Are Furnace Gas Valves Interchangeable – Step by Step Guide

  • By: Rakib Hasan
  • Date: January 10, 2022
  • Reading Time: 4 min.

The world is made up of a constant amount of energy. According to the law of energy conservation, energy in this world can neither be created nor destroyed but transformed continuously from one form to another, hence, the amount of energy always stays constant. The transformation or conversion of energy is crucial, otherwise, the world would not have reached this stage ever.

However, as important as this characteristic is, the transformation of energy can be equally dangerous. Take the Second World War for instance. The tragic event of America dropping two nuclear bombs on Japan and decimating two cities in the process is very well known to all. During the explosion, massive amounts of energy were converted to thermal energy, resulting in the deaths caused by lethal heat, and wind energy to the point of creating a destructive shockwave that destroyed everything in a 2-mile radius. This is what happens when you fail to control energy transformation. 

A popular way of controlling the use of energy and hence, the energy conversion is the use of valves. A house furnace, like any other appliance, also applies the valves for this reason. But many ask the question—are furnace gas valves interchangeable?

Furnace gas valve and its role

A furnace gas valve is used to control the amount of gas used in a furnace for producing the desired heat. It does this by controlling the opening of the gas passage, similar to a door of a house. 

The gas passage is connected to the meter which can sense the amount of gas flowing to the unit. If the valve is on, it means that the gas passage opening is completely open, causing the pilot light of the furnace to light up. The gas flow can be then controlled using the valve with the meter providing information about the gas flow amount per unit time.

If the valve is turned off, which means the gas passage is completely shut down by the valve. This will cause the pilot light to go off. This combination of the valve system and pilot light is common in most heating appliances. But gas furnaces are simple devices and if their gas valve somehow does not work or goes out, it should need a replacement. To replace it, you need to interchange it with a new one. Can it be done though?

Furnace gas valve and its role

Different types of furnace gas valves 

Gas furnace valves can be of different types. Let us get introduced to some of them before we know if they are truly interchangeable.

1) Gas chain- This is a manual valve. The user needs to turn the valve on and off by hand using the valve handle.

2) Solenoid valve- This is an automatic valve. The valve is connected to a thermostat which controls the valve according to the user’s needs.

3) Pilot safety- This is a valve that stays open only when the thermopile that has employed a thermostat reaches a particular temperature because of the flame of the pilot light. 

4) Combination gas valve- A version from the 1960s, this valve can work as a valve knob, a regulator, a thermocouple, electric terminals, and even a solenoid valve. Due to technological advancement, these valves are no longer used.

When are furnace valves interchanged?

The good news for you is that furnace valves are very much interchangeable. All you need to know now is how to figure out the right time for interchanging because you would never want to change a healthy valve system. If the valve system is not working, follow these few steps before going for the replacement procedure. 

  1. Have a look at the pilot light to check if it is on or off. 
  1. If the pilot light is off, check out the furnace’s manual to see how to relight the pilot light. 
  1. Relight the pilot light by following the manual’s instructions. The pilot light should be lit up after that but the main valve may take a few moments to open up.
  1. The meter also shows the correct voltage occurring in the thermopile. Check it because enough voltage is required to keep the safety valve open. Otherwise, you should consider replacing the thermopile.
  1. Check if all the safety devices in the circuit have enough voltage. If the devices are not working, that should indicate the interchanging or replacement of gas valves.
Cost for interchanging furnace gas valves

Cost for interchanging furnace gas valves

The cost for interchanging depends on several factors such as the number of wires on the valve (if there are more than two, the cost will increase), the type of valve you want to interchange, location of your house, climate in your area, and the HVAC company you will choose to help you out.

The price range can be 6,000tk to over 34,000tk with an average price of 30,000tk to over 50,000tk.

Quite expensive, isn’t it? Very troublesome too. The reassuring news is furnace gas valves do not usually go out so you do not have to interchange them very often, maybe after 6 or 7 years after you bought the furnace only if you are unfortunate. The valves are employed to keep you and your gas bills safe, so they are manufactured very soundly. 

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