Question about Aprilaire 600 Humidifier

2 Answers

Aprilaire 600 doesn't seem to be running at all

I replaced the water dispersion mesh assembly on my Aprilaire 600 a few weeks ago while converting my heating system back to it's winter mode and noticed the previous unit showed very little calcification. I made sure the water supply valve is open, the unit is turned on, and the humidity level set on the control unit. After 3 weeks I checked the unit and acn find no evidence water is running through the unit or it is providing any humidity to my system. I don't know what else to check.

Posted by on

2 Answers

Re: Aprilaire 600 doesn't seem to be running at all

If you determine that you don't have a water issue. Remove cover to humidistat and check for 24V AC across the AA terminals. This controls the relay. No 24V, water will not flow.

Posted on Dec 05, 2007

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that gotĀ 5 achievements.


    An expert that hasĀ over 500 points.


    An expert who has answered 200 questions.

  • Expert
  • 298 Answers
Re: Aprilaire 600 doesn't seem to be running at all

Check list
1.check the clamp on the pipe where water line connects
is the hole clogged (water turned off)wont take long
2.Is water flowing all the way to resevoir after turnnig water on
loosen line at reservoir
3.jiggle float water should enter the reservoir inlet to float valevel
somestime cake up,clean float off
4.Remove pump cap clean impeller and standpipe
5.clean reservoir,and close everything up

Usually the hole in the pipe is clogged up in step 1 or the float is sticking if there is no evidence of water in the reservoir

Posted on Nov 21, 2007

Add Your Answer

0 characters

Uploading: 0%


Complete. Click "Add" to insert your video. Add


3 Points

Related Questions:

1 Answer

Black mark on water panel, up or down

Goes up usually. If there is a yellow one it goes up. they usually just mark the top side intended to point upwards. The mesh material has little "u" shaped cups to slow the water from running straight down and out of the drain. Also when you get it going make sure you are not draining more than a liter of water every 5 minutes otherwise you are ready for a new feed tube and orifice to regulate the water flow properly. Good luck!

Dec 19, 2013 | Aprilaire 600 Humidifier

1 Answer

My aprilaire 600 continues to have water running down the drain at all times, whether the furnace is running or not.

Hello, usually when a humidifier continues to run with the furnace off it means that the solenoid valve is stuck open and must be replaced.

Feb 19, 2011 | Aprilaire Humidifiers

1 Answer

Water does not seem to be going through the unit

With the heat on, turn control knob back&fourth from test.U should here a click each time.If no click check hum transformer power.If it clicks flush out water supply pipe poss cloged.

Feb 27, 2010 | Aprilaire 600 Humidifier

1 Answer

Aprilaire 600 humidier: water continuously runs

sounds like you may have it wired to a continuous power source vs one that shuts off with the furnace. The most common wiring is red to C & white to W

Jan 08, 2010 | Aprilaire 600 Humidifier

1 Answer

Aprilaire 600 humidity level too low

The max the aprilaire can put out is 45% Rh. Your humidifier may wired up to run only when the heat is on. In some cases this is not enough time to maintain your humidity level your seeking. To correct this, the hum. has to hooked up the hot side of the water supply. And the humidifier has to be hooked up when the fan runs and leave the fan run constantly

Jan 12, 2009 | Aprilaire 600 Humidifier

1 Answer

Aprilaire 600: water only runs in "Emergency" Heat mode

When your unit is on normal the outside unit works and the inside only the fan runs. your heat pump does not remove any humidity when it operates so the installation cotractor did not wire it to operate then. you can change the wiring on the humidifier to operate all the time by wiring it to the fan (g) terminal then it should work just turn it all the way to the lowest humidity when you are in cooling mode.

Jan 07, 2009 | Aprilaire 600 Humidifier

3 Answers

Aprilaire 600 - change water panel light stays on

Turn the control knob to the test/reset position untill the change water panel light blinks to reset the change panel timer. Make shure the furnace is running calling for heat.Turn control knob to prior setting after resetting timer. Hope this helps.

Feb 16, 2008 | Aprilaire 600 Humidifier

1 Answer

Aprilaire 600

If the water is always on make shure the 24 volts is hooked up to 24 volts only when the blower is on. Some furnaces have a HUM terminal but make shure it is 24 volts some are 120 volts you must use the transfomer with the AP 600. You may may use a RP50 relay. The setting 5 or 6 is about the avg setting slowly turn down to see if it shuts off .Also make shure the damper is in the winter setting. Hope this helps

Jan 26, 2008 | Aprilaire 600 Humidifier

1 Answer

Aprilaire 400 - Mesh Screen not wet

Not happy either. I bought 3 Aprilaire 400 for my house (3 zones). I picked this style since I have attic installation and did not want to run drains. The first night I expected a major air quality improvement but no change in humidity. I have installed humidifiers before so I know the drastic improvement they make. So I watched for a season and still no humidity improvement. Absolutely nothing at all. Same exact observation as you all described. Only the bottom of the media was wet. I'm dissatisfied with Aprilaire 400. Do not buy! Since I installed humidifiers before and understand them I am converting the Aprilaire 400 to work like a Aprilaire 600. I simply unwired the float sensors, removed the floats/lid and using a knife cut some of the plastic cups so the water would drain well. I also cut open the plastic exit port some too so it wont clog from dust globs. I obviously added drains. HUGE RESULTS. On the very first cycle on the humidity in that zone went from 25 to 48. I am watching carefully. -GK

Dec 31, 2007 | Aprilaire 400 Humidifier

1 Answer

Not getting enough humidity in the air

There are 3 things to check on the humidifier. Check the metal mesh screen, is it wet after the humidistat is call? If it is dry the water solenoid my not be opening or the nozzle is plugged. The circulating fan blows air through the wet screen to add humidity. Does the fan spin when the humidistat is calling? There is an intake and exhaust on the humidifier. Check that the metal was cut out properly when the humidifier was installed to allow air to feely circulate?

Mar 06, 2007 | Aprilaire 600 Humidifier

Not finding what you are looking for?
Aprilaire 600 Humidifier Logo

194 people viewed this question

Ask a Question

Usually answered in minutes!

Top Aprilaire Humidifiers Experts


Level 3 Expert

1033 Answers


Level 3 Expert

1751 Answers

Barrett Palumbo
Barrett Palumbo

Level 2 Expert

1772 Answers

Are you an Aprilaire Humidifier Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides