new boiler - new noise

Dale

is moving too fast. Put a throttle valve on the pump discarge and see if the noise abates and the delta T is still 20 or so. Then if that works buy the little taco pump.

Tom_8

new boiler - new noise

I recently replaced an ancient boiler (was coal then oil then gas fired) with a Burnham Series 2 Model 204 (96,000) boiler. I am very excited about the cost savings (about 40%) but discouraged in the amount of noise at the radiators the new boiler makes compared to the old one.

Some details:
Radiators are old American Radiator cast iron.
Used 1.25 inch copper and tied into old cast iron pipes.
Upgraded the circulator on the new boiler to a Grundfos UP26-64.
Put "iso-flanges" on either side of the circulator.
Only piping work that was done was within 10 feet of the boiler. Very simple layout.

I'm wondering where the noise in the system is coming from. Typically should be from air in the system, pump vibration, or maybe restriction in flow. I don't think it's air. The pump itself is very quiet. I'm wondering if the iso-flanges are resticting the flow to the point that they are causing a whine in the system.

I would sure appreciate any input or ideas on how to isolate this noise and maybe get rid of it.

Thanks much for your help.

Tom.

Rich C_2

The 26-64

is a lot of pump for a 96k boiler. You may be hearing velocity noise in the piping network.

You need to calculate the system friction loss and the desired gpm (net btu/10k for 20 deg delta T). This will give you the desired flow/head for your house.

RIch

[Deleted User]

That is a lot

of pump. Rich might not agree. But, why don't you try throttling the discharge iso flange. Might reduce the noise until you can do the math on proper pump.

Hope you piped in a bypass and installed pump on supply.

Good luck.

Unknown

I also think

that the pump is a bit oversized for what you have. Try using the 007 Taco that came with the boiler on and see if things improve. I have been on jobs where this particular pump may have been cavitating a bit and would make the shaft start chattering back and forth with the minute end play in the shaft. Hope this helps.

Glenn Stanton

Burnham Corp.

Tom_8

Thanks - but...

Thanks for all the good advice. I took Ron's advice and tried throttling the discharge iso-flange. It only made the noise in the system louder.

I was wondering if the iso-flange opening was too restrictive next to too large of a circulator. I did install the circulator on the RETURN side (as per advice of the guy that sold me the system).

One last thing: I cannot seem to find a GPM rating for this pump anywhere. Does anyone know how many GPM's this pump pushes versus the smaller Taco pump that comes with the boiler?

(And if you haven't figured it out yet, I'm just a homeowner - not a contractor, installer).

Thanks again.

Tom.

Steamhead

I agree

you're definitely over-pumped.

This sounds like a gravity system that was converted to forced circulation. Assuming the 96K figure is matched to the amount of radiation in the system, you need a flow rate of 15 gallons per minute (GPM). On gravity conversions, it seems to be standard practice to pick circulator capacities at a head (back-pressure) of 3-1/2 feet. Your 26-64 will pump 20 GPM at this head. The Taco 007 will pump 17 GPM at this head, and a Taco 005 will pump 15- exactly what you want. This might not sound like much difference but "less can be more" on a gravity conversion.

I'd lose those iso-flanges. As you've seen, they can be noisy. Using full-port ball valves on the boiler supply and return piping works much more quietly and is easier on the pump.

And always Pump Away from the air separator/expansion tank connection.

To figure radiator sizes if needed, get Dan's "E.D.R." book. For more about Pumping Away, get Dan's "Pumping Away". Both are available on the Books and More page of this site.

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