Aprilaire 5000 operation light

[rsg]

I had an Aprilaire 5000 installed over a year ago. I have had the contractor who installed it back twice.
First the light stayed on all of the time (after blower shut off). They came back and it worked for several months.
Next the light would not come on at all. They replaced the door. It worked for several months.
Now the light is staying on all of the time again.
I would not mind paying to get this resolved but have lost confidence in this contractor. Any suggestions?
Thanks

[MoveOver]

I had an Aprilaire 5000 installed over a year ago. I have had the contractor who installed it back twice.
First the light stayed on all of the time (after blower shut off). They came back and it worked for several months.
Next the light would not come on at all. They replaced the door. It worked for several months.
Now the light is staying on all of the time again.
I would not mind paying to get this resolved but have lost confidence in this contractor. Any suggestions?
Thanks

How is it powered, a regular 110V outlet or a switchted outlet that is only powered when the fan comes on. Maybe it is plugged into the wrong outlet.

It should be powered by a outlet controlled by the furnace.

[mark beiser]

How is it powered, a regular 110V outlet or a switchted outlet that is only powered when the fan comes on. Maybe it is plugged into the wrong outlet.

It should be powered by a outlet controlled by the furnace.

Excellent point!

Where does the air cleaner plug in?
I have never sold/installed and Aprilaire 5000, but every single one of them I have seen was just plugged into a regular electrical outlet, which is is WRONG.

The installation instructions are rather specific about how it is to be wired. It must only receive power when the blower is running. If it is plugged into an outlet that always has power, the light will always be on.

If they have it wired one of the correct ways, the possible cause of your problem can vary.
If they are using a current sensing relay, or sail switch, to switch power to the air cleaner, the relay or sail switch may have stuck closed, so the air cleaner is getting power all the time.
If they are using the EAC terminals that some furnaces have, it could be that the furnace control board is incorrectly powering the air cleaner all the time.

Without seeing how it is wired, we can't really tell, but if it is just plugged into an outlet that has power all the time, they need to send someone out, that can read simple installation instructions, to correct it.

[bobb25]

The fact that it worked correctly for several months, leads me to believe that it's wired correctly. I'd start looking at the unit itself.

[rsg]

It is powered by a outlet controlled by the furnace. The outlet was wired as part of the installation.

[mark beiser]

It is powered by a outlet controlled by the furnace. The outlet was wired as part of the installation.

Then if the light is on all the time, it isn't a problem with the air cleaner, something has gone wrong with whatever is switching the power to the outlet the air cleaner plugs into.

[bobb25]

It is powered by a outlet controlled by the furnace. The outlet was wired as part of the installation.

Might be a good idea to double check how it's wired. If it's a duplex receptacle, the tab between the two receptacles can be broken off. One receptacle can be wired to the furnace, and the other hot wired. This is commonly done when there is no other receptacle close, and the installer wants a place to plug his drop light into while the furnace switch is off.

[rsg]

Thanks everyone for your input.

The outlet is a duplex with one dead and the other for the unit. It is wired using a sensor (I believe a Model 51 but not Aprilaire brand).

On one of the previous service calls they did replace the sensor and the unit started working properly. The contractor stated that these sensors rarely go bad.

[MoveOver]

The fact that it worked correctly for several months, leads me to believe that it's wired correctly. I'd start looking at the unit itself.

The light can only be on if the unit gets power. These units just have a power cord, no controls. So the outlet must be powered when the fan is off.

[mark beiser]

Thanks everyone for your input.

The outlet is a duplex with one dead and the other for the unit. It is wired using a sensor (I believe a Model 51 but not Aprilaire brand).

On one of the previous service calls they did replace the sensor and the unit started working properly. The contractor stated that these sensors rarely go bad.

Model 51 is the number for Aprilaire's 115v current sensing relay, and is the one they specify in the instructions for the air cleaner.

I don't think I have ever found one bad, that was being used in the correct application.

As long as it is rated for 115v, and 50w(.42A), it should be the correct relay.

With your system set up the way it is, that relay is the only thing that would be causing your problem...

[quid_non]

Hi All!
I also had an Aprilaire 5000 unit installed on my late model (~5yr old) Carrier heat pump. It went dead after ~2-3 yrs of use (naturally out of warranty...). I went to replae it and discover that they changed the activation design from an internal airflow detector (old design) to a current sensing relay activation. Here is the issue... The Model 51 current sensing relay has a MINIMUM activation current of 4A. The high eff blower on my carrier unit draws, at best (hi speed) less than 0.5A.

So... When I bought the new Aprilaire unit, installed the relay, it would not power up. It works fine if plugged directly into a 120V AC outlet, but will not switch off when the fan shuts off. Unfortunately, the circuit board in my Carrier air handler box does not have any "EAC" (electronic air cleaner) take offs. It does have 2 24V take offs, one I use for an Aprilaire whole house humidifer.

Any suggestions to get the Aprilaire 5000 unit wired for correct shut off? Can I get a new current sensing relay rated for less than 0.5A instead? If so where? Any possibility of using the additional 24V takeoff on the board with a different relay?

Thanks for the time and suggestions!
Best
quid_non

[webbheat]

Wrap the motor wire three times around metal strap on 51 relay and your problems will be taken care of.

[mark beiser]

Hi All!
I also had an Aprilaire 5000 unit installed on my late model (~5yr old) Carrier heat pump. It went dead after ~2-3 yrs of use (naturally out of warranty...). I went to replae it and discover that they changed the activation design from an internal airflow detector (old design) to a current sensing relay activation. Here is the issue... The Model 51 current sensing relay has a MINIMUM activation current of 4A. The high eff blower on my carrier unit draws, at best (hi speed) less than 0.5A.

So... When I bought the new Aprilaire unit, installed the relay, it would not power up. It works fine if plugged directly into a 120V AC outlet, but will not switch off when the fan shuts off. Unfortunately, the circuit board in my Carrier air handler box does not have any "EAC" (electronic air cleaner) take offs. It does have 2 24V take offs, one I use for an Aprilaire whole house humidifer.

Any suggestions to get the Aprilaire 5000 unit wired for correct shut off? Can I get a new current sensing relay rated for less than 0.5A instead? If so where? Any possibility of using the additional 24V takeoff on the board with a different relay?

Thanks for the time and suggestions!
Best
quid_non

The furnace control board should have an accessory terminal to supply 115v when the blower is running.