It’s currently controlling baseboard heating in an apartment. Next, adjust the heat anticipator, which fine-tunes the point at which the thermostat turns off the furnace burners. Line-voltage thermostats have much thicker wires. The thermostat tells the system when to turn on and shuts it off when the house temperature has reached the desired level. I know I need a 24 volt step down transformer but am unclear of where to install it or if a relay or anything else is needed. If the HVAC system fails to turn on at all, there are a number of thermostat problems that should be considered before assuming the furnace or AC unit is to blame. Shorted turns cause the turns ratio from primary to secondary to change and thus an output voltage change. Use appropriate gloves and there is no other more important safety rule than to wear THESE (taps glasses) safety glasses. I’m looking to replace my old Honeywell thermostat with a smart one like Nest or ecobee. If you see 120 Vac or 240 Vac on the thermostat, a low voltage thermostat will NOT work with your system. Basically, whenever the breaker is on, the heaters are on, and vice versa. If a furnace or AC system turns off and on again frequently—a symptom known as short-cycling—it is usually because the electrical connections within the thermostat are not making clean, consistent contact. It is a simple one zone residential oil burner unit. A place where people can come to learn and share their experiences of doing, building and fixing things on their own. Archived. Active 6 years, 4 months ago. For example, on a bitterly cold winter's day your furnace might start and stop quite often. Unless the fault is in the furnace. If a wire is loose from its terminal, place the wire back on the terminal clamp and tighten the screw. Locate the heat anticipator adjustment lever arm (Photo 2). A new line-voltage thermostat will … I’m trying to figure out if it’s wired as low voltage or line voltage. I suspect it’s broken as the heat stays on regardless of what temperature I set it at. The back of a Honeywell low-voltage thermostat, left, and a Cadet line voltage thermostat. Notice in Figure 7 that the line voltage thermostat is less complex than a low-voltage This is the back of the line voltage thermostat shown in Figure 7. Shouldn't I be measuring 24V+/-? The thermostat can be mounted directly on the heater itself, or it can be mounted on the wall so that the circuit wiring passes through the thermostat first on the way to the baseboard heater. You will need a line voltage thermostat. Here is a full guide on how to identify & possibly upgrade if required. As noted in a previous post, I also *removed* the thermostat entirely, and flipped the breaker on, and the heaters immediately warmed up. Double check wiring and check for 24 vac between R and C. E2 will clear 15 sec after proper voltage … First, let’s work to get a handle on what sort of issues exist and what they’re called. This type of voltage is common with electric baseboard heating. Viewed 959 times 0. CT30/CT33 Low-voltage Thermostat 5 Set adjustment lever (CT30 only) 1 Separate cover from thermostat, and remove the plastic insert. It sounds to me as if someone didnt ground the common side of the low voltage circuit. How to calibrate thermostat. Then you go upstairs to the old thermostat and pull the wires up through the wall so you're pulling out the old and bringing up the new at the same time. As long as the furnace is reasonably modern, it should have a panel with screws that the current two are connected to. Take note of the different size of wires between the two types of thermostats. You don't need an electrician to do this work, but you may want to seek advice on which terminals on your furnace are what. Press question mark to learn the rest of the keyboard shortcuts. The best indication it is low volt is the wire gauge. The 2 wire thermostat for line voltage systems are technically known as single pole thermostat (and the 4 wire version is known as double pole thermostat). Test on a known source like 120v outlet, then test your circuit, then test the known source to ensure your meter wasn’t blown testing the circuit. You will notice that it is done when the reading on your multi-meter slows down. Is my thermostat transformer voltage too low? Low Voltage / 24 V Single Programming Electronic Thermostat 1 offer from CDN$ 60.00 Honeywell TH1100DV1000 Nonprogrammable Heat Only Thermostat, White - 1 Pack Finish installation 1 Align the 3 tabs on the cover with slots on the thermostat, then push gently until the cover Set the thermostat to its highest setting, and clean the coil again. If the transformer is functioning properly, check the low-voltage wires to the thermostat. Dimensions of the product are 3.5” x 5.125” x 1.125” and it has a vertical slim profile. These thermostats are called low voltage because they run off a transformer that reduces line voltage from 120 volts to a level somewhere between 12 and 24 volts, depending on the brand of furnace you own. One common failure of the transformer in a furnace that results in a higher than normal voltage, assuming that the input line voltage is at the correct level, is shorts between adjacent turns or layers in the primary winding of the transformer. The factory wiring is a heavy-gauge wire that can handle higher amperage conditions than a low-voltage thermostat. Please use a tester. Hello, I want to convert my line voltage (110) thermostat to a low voltage (24) system. Try moving the lever one calibration mark closer to the "longer" setting. The site may not work properly if you don't, If you do not update your browser, we suggest you visit, Press J to jump to the feed. I actually had this problem on a cooler last week where I had 16V between R and C. I’d like to add two things, one, be wary of advice from internet persons. Yes this is a two wire system. One of … A healthy thermopile in an open circuit test will read between 650 to 850 millivolts or somewhere in between. 2 Use a pencil to move the adjust-ment lever to the proper setting for your system (see table below). Buy an inexpensive multimeter and test, as the color of the wires means jack squat if a goon installed it. Ask Question Asked 6 years, 4 months ago. Adding: You can turn off the heat, probably, by disconnecting one of the wires in the thermostat. You need a tstat that is two wire compatible. In fact, many thermostats are powered by the 24 volts from the transformer. The thermostat is the control device that provides a simple user interface with the internal workings of your homes climate control system. Voltage Drops At Thermostat - Faulty wiring? However, be aware that when outside temperatures are radically higher or lower than the desired indoor temperature, it is normal for the HVAC system to cycle fairly frequently. The reason we do this is so we give the hot side a reference point to ground. Disconnect both ends of the wires from the transformer and check for continuity after turning the thermostat all the way to its highest temperature setting. Line-voltage thermostats have much thicker wires. I see techs in the field get the most frustrated when they have a low-voltage short they can’t seem to locate. The low-voltage transformer mounted somewhere, often near the electrical panel or near the heating or cooling equipment supplies normal power to the thermostat; if one of those wires is disconnected, the transformer burned up, or power to the equipment where the transformer is mounted is turned off, the thermostat will go blank You would disconnect the two old wires from the furnace and twist/tape a new set of four-line low voltage solid copper to the old ones. However, from the look of this, I'm betting that your current thermostat is nothing more than a continuity switch, no different from a light switch. Sometimes the furnace or AC system will run but fail to set the temperature you've selected. Virtually all central heating and air conditioning systems are controlled by a low-voltage thermostat that tells the system when to turn on and shuts it off when the house temperature has reached the desired level. The smart ones usually need a "common" wire or something like that. The connecting pipe at the bottom of the boiler should not bend too much. Set the thermostat to its lowest setting, and clean the bimetallic coil with a soft brush or compressed air. "E2" on temperature display Brownout condition or too low of voltage to thermostat. It’s not compatible with line voltage systems, 3 wire hydronic systems, heat pumps and cooling systems. Looks like you're using new Reddit on an old browser. hi I have a Honeywell t6373a1108 thermostat on a high voltage circuit with five wires connected to it, I would to know how I can convert it to low voltage so i can put a Nest thermostat, I will attach an image of the thermostat with the wiring exposed, help would me much appreciated Hold down the gas control’s thermostat knob until the maximum voltage is reached, which may take three minutes or so. not about to make holes to run 3 new wires. 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