GPM at a 20 temp rise across the boiler.
 
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Old 10-18-09, 01:09 PM
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hi...no i dont have the manual...i do appreciate the time you put in to hepling me though.any sugjestions ? i did close off boiler bypass,and just by looking dont think i have the room without major mod to put bypass on the other side.
 
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Old 10-18-09, 01:25 PM
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Hey Troop, can you post the link to the manual please?

Sorry to say this is going to be a substantive repipe to get it right.

That fireblock foam HAS to be removed. The service temperature of that stuff is only 200F. You need to use a real refractory chimney cement/mortar. You can find it at the local hardware or plumbing supply store. Often comes in a premixed, ready to use plastic bucket.
 
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Old 10-18-09, 01:39 PM
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i will take the foam out asap...thanks
 
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Old 10-18-09, 03:31 PM
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Manual link

take ya right to the PDF:

http://www.lochinvar.com/_linefiles/RB-RW-i&s.pdf

dont think i have the room without major mod
You may have to do that then... in fact, I would recommend that you go with one of the primary/secondary setups that is in the manual, that way you still get full flow through the boiler at all times without sacrificing flow through the system.
 
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Old 10-18-09, 03:57 PM
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I can't see far enough down on the gas piping to tell if there is a 'sediment trap' installed or not... since yer gonna have the plumber there, check to make sure that is right also.
 
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Old 10-18-09, 04:01 PM
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For your exhaust vent (smoke pipe) you need a reducing thimble to reduce the chimney opening to the required size for the boiler. Make sure the smoke pipe does not enter into the chimney flue area.
 
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Old 10-18-09, 04:03 PM
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what if...this is just an idea...leaving the wrong bypass in,just keeping it closed and unused,and putting a bypass...right after the pump before the y,and then bring it foward and drop it down to grab the intake pipe...just a idea.
and ps there is a sediment trap..thanks for asking.
 
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Old 10-18-09, 05:10 PM
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That is a possiblity... if you close the existing valve, there's no real reason to take it out. Close it and take the handle off and throw it away!

BUT, the bypass, and all the piping leading to it, need to be at least 1", so you will have to replace some of the piping.

Next, what you will notice is that now the house is not going to heat evenly, because by adding that bypass, you will be diverting flow from the space heating system... and when you do that, you start asking for uneven heating problems.

This is why I'm recommending going to primary/secondary setup, with a second pump on the heating loops. This way, you insure the flow through the boiler is correct, AND you have the proper flow through the system.
 
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Old 10-18-09, 06:21 PM
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Originally Posted by NJ Trooper View Post
take ya right to the PDF:
Such a nice boy. Thanks.

Figure 48 on page 35 is what this should be. Primary/secondary.
 
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Old 10-24-09, 01:32 PM
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hi again, i think i will go with the primary/secondary that you recomended...so far i havent really used the heat and really dont want the plumber back...i am actually going to attempt this myself...dont laugh...lol. i dont know if you remember the piping diagram but if i just cut the second pump into my system it should basically be piped close to the diagram...the only thing im unsure of is were it has the inlet and outlet and says 12" are they tee's and is that the bypass...or does this pri/sec not require the bypass ? thanks
 
 

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