Has anyone checked the gas pressure or the burner alignment ? is the flame hitting the bottom of the boiler or is it between the sections .Sounds like it is out of alignment.

A boiler can make steam, at any temperature depemdent on the pressure where the flash may be occuring. This is not your problem though. When this is seen on a hot water system it is usually at the inlet of an oversized and improperly piped pump, the symptom is that the pump will go through a lot of seals.

[Edited by fat eddy on 02-25-2005 at 06:18 AM]

 

I would say the boiler is retaining heat keeping the baffles
hot and when cold air hits them, its giving you the popping noise.

If you keep short cycling that boiler the way you are now,you can look forward to frequent part replacment,as well
as high gas bills.

People make claims that a boiler with mass should not have
a need for a buffer tank,but what happen to a boiler that
is way oversize and on top of that you have very small loads
that not only short cycle the boilers,but put stress on a circulator as well.

Sir, your boiler is crying out for a buffer tank.

[Edited by simpleman on 02-25-2005 at 07:20 AM]

 

4 minute burn cycles is way too short. I agree, a buffer tank should be looked at. If your HW heater is nearing it's life end, why not get a reverse indirect like a turbomax or Ergomax? THese tanks hold between 25 and 30 gals of boiler water with a copper coil for the domestic water to flow through. Kind of like taking a tankless coil from a boiler and sticking it in a thermos bottle where the BTU's won't fly up the flue. You have plenty of extra BTU's to make hot water for the house and now you have a BTU "batery" that the boiler will charge up and the zones and hot water coil will suck the heat out. The boiler should run for at least 10 to 15 minutes and then stay off longer until it needs to fire again.

 

Fat eddy: I will ask the installer to check gas pressure and burner alignment. Could this also cause the BANG on cool-down? The BANG that occurs 60sec after the burners ignite sounds very similar to the BANG that I hear 60secs after burners shut-off. If the burner is out of alignment, then something is getting hot that shouldn’t? Or, something is getting hottER than it should?

Simpleman: isn’t the boiler supposed to retain heat? One of the BANGs occurs only 60 sec after the burner shuts-off. I agree with you about the short cycles: high fuel bills and early mortality.

So, the buffer tank is a place to “dump” some heated water, the object being to pull the unused heat out of the boiler?

Johnsp: so an indirect-fired domestic hot water heater could act as the buffer tank? But, it has to be the “reverse” style that you describe. It sounds like it’s not really a zone, but the zones will draw from it. So, it’s in series with the supply?

But, a forward style, would just be another zone, and unless someone is taking a shower, it’s not really an additional load on the boiler. Right?

How would the cost of an indirect-fired hot water with installation plus continued high fuel bills compare with “right sizing” the boiler?

Just as a sanity check: the BANGs seemed to be related to burner activity. How does the buffer tank help the BANG 60secs after ignition? Maybe Fat eddy is closer to the target with his alignment question?

 

That would be something worth checking if the burner is misaligned or overfired it can be impinging on the boiler instead of radiating through the flue section, I think it could make some hot spots and cause noise on startup and cool down.

 

Checkout this design

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,78589,00.html

Your boiler heats up rapidly and get's hit with a large delta T return water.

Yes, check that burner. But an over fired/over sized boiler? I've seen oil burners overfired and blast out the refractory, but gas?

 

Water in a closed loop system will not steam at or anywhere near 190*. You gotta be a lot higher than 212*. At 12 psi your looking at around 240*.

I have seen more than one boiler flash steam with 180 deg & 12 psi.Think about this.If you have a poor water flow situation or air pockets & one tiny spot on the heat exchanger is cherry red.....Would it flash steam?Yes!!!

 

what area do you live in with this problem

 

I under stand flash points on a HX. Making steam and flashing steam arent the same imho. If this posts boiler was makin steam, The original post would have read a whole lot different.

 

I live near Philadelphia.

 

I had the same problem with a boiler our company installed in 2001. We originally install exactly same size as what came out, without checking exactly how much BTU's the actual radiation elements need. After a couple of years of complaints by homeowner, we initially fixed all the expansion of pipes against wood framing. I then realized that the noise is internal. I can actually feel the noise, which is called "Kettling" through the jacket of they boiler.THis boiler has four circulator zones.If yhe boiler is oversized you will have the problem with lack of flow through boiler. When this happens the boiler will short cycle, but it will also cause the water inside the boiler to boil. Because there isn't enough flow through the boiler water isn't being circulated fully through all parts of boiler, causing water that's not moving to overheat and cause the"Kettling" noise. 2 things can be done. First is the boiler can be changed to match what radiation actually installed in the house. Secondly, since the zones are not piped properly for the needed flow of and oversized boiler flow. Installing a bigger circulator won't solve problem if the piping can't provide enough flow. A bypass will need to be installed with a circulator and some type of flow control.circulator needs to run whenever boiler fires. Adjust flow control to achieve proper temp rise you boiler requires. A uncirculated bypass won't work.

