# Time delay relay



## PlumbBob^2Pants (Oct 10, 2009)

I'm a carpenter and usually spend most of my time over in the carpentry forum, but I'm over in this part of the forum today hoping to get some insight as to why the blower motor on my heat pump is acting up.

The blower motor cycles on and off, again and again, several times in succession when the AC is on and then it finally snaps out of it and either continues to cool or turns off when the room temperature is at the level set on the thermostat. Sometimes it will do this cycling event when it first starts up, or when it should be shutting off when room temp setting is achieved. The old motor's bearings were shot and it caused the whole air handler housing, floor, and wall to shake. So I replaced the motor, hoping that was the cause of the problem. THe problem still persisted, but the vibration and shaking are gone. Next, I replaced the old analog Trane Weathertron thermostat with a Honeywell RTH7600D, hoping it would have been an old, worn out, faulty analog thermostat causing the issue, but the problem still persists with the Honeywell t-stat. I next traced the green wire all the way back to the air handler to make sure there wasn't a loose connection, and there wasn't. 

How probable is it that the time delay relay is faulty, causing this cycling of the blower motor? If this is most likely the cause, where can I find a replacement time delay board for it? The blower motor is a model TWV030B140A1 ... here is a picture of the relay ...


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## beenthere (Mar 5, 2009)

I replace a couple of them a year for this very same problem.

I get them from Trane.


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## hdung91 (Feb 13, 2013)

My experiences, you should take your system model number to find out the part online.Some part might be replaced or can be use by another. Mostly, all Hvac electrical component can universally switched. They are depending on the current one you have. Let say you have a Timer relay 4 port 24v come out 2 port 120v for Blower. Then, you can properly find another matching to replace it.
Hope I wont answer wrong question


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## PlumbBob^2Pants (Oct 10, 2009)

beenthere said:


> I replace a couple of them a year for this very same problem.
> 
> I get them from Trane.





hdung91 said:


> My experiences, you should take your system model number to find out the part online.Some part might be replaced or can be use by another. Mostly, all Hvac electrical component can universally switched. They are depending on the current one you have. Let say you have a Timer relay 4 port 24v come out 2 port 120v for Blower. Then, you can properly find another matching to replace it.
> Hope I wont answer wrong question


Thanks, guys. I found the compatible time delay relay online by searching for it with the system model number ... should be easy to install.


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## hdung91 (Feb 13, 2013)

You are welcome. I know that the first time for fixing the hac system, the hardest part is to understand the right part. I got confused for the first time buying the component. After some research, I found out that the devices or those components are doing the same job even different model. Thats all. Except the Coil system, they have different refrigerent in it.


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