New life for the old Mueller

Timco

This poor old beast had two DHW exp tanks turned upside down for expansion. The press flew from 5-25# when she fired up. It was straight gravity.(great excuse to buy my first 36" Rigid wrench! She's a beauty!!) I forced the water with the circ shown and re-piped a proper exp tank. This one was oversized, as the correct one was a week out. Piped the water/exp tank on the return manifold, across the boiler from the circ, still pumping away. Cust would not consider a new boiler....old 4-plex. Cries broke. The press now goes from 15-19#, and the water is set back to 160* from 180. It heats up totally evenly now (before it was 2 hours before the farthest unit got heat) and twice as fast. Happy customer. Stack temp is only 210*, and lots of draft.(-.05 WC) Tall stack.

Tim

kevin coppinger_4

you are not....

leaving it w/ the stack at 210*F are you? Does it have a new liner?....kpc

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Timco

Original 45' stack, single wall liner. Was looking for suggestions on how to damper the draft to get a better stack temp. Boiler is 1942.

Tim

Steamhead (in transit)

Try a \"neutral pressure point\"

this is covered in Tim McElwain's manuals.

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Maine Ken

At 210* with a -.05 draft you are not going to get the stack temp up to a safe point by lowering the draft. That puppy is short for this world!!!!

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Timco

Could you elaborate? I am west...Tim is east..and they did not cover a neural press point in my classes.

Tim

Timco

Short? -.05 was greatest reading. -.03 was lowest. Windy day.

Tim

Scott04

Tim,

Have you checked your thermometer lately? With one of those old beasts, I would be very suprised to see a stack temp that low. At that temp, it is a constant rainstorm in the chimney and the boiler. That is what Ken meant by "short for this world".
Also, unless I'm missing something, lowering the draft would decrease the stack temp. With a .05 draft, I just don't see a temp of 210* as being possible.

Again, test your instruments! Using testers only help if they are accurate.

Scott

Timco

I'll recheck it against my fluke with a probe. Test was done with my fyrite pro 125...just a year old. Wouldn't less draft increase the temp? LARGE ventacross the back, and gaps all along the floor. There is alot of rust flake in the bottom (on the floor) inside this beast. Blew it all out prior to firing. COAF was 42ppm, excess air was over 350%. I have the printout in the truck.

Thanks,

Tim

Scott04

Tim,

If that unit is leaking that much air into the combustion area, it needs to be tagged unsafe, and made inoperable. In this case it really doesn't matter if a new boiler is "out of the question". The unit is unsafe PERIOD! The HO has NO say in the matter. You worked on it, now YOU own it. If anything happens with that unit, YOU will be held accountable.

With that much air leaking in, that explains the low stack temp. In this case less draft would be better. Normally, less draft lowers stack temp because it pulls the gasses out slower so they are in contact with the heat exchanger longer and transfer more heat into the water. In your case, the high draft is pulling more cold air from the room, thereby reducing stack temp.

Scott

Timco

8" vent..45', 8"connector...3'. 215,000BTU. First readings : 343.6%Ex Air, 210* stack temp, 16.6%O2, 2.4%CO2, 8ppmCO, 39ppmCOAF. New readings : 122.4 Ex Air, 342* Stack temp, 12.1% O2, 5.0% CO2, 9ppm CO, 21ppm COAF.

LESS DRAFT. Was -.06 WC, now -.02 WC....thanks for the advise!

Tim

Dale

stack temp

I may have missed the fuel type, looks like nat gas, or maybe propane. As the other posts suggested the stack temp is way too low, since the flue pipe design seems to be original and this looks like an atmospheric burner you need to raise the vent temp by checking input and since you have probably already done that, checking outlet water temp. I think you will need a bypass line to hold the outlet temp above 140 degrees. This may also be a job where you need to convert to a barometric damper.

Scott04

Tim,

I never gave it a thought that this unit could be atmospheric gas. I do mainly oil, and have seen units very similar to this one. The information I gave is for an oil fired unit! (I assume it also holds true for a power gas unit as well) The reasoning for the draft/flue temp is the same, but, of course, the whole unsafe issue would only apply to the oil or power gas.

Scott