Tip & How-To about Heating & Cooling

How to change a thermostat yourself

Choosing your new thermostat:
Firstly you have to ask yourself why you are changing your thermostat. Is your old thermostat simply broken? Are you wanting a simple upgrade from analog to digital? Are you looking to save on energy costs using a programmable? Are you attempting to integrate your central system into a smart home network? Whatever the reason your choice of thermostat should not be simply the cheapest on the shelf. Different system types may require different thermostat types.
Before purchasing your new thermostat you need to figure out what kind of system you have. The general idea is *H/*C, denoting the number of heating/cooling stages and options, and fuel type (heat pump, gas furnace, electric furnace, etc.). An example would be a typical heat pump- it has a single cooling stage and a dual heating stage (heat strips, compressor) making it a 2H/1C heat pump thermostat. I usually install the Honeywell FocusPro 5000/6000 series for non-programmable/programmable applications for it's ease of use and general reliability.

Before beginning the swap always make sure power is off to both the indoor and outdoor sections!

Determining which wires go where:
First off, you may not ever rely on wire colors to guide you to the proper terminal. We have standard practices for wire color to function, but this varies from region to region and sometimes if a wire shorts out a substitute in the bundle may be used. When removing the old thermostat physically writing down or labeling the wires is not an exercise in tedium- it is almost necessary and something which I do every single time. You will usually have these terminals on the new device:
Rc- Cooling Power (usually jumpered to R/Rh)
R/Rh- Heating Power (usually jumpered to Rc)
Y- Primary Compressor
C- Common
O/B- Reversing valve (activated in cooling/heating)(Heat pump)
W- Primary heat (Furnace or Electric heat)
G- Indoor Blower
E/Aux/W2/X2- Emergency/Secondary heat stage
Y2- Secondary Compressor (2 stage cooling)
L- Communicator for E-Heat (Heat pump)
If you do not have all of the terminals on the old as you have on the new it may not be the end of the world. Required terminals are an R, a Y (if AC is present), a W/W2/E/Aux/X2 (if heat is present), an O/B (if heat pump), and usually a G. Common is optional most of the time as it is used to power the thermostat only and batteries may be substituted. L is not commonly used. If you have any doubts as to which wires go where, stop now. Miswiring can destroy a system's low-voltage and potentially start a fire.

Replacement:
After labeling the old wires and removing the old thermostat, you must attach the new baseplate. Leveling the baseplate is not as important as it was with older mercury thermostats, but still applicable at least within +-5 degrees of rotation. If you are attaching the baseplate to drywall with no backing wood installing wall anchors (usually supplied) is key. Make sure you have a proper length of bare wire (not too long, not too short) before attaching to the terminals. Do not overtorque the screw lugs. Pull back on the wires after attaching them to ensure the connection is proper. It is a good idea to plug the hole through which the wires come with something (I use plumbers putty) to keep a draft from effecting the thermostats temperature. Many thermostats will require some pre-programming before hooking up (refer to installers guide)- I find this much easier to do via batteries before attaching the face to the baseplate. Once the face is on and the power returned to equipment, test the system. Keep in mind modern thermostats include a 3-5 minute delay for compressors as a protective layer.

Common Pitfalls:
Zone system wiring can be confusing and is not as standardized as it should be. If you have a zone system and plan to purchase new thermostats it is highly recommended to call in an experienced service technician.
High SEER and IQ drive systems use very different types of thermostats than conventional systems. For now the newer technology has yet to be perfected in the public market and these changeouts are best left to an experienced professional.
Some older thermostats use B as common (Trane Weathertron for example) This is not to be confused with B as a heating changeover valve and if it is can blow out a fuse,transformer, and/or your brand new thermostat upon startup.
Most face to baseplate interfaces are pin based- if one is not quite careful bending one of these pins during attachment can be irreparable.
Common is the least standard color across installers. Most use either brown or blue, but I've seen some use green and black, usually used for blower and secondary heat respectively. Never assume wire color as a standard.
Most of the service calls regarding thermostats I receive come from homeowners who have purchased and self installed incompatible thermostats. This is something I do everyday for a living, not so for the average homeowner. Take your time and do your research.
Save your manuals- all of them. Many cheap offbrands can be next to impossible to find manuals for online.
When in doubt, call in a pro. Most of us charge around $70-100 to install a thermostat (plus cost). This is almost always much cheaper than a service call to diagnose and repair a low voltage problem.

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1 Answer

how to change thermostat


Instructions
    • Trace the top radiator hose from the radiator to the location where the hose secures to the engine. The metal cover that the hose connects to houses the thermostat.
    • 2Remove the two 10-millimeter bolts that secure the cover onto the engine with a wrench. If you cannot reach the bolts or you are using a socket/ratchet, remove the radiator hose from the metal cover by removing the radiator hose clamp.
    • 3
    • Lift the metal cover off the thermostat to expose the thermostat. With the radiator hose still attached to the cover, lift upward on it to drain the fluid back into the engine. Push the cover and the hose off to the side. If you removed the hose, simply lift up on the metal cover and place it off to the side.
    • 4Pull the broken thermostat out of the engine and place a new one into place. The new one should be orientated in the same manner as the old one to ensure proper fluid circulation.
    • 5Lift the old gasket off the engine and place the new gasket into place. The new gasket should remain dry throughout this process.
    • 6Bolt the metal cover back onto the engine using the old bolts. If the radiator hose was removed during the tear down process, secure the hose back onto the metal cover with the radiator hose clamp.

Aug 29, 2012 | 2002 Dodge Neon

1 Answer

CHANGE TERMOSTATE


Follow the top radiator hose to the motor. Thermostat should be bolted onto the motor at the end of that hose. Simply unbolt and lift out, may need to gently pry with screwdriver. use care to put new one back in just as old one was. also check to be sure that new thermostat and rubber seal are the same as old one. I bought one at napa, and new seal was not the same, had to reuse old one.

Jun 20, 2010 | 1997 Pontiac Grand Am

4 Answers

My 96 aurora keeps overheating and I already changed a leak I had in my heater hose. I believe the leak is coming from the left passenger side probably front or mid front.


It could be a faulty thermostate or a bad water pump. Water pump is on the passneger side where the fan belts are. Good luck

Apr 07, 2009 | 1996 Oldsmobile Aurora

1 Answer

2004 jeep grand cherokee, 4.0, change oil without filter change,


Not sure why the question is even being asked, but you can change the oil yourself in about 15 minutes; simply jack the front end, put a pan under the oil drain plug, open the plug, let it drain, put the plug back in, and add new oil.

Take it to any outlet that changes oil (Wal-Mart, for example, charges about $18, some places charge as little as $15) and they'll include a new filter because otherwise you're running new oil through an old filter, which defeats the idea of the oil change. You can ask them not to put on a new filter, but you'll still pay the base price.

My question is, why would you not want a new filter if you're changing oil.

Let me know if this answers your question.

XMinusOne@gmail.com

Dec 10, 2008 | 2004 Jeep Grand Cherokee

1 Answer

Lines and broken digitized images on the viewing screen


Stevenson


Listen folks, these tv.s do not operate as the old tv. The tv breaks down, you simply change the board you know that has the problem only. You can solve the problem yourself if you want, but you have to know how to diagnose a problem in the new tv. First, you have a power supply board, main digital board, inverter board, and converter board. In your case you need to change the main input digital board. You can e-mail me at Stevebuy31@hotmail.com

Dec 08, 2008 | Akai PDP4225M 42 in. Plasma Television

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