Wet Pack. How Important To Have One?

Tom_22

When I looked into my big old boiler through the front viewing door I used to see all this powder and cement like stuff on the floor and going up the walls. Finally, last year I vacumed it out with a shop vac. Most of it was reddish. Some of it was white. Some of it was in chunks and stuck to the walls. A little gentle prodding and it all came off. I took out literally fifty to seventy pounds of this stuff.

The boiler is fired at 1.65 gal/minute and I'm going to guess it's about 200,000 BTU or more. That's what my old oil guy said the house required on a replacement. Maybe this one is bigger than 200k.

I'm thinking taking all this powder junk out is going to make my boiler more efficient because it was blocking a lot of heat from getting to the chamber walls. But then I'm wondering, what is this stuff and why is it there? I'm thinking it might have a purpose.

The other day my oil serviceman told me it was a "Wet Pack" that had dried up and turned to powder. He knew it was a reddish color. He said it protected the floor and perhaps the walls (maybe just the back wall) from getting hit directly with flame.

Well this stuff was mostly pulverized and piled up towards the back of the boiler for a couple of years that I know of. Now it's been all gone for most of last winter and up till now.

Do I need to reinstall one of these things? Is there a danger of cracking the boiler from too much direct flame?

Safe and Fun News Years To All,
Jake

Dale

Follow his advice

The original for this boiler may have been fire brick so perhaps that why the wet pack failed too soon. You do need it to keep the head off the sides and bottom of the combustion chamber and to direct the heat up to where the manufacturer wanted the heat exchange to be, you are probably stressing the castings in a bad way and wasteing fuel.

J.C.A._3

Sometimes.....

Rather than using a "wetpack" , there are other options.

As stated previously, the original was probably a firebrick chamber.After they failed, they were usually replaced with a round or square "alumina silica" fire box. This usually didn't fit into the fire area in one piece, and was cut in half, then banded, then backfilled with vermiculite or a comparable fireproof substance, then capped with a wet/mixed material. (lots of these materials contained asbestos, so if you find it be careful).

In the time I've been doing oil service, I've replaced too many to count, and find that a properly sized square "quickie'chamber, seems to work the best. Keeps the flame from hitting the (relatively) cool surfaces of the boiler, which will make for a lousy fire, and the buildup of unburned clumps,which because of their shapes, were lovingly reffered to as "Christmas trees". If you've ever seen them, you'll know why.

If you can fit a "quickie bathtub" type chamber in there(Lynn Products. Model depends on the size of the fire( and your guy wasn't lying about the input.1.65 GPH= about229,000 btu's) go for it . I stopped backfilling them and found that if they get supported from tipping or being pushed back from the head of the burner, they lasted quite a bit longer than anything that had to be cut to fit.

Good luck, and please let us know how you make out. I'd be interested to hear. Chris

Dave_8

Combustion chamber

The other important thing that the combustion chamber lining does is to reflect the heat back into the flames. This is very important to getting the proper efficiency from the combustion process. Get a liner in there and have a reputable firm set the burner to the proper levels of CO2 (or O2). I have seen many a good boiler wrecked running without the proper combustion chamber and many a checking account wrecked by an improperly set burner. Remember that MOST oil suppliers are just that, some of them will throw a new nozzle or filter in for you but they are not doing you any favors, get a GOOD heating firm to set the burner properly and have them check it EVERY fall. NO oil burner can be set by eye, they ALL have to be set with instruments!!!!!!!!!!!!!

Tom_22

Don't quite understand the idea behind insulating the chamber.

> The original for this boiler may have been fire brick so perhaps that why the wet pack failed too soon.

Hi all,

I thought the water in the sections went all the way around the chamber, even on the bottom, so the more of the casting exposed to the heat, it would seem the more of the heat you transfer from the flame to the water to make steam and increase efficiency, not lose it.

Obviously it doesn't work that way from what everyone is saying, but it just seems strange to line the walls of the chamber with an insulator and keep the castings from getting all the heat they can.

I haven't seen a "wet pack", I was just repeating what the oil service guy said. What is a wet pack? A mix of insulating type cement maybe? Did it fill in the spaces between the firebricks?

Tom_22

Setting Flame by eye or instrument

Hi Dave and all,
This flame has only ever been set by eye, with adjustments made to the air blower to get the flame "right." At least it's been that way for the last few years, but probably longer. The boiler is making a lot of soot. Some soot blows out the damper and gets all over everything.

I did discuss getting a CO test with the oil guys and they do them, but it never happened and the service guy said they usually do them in the summer because they're too busy in the winter with no heat calls etc. Perhaps a heating serviceman would be a better idea.

Rocky

Dave is right...

The firebox liner radiates heat back into the flame, which allows the combustion chamber to heat up quickly, allowing better atomization of the fuel, which leads to cleaner combustion. It also protects the metal of the boiler from being hit directly by the flame. This "impingement" is very hard on the metal, and, causes the flame to cool at that particular point, creating incomplete combustion and creating soot. Hire a reputable heating contractor, preferably one who specializes in service work. Make sure they brush and vacuum the boiler flues, reline the firebox, do a draft measurement(to determine how much draft is present in your firebox and chimney breaching) and do a combustion test of your flue gases. Have your heating system serviced once a year. This is akin to getting your oil changed in your car every 3,000 miles: its about the cheapest thing you can do to ensure good operation. Good luck.
Rocky

Alan Muller

chamber needed?

Jake,

Your thinking is quite logical. Oil flames are quite luminous and can transfer a lot of heat directly to the iron of a wet base boiler. Lots of modern boilers are chamberless for that reason. But this is a bit risky in an old boiler--you are in effect re-engineering it--unless you really know what you are doing. I would just clean it out, sit a bathtub chamber in there, adjust the height with bricks if need be, and cut a hole to take the burner tube. It's cheap, and easy, and will last a few years if not over-fired.

am