O.K. it alright to fall over laughing at my question but here it goes…….
My heat exchanger is covered with a 1/4 in of carbon soot. I’ve always thought the heat exchanger is stainless steel because of the high moisture content of a 80% furnance. The furnance is old so if I mess up the furnace I have an excuse to get a new one
I’ve pulled the burner and gas valve. Can I use a preasure washer on the heat exchanger?????????????
I thought I could set up a plastic drain into a bucket and a preasure doesn’t put out volume- 3 gal min.
What do you think
Replies
I'd be more tempted to visqeen off under it and simple green soak and then scrubby with brush and and hand spritz with water for final rinse.
How about if my son hold a wet vac hose at the bottom of the exchanger??
I'm just thinking that's alot of water? But say cover the goodies with a towel or 2 and pre spray to degrease and I guess if it's ok with you. Throw the breaker before and have lots a dry stuff to soak it up.
Good idea with degreaser, only real question- do I want to take a chance on a slow painful death by the wife if a make a mess in the house?
The over temp breaker tripped. Had a friend come over and said the heat exchanger wasn't venting properly with the carbon build up. Got most of the carbon out. Just thought getting it real clean would make it more efficent
Edited 2/16/2008 12:23 pm ET by curley
I know that I'm going to sound like someone over at H-talk, but you need to get a pro to look at it NOW. Soot is a sign of a serious problem. Serious enough that you could end up talking to St. Peter sooner than you planned on.
I agree with rich1--find out what is causing the carbon build up in the first place. Maybe it's just the results of years of service, but why risk your life (and your loving wife's life).
A couple of thoughts on your furnace.
What brought you to investigate the heat exchanger?
Possible causes, Improper ventilation causing back drafting.
Above sea level and never properly jetted.
Gas pressure never set or changed.
Get a carbon monoxide monitor for your house and remedy what ever caused the problem.(call in a hvac pro)
Curley,
I would say that you should get a proffesional involved. This is extremely dangerous territory. But if you decide to forge ahead I hope the following info is useful.
1 You say you have a gas furnace. This refers to a hot air system so I'll base the following on that assumption. Many people use this term to describe any type of central heating system. If you have a hot water boiler there are other things you can do or may need to check.
2 Unless the soot is real crusty and hard the standard of the industry is a "horsehair brush". You should be able to remove any soot in the heat exchanger with that. If I have to do an annual cleaning thats what I have used for the past 20 years. It works great except in very extreme situations.
3 DO NOT USE A HOME SHOP VAC UNLESS YOU HAVE A FILTER SPECIFICALLY DESIGNED BFOR EXTREMELY FINE PARTICULATES!!!!!!!!!!! I've seen many occasions when someone has started to clean their own system and proceeded to vac the soot from the unit and then turned around to find a cloud of soot the vaccum didn't filter engulfing the house
4 Were the burners or grating on the covers full of dust or animal hair? Lack of combustion air is a common cause of what you describe. This is too lengthy a subject to get into but in short you need enough fresh air supply to the furnace to support the btu rating.
5 Is the flue clear?
6 When you get it back together ideally you should check co levels in the flue gas to see if the levels are acceptable and also the discharge air in the plenum to check for a possible crack in the heat exchanger you may not have noticed
7When firing the unit, after the flame is established but before the indoor blower comes on look at the flame. There are many sites where you can get an idea of what a good flame should look like. Here's a critical test though: Again get a good idea of what the flame looks like and how it's shaped with the burner on and blower off. Then look at the flame when the blower comes on. Assuming you don't have a return in the basement(I've seen many of them) and you're getting enough combustion air the flame should not change. If it does chances are excellent your heat exchanger is cracked.
8 The gas pressure in most older units (natural gas, not propane) needs to be 7 to 9 inches of water column supplied to the gas valve and 3 1/2" wc. at a test port in the manifold going to the burners. You can buy a cheap manometer to check this. Most units come with 1/8" tappings in the gas valve and the manifold to check this.
9 I'm assuming you don't have a fan assisted type of furnace. If you do make sure the combustionfan is running
Hope this helps. I may have given you more info than youneed/want but Better safe than sorry