Gas heater lights,runs for a while,then cuts off before reaching set temp. Anyone know what's causing this?

Question

Sometimes it will come on and off just fine. Other times it quits and if we turn it off and then back on it will start again. What's up with that?

Answer 1

If you are refering to a boiler, there are safety shut offs involved. For example, if the pressure in the boiler gets too high, it will shut off. The pressure can get too high, if there isn't enough water in the system. In that case, some of the water turns to steam and trips the pressure cut off. Another reason it might shut off is if their is a water level sensor that detects the fact that there isnt enough water.

Its hard to give you a good answer, because you dont provide enough information in the question.

Answer 2

Sounds like you have either a floor furnace a possible a wall furnace.

It is possible you have what is called a millivolt system. Let me explain.

It used to be that you needed to have 12 volts to through the valve on a furnace. They had transformers hooked to the electrical system to provide that voltage.

Then they designed a valve that didn't take as much power to open it. They were able to used what is called a "generator", which some people call a thermocouple, but they are different. A generator creates a higher voltage to open the gas valve and turn on the furnace.

I had a problem similar to yours in one of my rentals. It turned out to be the wiring. You cannot splice a millivolt system, as it drops too much voltage at the splice. Also, there can be a small amount of oxidation on connections, both at the thermostat and the valve.

This drove me nuts for two weeks. I'd come over and the furnace would work okay, but when I got it to fail, I had to turn the thermostat down then up to get it to come on.

I had a friend that was an HVAC guy, who ended up replacing the thermostat wire between it and the heating unit and that solved the problem.

Good Luck.

Answer 3

this question is 4 years previous yet I purely solved this difficulty by myself 1997 Rheem Criterion II air handler. As various others reported, the project become undesirable ventilation triggering an overheat fault. My first attempt become sliding the analog TS warmth anticipator to at least a million. No success.The purge fan got here on, the igniter lit the gas, even though it flamed out after about 10 seconds. The squirrel cage fan on the bottom got here on and continued to run at the same time as the starting up sequence cycled various cases, observed through device shutdown. I have a Honeywell analog TS, purely replaced. i began tearing down and it is what it grew to change into out to be: THE A/C CONDENSER FINS were CLOGGED! The A/C condenser is stacked on properly of the furnace warmth exchanger. because i'm no longer an A/C guy and didn't wish to dc the freon line, I pulled the gas burner unit and purge fan below the condenser, worked the nice and cozy temperature exchanger out, dc'd the bottom squirrel cage fan and slid it ahead so i ought to lookup from the bottom plenum to work out the A/C fins on the properly of the air handler. The clogged aluminum fins were glaring. This 17-12 months-previous condenser had under no circumstances been wiped clean and had amassed a lot of dust over the fins on the bottom, apparently from clear out/unit leaks. The fix become to gently sparkling the condenser coil aluminum fins from below with a eco-friendly scotchbrite pad (up-down), observed through a thorough vacuuming of the finished unit from condenser to plenum. I wiped clean all sensors at the same time as reassembling in opposite. After reconnecting the ability each little thing worked positive. Unit respiration ok and severe temp limits chuffed!

Answer 4

I'll bet the thermocouple is either bad or not close enough to the flame. That would probably happen to a tank water heater or a wall heater or gas heating stove.

Good luck, and if it gets weird, don't be afraid to ask your local gas company or a pro.

It's always better to pay for a new gas device than to pay for a new house.

Answer 5

first do you have central heat?? if you do, take off the panel on the front of your unit, in front of the burners. there should be one little metal wire on each side, they get carbon on the ends of them and cause the furnace to kick on and off, once the ends are cleaned {with a wire brush or some sand paper} they can make a clear contact and they will work right. your heater should not kick off until your thermostat reaches 1 degree past the set temp.

Answer 6

If it's forced air heat then it could be a dirty filter or a plugged ac coil. Check the filter then check to see how hot the duct work gets if it gets really hot then call to get your furnace air conditioning coil cleaned. If that was irrelevant then it could be a bad ignition module, sensor or circuit board

Answer 7

The safety circuit is protecting you life and your house. When you shut it off your are resetting the circuit. Call a licensed HAVC Tech to check it out.

Answer 8

not enough information