请教：FURNACE不能自动启动怎么办？
- 主题发起人 Anna34
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这是不是说furnace得不到足够的空气燃烧而过载保护，所以启动不起来？
从温度控制器上看，“HEAT”一直在闪，FURNACE却没动静，这时如果手动关上电源再开开电源，FURNACE才会启动。以你看是哪一步不工作呢？
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Does the following sound similar to yours?
Lennox G20 problems - http://www.hvacmechanic.com/ Forums
Our furnace decided to not turn on in the mornings a couple weeks ago when the temps dropped into the 20s. I figured it was the thermostat, so I went out and got a nifty Ritetemp one with the remotes, etc. etc. All was good until today. We have had pretty warm conditions for the past couple weeks, but today the temp dropped back into the 20s, not the teens, and the furnace isn't working again. The first time round, the house was cold in the morning, and I would have to turn the heat off, then back on at the thermostat, and all was good again. Now it's doing it every time. Our heat hasn't kicked in automatically all day. Every time I have had to turn the heat off, then back on at the stat. Once we get it going it goes through the cycle with no problems, but when it cools off in the house again it won't kick back on.
It doesn't seem to be trying to kick on.
Equipment:
Lennox G20 Furnace Model #G20Q3/4 E-100-5
Manufactured 5/8/97
Ignition module is Johnson Control G776RGD-11
The reason I mention the ignition module is because I have heard several stories about these being junk. I have read that there is a Honeywell replacement that lennox is telling people to use. However it's sunday night, and no one to ask. I have not been able to track down a model number for a honeywell replacement for my exact module.
Any input would be greatly appretiated.
________________________________
Lennox used a Johnson Controls "Ignition Control" module on their furnaces, G26 and some others. This is likely the source of your problem. The LED on the module will be flashing one second on and 5 seconds off.
The module fails to supply enough voltage to open the pilot control valve which is part of the gas valve. To verify this problem connect an AC volt meter to the PV connection on the gas valve and ground. Turn off the 115 VAC supply to the furnace and then turn it back on. This resets the control. The normal start up cycle will start with the LED on steady. Observe the burner box and look for the spark to ignite the pilot. You can hear this too. When it is present observe the volage on the meter. It is supposed to be 24 vac. If less significantly you have confirmed a problem with the Ignition Control.
These are repairable if you have skills. Otherwise buy a new one. My observations have let me to conclude that the traces and solder connections on the printed circuit board are deficient. You probably will observe a discolored area on the board. Resolder this area and add copper wire to the circuit boards trace that goes to the PV connection.
The module (ignition control) looks like this:
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I experienced the same problem about a year ago.
The problem was that the pilot flame would be on, then the sensor 没有探测到温度，就会关闭燃气阀门。But (this is typical) it didn't do this following thing: 空转废气马达一段时间后，再重新开始。如果第二次还不成功，不会再试第三次。 Only that 只会废气马达空, and never stopped。
It was the crap module that didn't work. And the replacement part cost around $250 + tax + labour.
It is not 得不到足够的空气燃烧. air for burning is from different source. The air from filter go through the heat exchanger then gets warmed up then sent to your room. Because the heat exchanger is like a hot pot, you don't want dirt in air go on to it. Dirt would burn .So there is a filter. There is a trade off , a "good" filter would filt out of smaller dirt particle but let less air go through. So there is less air to cool down the heat exchanger. There is a sensor on the exchanger if it is too hot , it would shot down the furnace.
You can go back to buy a cheap filter and install it on. If the problem go away then you find the problem.
And there is drain tube let the water out in furnace, check that one too. If it is blocked the furnace would shot down too. Open the front panel you would see it.
Another thing is the furnace has not been cleaned for few years. there is too much dirt on the fan, vaccume the blower fan.
Since your furnace work most of time. I don't believe there is anything broken.
- 注册
- 2003-04-13
- 消息
- 241,073
- 荣誉分数
- 37,883
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- 1,393
