Furnace 不工作, 急! 请教高人
- 主题发起人 hitony
- 开始时间
Fan will not run if blower door is not closed of switch defective.
When you say 火苗, is it the pilot ? Or the furance does fire but goes out after a short peroid of time?
If it goes out after a peroid, it would be the bi-metallic switch in the burner area. You can try to clean the contacts.
Typically, the furance burner will shut off after fire under three different states:
1/ Normal shut off - controlled by the thermostat when the preset room temperature is acheived.
2/ It will shut off shortly after fire if the burner switch dosen't sense high enough temperature or switch is open (defective).
3/ It will also shut off shortly after fire if blower is defective such as no enough air flow or the blower not even working, that the limit siwtch (over temperature) is on due to high temperature.
Your Furance uses a limit switch (The one that connected with black/red/yellow in your picture) for the safety control which will shut the burner off if the air flow is not enough.
Here's a link to the functional description of a fan limit switch.
Furnace Fan Limit Switch Control: a guide to the fan limit switch, settings, manual fan override, temperature settings for warm air heating furnaces - Honeywell L4064B Combination Fan and Limit Switch
By the way, there are many different types of control method. The new ones uses pressure swtiches as well. but your is a low cost old style. It should not be that difficult to find out the problem.
There's a shop called Boone in ottawa, they carry spare parts.
When you say 火苗, is it the pilot ? Or the furance does fire but goes out after a short peroid of time?
If it goes out after a peroid, it would be the bi-metallic switch in the burner area. You can try to clean the contacts.
Typically, the furance burner will shut off after fire under three different states:
1/ Normal shut off - controlled by the thermostat when the preset room temperature is acheived.
2/ It will shut off shortly after fire if the burner switch dosen't sense high enough temperature or switch is open (defective).
3/ It will also shut off shortly after fire if blower is defective such as no enough air flow or the blower not even working, that the limit siwtch (over temperature) is on due to high temperature.
Your Furance uses a limit switch (The one that connected with black/red/yellow in your picture) for the safety control which will shut the burner off if the air flow is not enough.
Here's a link to the functional description of a fan limit switch.
Furnace Fan Limit Switch Control: a guide to the fan limit switch, settings, manual fan override, temperature settings for warm air heating furnaces - Honeywell L4064B Combination Fan and Limit Switch
By the way, there are many different types of control method. The new ones uses pressure swtiches as well. but your is a low cost old style. It should not be that difficult to find out the problem.
There's a shop called Boone in ottawa, they carry spare parts.
谢谢楼上的答复! 
上个月我请人清洗了furnace, 然后开Furnace后忘记开送风电机约一小时, 后打开送风电机,furnace正常工作了2天, 然后就不工作了.
Furnace的后挡盖子原来是盖好的,为了拍照才打开. 火苗一直都有,另附上多图, 望有用.
电压测量: RH--W. 26V, RH--Y 26V, RH--G 26V 全是交流电压.RH=RC.
电路图里那个继电气体阀门控制器 都有26v的交流电.
电阻: 室内温度小于设定温度时. RH---W 之间导通, 反之 不通. Y--RH 电阻一直变.
请问, 那个FAN/LIMIT CONTROL 是如何工作的? 我认为温度调节器正常, 不知对否?
上个月我请人清洗了furnace, 然后开Furnace后忘记开送风电机约一小时, 后打开送风电机,furnace正常工作了2天, 然后就不工作了.
Furnace的后挡盖子原来是盖好的,为了拍照才打开. 火苗一直都有,另附上多图, 望有用.
电压测量: RH--W. 26V, RH--Y 26V, RH--G 26V 全是交流电压.RH=RC.
电路图里那个继电气体阀门控制器 都有26v的交流电.
电阻: 室内温度小于设定温度时. RH---W 之间导通, 反之 不通. Y--RH 电阻一直变.
请问, 那个FAN/LIMIT CONTROL 是如何工作的? 我认为温度调节器正常, 不知对否?
附件
谢谢楼上的答复!
上个月我请人清洗了furnace, 然后开Furnace后忘记开送风电机约一小时, 后打开送风电机,furnace正常工作了2天, 然后就不工作了.
Furnace的后挡盖子原来是盖好的,为了拍照才打开. 火苗一直都有,另附上多图, 望有用.
电压测量: RH--W. 26V, RH--Y 26V, RH--G 26V 全是交流电压.RH=RC.
电路图里那个继电气体阀门控制器 都有26v的交流电.
电阻: 室内温度小于设定温度时. RH---W 之间导通, 反之 不通. Y--RH 电阻一直变.
请问, 那个FAN/LIMIT CONTROL 是如何工作的? 我认为温度调节器正常, 不知对否?
It's highly likely the limit switch problem.
The fan limit switch is a safety control which protects the furnace heat exchanger from damage (such as heat exchanger cracking due to overheating) by turning the burner off on the furnace gas or oil burner if the temperature inside the warm air supply plenum (just above or just next to the heat exchanger) gets too high.
Also,
W is the control back to the furance.
Y is the control back to the A/C compressor.
G is the Fan control
RH should be hot side of the 24Vac,
RC should be the common side of the 24Vac.
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不懂什么叫“火苗一直都有”。正常情况是火苗起来后（代表gas已经供给了），有个定时装置在一定时间后（１，２，３，秒后）风扇启动，送出热风。这个定时的长短是可以调节的，应当要修理工来调。如果火苗起来后，过了一定时间，风扇还不启动，煤气（gas）就自动关闭（没有风扇送风会把零件，铁板风道给烧化了）。所以不应该有“火苗一直都有”的现象。你的情况很像module坏了。我的那个是去年换的（１５年）。你若能找到module，记下型号，也许能到你的furnace dealer处买到。不过装起来不容易。
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It looks it has power supply as there is the pilot flames and the vent fun runs.
谢谢楼上的答复!
上个月我请人清洗了furnace, 然后开Furnace后忘记开送风电机约一小时, 后打开送风电机,furnace正常工作了2天, 然后就不工作了.
Furnace的后挡盖子原来是盖好的,为了拍照才打开. 火苗一直都有,另附上多图, 望有用.
电压测量: RH--W. 26V, RH--Y 26V, RH--G 26V 全是交流电压.RH=RC.
电路图里那个继电气体阀门控制器 都有26v的交流电.
电阻: 室内温度小于设定温度时. RH---W 之间导通, 反之 不通. Y--RH 电阻一直变.
请问, 那个FAN/LIMIT CONTROL 是如何工作的? 我认为温度调节器正常, 不知对否?
Your measurement is good, the thermostat just working fine.
Y--RH is for air conditioner during summer.
W--RH is the control for the furance. It's just working fine.
For your reference, see below wiring description.
Very high possibliity is the limit switch, don't need to be worry to take the unit out and inspect it. check the contacts if they're burnt or not. If it's burnt or dirty, clean it as much as you can, scrape it with a knife/file etc to keep it running for few more days.
Take a picture of the unit and go to Boone (check their address in internet) and buy a new one. Their price is the best.
W is the control back to the furance.
Y is the control back to the A/C compressor.
G is the Fan control
RH should be hot side of the 24Vac,
RC should be the common side of the 24Vac.