Let me know if this helps

 

I had the same problem with a boiler our company installed in 2001. We originally install exactly same size as what came out, without checking exactly how much BTU's the actual radiation elements need. After a couple of years of complaints by homeowner, we initially fixed all the expansion of pipes against wood framing. I then realized that the noise is internal. I can actually feel the noise, which is called "Kettling" through the jacket of they boiler.THis boiler has four circulator zones.If yhe boiler is oversized you will have the problem with lack of flow through boiler. When this happens the boiler will short cycle, but it will also cause the water inside the boiler to boil. Because there isn't enough flow through the boiler water isn't being circulated fully through all parts of boiler, causing water that's not moving to overheat and cause the"Kettling" noise. 2 things can be done. First is the boiler can be changed to match what radiation actually installed in the house. Secondly, since the zones are not piped properly for the needed flow of and oversized boiler flow. Installing a bigger circulator won't solve problem if the piping can't provide enough flow. A bypass will need to be installed with a circulator and some type of flow control.circulator needs to run whenever boiler fires. Adjust flow control to achieve proper temp rise you boiler requires. A uncirculated bypass won't work.

Let me know if this helps

 

LinkMech

I agree but he has already posted that a loop was installed and the it is circulating. His boiler is large for his home but it still should not be making expansion and contraction noise, which is what I beleive it is and not flashing or steaming.

 

I'm with you, Eddy.

Noel

 

I think he said a bypass was installed but he did not say a circulator was installed on the bypass loop.

 

Again, thank you everyone for your comments.

jrc2905, there is only 1 circulator, TACO 007-F5, 1/25hp, 3250rpm, pushing into the boiler. Flow thru the boiler should be a constant, right? Circ is already running when boiler fires. Boiler will not fire unless circ is running. When t-stat(s) are satisfied, everything shuts down. (see previous comments for start-up sequence). By the way, how many gpm does this circ move?

Installed radiation:
Zone1, 70’ of bb (x600BTUH max radiated capacity = 43000), 205’ of pipe excluding bb, serving 850sqft to be heated
Zone2, 60’ bb (36000 max radiated), 100’ pipe, 650sqft
Zone3, 70’ bb (43000 max radiated), 50’ pipe, 500sqft
Zone4, 30’ bb (18000 max radiated), 130’ pipe, 300sqft
House Totals: 230’bb (138000 max radiated), 485’ pipe, 2300sqft, approx 25 gal in pipe & radiators plus 6 gal in boiler.

About the bypass, other contractors and the rep have looked at the by-pass and said that it's been installed properly: 1" vs the 1.5" return; There's a ball valve on the bypass. The bypass enters the return before the circulator, but after another ball valve. The ball valve on the return is used to restrict flow on the larger return pipe to ensure that the circulator is pulling on the by-pass. (If I close the valve on the return to 50%, the boiler reaches hi-temp limit in about 90secs!)

 

The ball valve before the circ should be left wide open, do not use it for flow control, it can cause cavitation.
Zone 1 is too much for a 007, you have almost 18' of head.

 

Been there is correct,there not enough pump at all for all
that piping.You did say one circ?

 

Mark115 , Whats the GPM required across HX?? THat 007 is way to small, the pump that comes to mind for your system would be a Grundfos 26-64 or 011. Id also really consider primary secondary piping, this way youll never starve the boiler . You need to find GPM across HX reqiurements.

 

I think a 0014 would work for you.

 

"HX"?
do you mean the expansion tank?

 

If it is the pump , why does it make noise ?

Why would an undersized pump give you a expanding and contracting noise, if you turned the pump off and the flow protection, the boiler would cycle on limit but it still shouldn't make noise. JMHO

Now if it is getting severely slugged with cold water it may be a problem, but not likely with water that is in the envelope of the home,if you have some pipes running through an attic or some other unconditioned space I suppose it would be worth investigating.

[Edited by fat eddy on 02-27-2005 at 02:31 PM]

 

"HX"?
do you mean the expansion tank?

He means the boiler its self.

The water vessel is the heat exchanger.

 

When is your contractor coming back? and be sure to post results of fix

 

F.E. Quit pickin apart everybodys post were trying to help the guy. He says it happens at the beginning and end of the heating cycle, a possibility exists that gpm across HX is not being met causing thrmal expansion. If this isnt the case , a boiler of this quality could use some protection. His system could benefit from Primary secondary near boiler piping wouldnt you agree?? I mean a 007 for this size system, I realize its not a high mass radiant system but proper flow across HX is a must!