Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
My oil burner runs for about 90 minutes, at which point, it starts cycling on and off. I'll hear it humming for about 60 seconds - and then it will shut for about 30 seconds. It keeps repeating. On/Off/On/Off...
Any ideas if this is a problem? Is it normal? I have a boiler guy coming next week who I am sure will hit me up for all kinds of things. I just want to make sure this isn't dangerous or a sign of a serious (expensive) problem.
Do you have your domestic hot water being heated by your boiler?
Quote:
Originally Posted by purelygeneric
My oil burner runs for about 90 minutes, at which point, it starts cycling on and off. I'll hear it humming for about 60 seconds - and then it will shut for about 30 seconds. It keeps repeating. On/Off/On/Off...
Any ideas if this is a problem? Is it normal? I have a boiler guy coming next week who I am sure will hit me up for all kinds of things. I just want to make sure this isn't dangerous or a sign of a serious (expensive) problem.
It's a hot water boiler; one-zone; manual Honeywell thermostat. Since I'm new at this, I'm not sure how it SHOULD sound!
It appears to go on and off once it approaches the 'target' temperature. Also the temperature gauge does not appear to be working well. It either goes past 30 or stays low - both appear to be inaccurate.
If your boiler is firing for 90 mins. straight then you have a problem. As stated before, the humming sound is probably your circulator & will usually runs another 5 mins after the boiler cycles. As far as the temperature gauge...are you sure your not looking at the pressure gauge on the boiler? Most T'stats dont go below 55 deg.
One more question...when your boiler turns off..are you reading the temperature that your thermostat is set at?
I meant the pressure gauge - not temperature. Let me try to explain this better, as I feel I've done a poor job. - I turn on the boiler; it makes a constant humming sound - The boiler heats for approx. 50 minutes. At this time, it starts to send steam to the radiators. - After a total run time of approx. 90 minutes, the boiler sounds as if it shuts off. This lasts about 2 minutes. Then it sounds as if the boiler restarts. This 'on/off' cycle continues endlessly until I either shut the system or the 'goal' temperature of 72 degrees is met. I hope that helps. Your opinions, thoughts and advice are greatly appreciated!
There is a gizmo that makes a big click before the burner fires. Basically it is a big relay and it is required to close before the burner can fire. A sensor that measures boiler temperature causes this to close or in some set ups it can also close if the thermostat calls for heat. Usually is installed it a box back on the flue outlet. You should hear a distinct click.
So it probably has not failed completely. On the first cycle it closes properly but once it heats up, then does not generate enough force to close again. You will hear all sorts of clicking and things cycling. It might close in for a bit, then drop out. It a sort of common problem, especially in older oil fired equipment. My best guess at this point. Can be a few other things. There is a thermocouple that senses heat after the burner should have lit. If it doesn't, controls assume no ignition and it shuts off the fuel. Waits a bit and tries again, if house is still calling for heat. Could be that also. Your posts are unclear as to exactly what happens, does the burner actually fire during the cycling? If the problem is the main contractor usually it does not. If the problem is the thermocouple it will try. It is unclear how far you get in the firing cycle. Could even be the ignition transformer, anything that prevents ignition but most of those either work or don't they are not typically intermittent.
Typical service call figure at least $100. Thermocouple is ~$5 item, contractor maybe $10 - 15 but you pay an hourly service charge on top.
None of it is particularly dangerous. The systems are designed for flame safety, if everything does not go according to plan, it just shuts down, tries again. The danger comes in if any type of jury rigging occurs without a proper repair.
If you got an old system, best to replace it. With today's fuel prices, you get the money back fairly quick.
You can check the main contractor by just removing the cover, holding in the critter with the butt of a plastic screwdriver. There is power on the contacts so you do need to be careful.
The contractor is a electro-magnetic device and it moves in - out. If you manually push in the circuit is made. Holding it in, if everything runs normal after that, the contractor is defective. Probably how the dude will check it.
The other potential critter is whatever is used to see flame / sense heat. Usually it is a thermocouple. They can get covered with soot or whatever and work sort of intermittent. Some designs might have used an IR sensor but somehow, they have to sense flame is present after the ignition cycle.
Most other things will either fail or work, they tend not to be intermittent in nature.
All the above assumes you have a foggy clue what you are doing.
What Cosmic said, but....
It also could be the limit switches/control.
At any rate, you should have it looked at by a professional, because there just might be something else going on.
A home inspector in AZ is in the hospital clinging to life from a heater exploding in his almost new home. The house burned to the ground, some of his pets died, his elderly Father was able to get out of the house. He has 2nd and 3rd degree burns over most of his body. It's not good.
Have it looked at.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Could be the main contractor
