Hello,

In my previous house there was a feature of the thermostat / AC system that turned the blower on for something like 15 minutes per hour.

Our new house has a Lennox Heat pump and a Lennox CBA27UHE Air Handler. What I have found is that this house is so well insulated that we get stagnant temperature and air. So I would like to install something that turns the blower on for about 15 minutes each hour. It doesn't have to be at the same time each hour.

Does anyone know about an addon that would add this feature.

If not, would someone help me understand if there are some thermostat wires that I could use a relay to connect that would turn on the blower? I believe I can construct a timer and relay combination to add this feature if a off the shelf item is not available.

Thank you in advance for your help and guidance!

Ray

 

Welcome to the forums.

The green(G) wire would get connected to the red(R) wire to get the "blower only" to run. Basically the same thing as "fan on" at the thermostat. That is the easiest way to do it but the blower will be running at the same speed as if the unit was in A/C mode. That could be annoying.

There may be a possibility of accessing a lower speed tap. Is that something you'd want ?

 

If the existing thermostat is nothing special, you could replace it with one that has the periodic blower activation feature … or you could connect such a thermostat in parallel with the existing thermostat with only the power (R,C) and blower (G) wires connected

 

A Honeywell TH8321R1001 thermostat has this function and will support a heat pump with Aux heat.

 

Hello,

Thank you for the wiring help. Same fan speed is fine.
I looked at the replacement thermostat and thought the cost was too much.Will have to see.

Thank You again,

Ray

 

There are many timer choices you could use if you decide to go that way. The one in the link runs on 24vac and repeats the programming. There are many different voltages to choose from. If you got one that ran on 24vAC it could be installed at and run by the system directly. This one plugs into a sub base. You could just pull it out to stop the process.

Ebay timer (as example)

 

Hi Pete,

This timer looks like it is in the right price. One thing is not clear to me is I see one delay time setting. Since I want the fan to run for say 15 minutes every hour how do you do this with only one setting? I am sure the answer is staring me in the face but I am missing it.

Thanks for your help!

Ray

 

That may not be the best choice here. I'm checking at Omron. They have a line of basic timers.

Omron timers

ebay/Time-Delay-Mult-i-function-al-Timer-H3CR-A-D-PDT-11-Pins-With-Socket

 

You might check the thermostat to see what the temperature differential from off to on is and try a smaller difference. For example if the current difference is 2 degrees F, try 1.5 or 1 so that the system will cycle more frequently .