How does vent safety switch work

With a medium-bristled brush, sweep away the dirt and dust from the bottom of the burner chamber. Use a clean , damp cloth to clean all sides of the chamber, and brush and wipe down the burners. Save my name, email, and website in this browser for the next time I comment.

Press ESC to close. How does a blocked vent safety switch work? Wikipedikia Editors 9 Min Read. Turn off the power to the furnace at the circuit breaker. The circuit breaker is clearly marked. Lift up the blower compartment cover to access the blower wheel and blower motor. Look for a small red or yellow button on the side of the blower motor. Press the reset button down if it has popped up. Table of Contents. Set your meter to volts AC, turn your furnace on so it is calling for heat.

There should be either two or three wires going into your pressure switch. Probe one lead of the pressure with one lead of your meter while touching the other lead of your meter to ground. The furnace lights but then shuts down after a few seconds short cycles The porcelain on the flame sensor is cracked.

The flame sensor is sooty or corroded. If there is a serviceman switch, turn it off. If not, shut the power off at the breaker panel.

Open the access panel and locate the high limit switch. Using a multimeter, test for continuity between the leads on the switch. A cracked heat exchanger is one of the most basic and common symptoms, and also often the most drastic sign of a damaged heat exchanger. Sometimes a cracked heat exchanger has cracks that are simply too small and thin to be directly observed. Odd Furnace Flame Behavior. Show Comments. Leave a Reply Cancel reply.

Share Article:. My concern is oF is above water boiling point- will it ever reach it in case of chimney blockage? Steve You don't give the brand and model flue gas spill switch: some of these devices are deliberately designed to require a manual re-set, for life safety issues are involved. The remedy is to 1. Act on the diagnosis: if an expert monitoring the system at start-up, operating at full temperature, and at shut down finds on flue gas spillage then she'll probably recommend replacing the switch.

Watch out: you don't want to force the switch on as that could cause a fatal carbon monoxide spillage in the building. Anon: The Dunkirk Boiler, as well as most heating equipment, will sport no special manufacturer, model, brand-specific "on-off" switch. Rather the on-off switch will be a standard electrical on-off switch mounted in two or more locations: at the boiler or even on it, and a second safety off-switch mounted outside of the boiler room typically near its entrance. When i sell one i suggest that they do.

Had my CO2 levels checked in my gas boiler. My flue CO2 level was 2, ppm, and zero ppm ambient. I have checked for carbon monoxide and there doesn't seem to be any according to meter. I smell an unusual smell especially during heating season and very cold weather. We have some symptoms of possible gases and also have heard of alderhydes that don't seem to have a smell, they are just there and can make you sick.

Do I call a chimney expert or a furnace man. Furnace seems to be working well, but will furnace guy help us with flue and draft problems.

What do I ask for? Changes such as in wind velocity, outdoor temperature, snow cover, doors or windows open or shut, fans on or off, can significantly change the way gas burning appliances are operated unless careful provisions were made for adequate combustion air and proper flue gas venting.

Links on this page also direct the reader to carbon dioxide gas information in a separate document. Once you are convinced that no emergency exists, I recommend asking for help by a senior gas heat service technician.

The flue gas sensor on our has fired steam boiler keeps tripping off every few days. We installed a new 6-inch chimney liner and a new GSK-3 degree flue gas spill sensor at the draft hood as well as a new thermocouple at the gas burner.

The pilot light on this steam boiler is always on. The building occupant wants to keep the heat set rather high, at nearly 80 degrees F because of current cold weather here in the Northeastern U. Will this high temperature setting and long boiler-on cycles make the steam boiler overheat or cause flue gas spillage? Could the flue gas spillage still be caused by the chimney? Watch out : No user control setting should be tripping off a flue gas spill sensor. In fact longer boiler-on cycles should improve the draft at the chimney as the flue becomes heated.

The problem could be in the heater or in the flue or in site conditions that are causing a downdraft. I'd have the chimney inspected by a certified chimney sweep. Check that the flue size and height are properly matched to the steam boilers input BTUh rating as well as checking that the chimney is not blocked, has a proper cap, is routed properly, has no openings, leaks, nor improper flue sharing etc.

I'd be sure that my heating service company had made a careful inspection of the system's draft, combustion air supply etc. Meanwhile, immediately, be certain that carbon monoxide detectors and smoke detectors are properly installed, located, and working in the building. I have not had hot water since the installation.

The HVAC company is unable to get to my home for some time. They are not from my gas provider. How do the devices work? The little tab is able to be pushed in. It sounds as if that should not occur. Any info is appreciated. I have found your other info very helpful. The flue gas spillage switch you cite includes a manually-resettable feature that is probably the "little tab" that you describe.

When the switch has cooled the button or "tab" is pressed in to re-set the switch. Watch out : because flue gas spillage can kill building occupants due fatal carbon monoxide gas, if a heating appliance has shut down for any reason during normal operation as opposed to during testing the cause of the failure must be investigated and corrected before resetting the safety-switch and turning the heating equipment back on.

The Field Controls GSK3 Gas Spillage Switch is a detector mounted on the draft hood of a gas or oil fired heating appliance such as a boiler or furnace and used to detect flue gas spillage. The switch is wired in series with the burner so that in the event that it detects flue gas spillage it will turn off the burner.

An overheating furnace is usually an indication that the furnace is not venting correctly. Furnaces overheat due to poor air flow through the furnace, improperly sized heating ducts, or if a furnace is too large for the home it heats. If your vent limit switch shuts the furnace down frequently, it may be a warning sign of more serious problems in your HVAC system. Clean the furnace filter regularly as well. Call an HVAC technician to replace the switch if it is not working, and to inspect your furnace to determine and repair the cause of the overheating.

Renee Miller began writing professionally in , contributing to websites and the "Community Press" newspaper.