GrandAire heat pump blower won't shut off

[TroyL]

I have a Grandaire heat pump it is a model WJA4
The blower will not shut off unless I trip the breaker.The thermostat is set to auto and the blower runs continuously doesn't matter if it's set heat of cool. I would appreciate all help and troubling shooting tips
Thanks

 

[BillK]

Could be the thermostat. If you turn the thermostat to "off" will the blower stop ? Or disconnect it completely ? Otherwise you will need the manual and a wiring diagram to further troubleshoot.

 

[Done That]

As Bill said, disconnect the Tstat completly and then restore power to the unit. If the blower is still on you probably have a welded relay in the package unit. Otherwise a welded relay in the thermostat can be the culprit. You need to determine which end of the system is causing the issue by process of elimination.

 

[OccupantRJ]

I had one do that this weekend. It was a sequencer in the heat strip area that had come apart, turning from normally open connection to normally closed when it broke. $10 fixed it. Look at some videos on YouTube for how they work.

 

[TroyL]

I unhooked the thermostat and it keeps running so I assume I need to pull the outside panel off and start checking there

 

[OccupantRJ]

As someone else said, it may very well be the fan relay acting up. I pointed out the sequencer issue I ran into because it was a weird event. You could try tapping on the surface next to the fan relay with an object to see if the vibration causes the relay to release and shut the fan off. If it does, replace the relay. Past this, it likely is circuit tracing time unless you see a broken wire or wire terminal. If there is a diagram in the unit, I usually take a picture of it then expand it out on my IPad so The wiring is easier to trace for my old eyes.

 

[acmikee]

disconnect your "R" wire that will eliminate the tsat and the wire. if its still on then the control board probably need to be replaced..

 

[Jim greengo]

Do you have the switch turned to on instead of auto on the thermostat?
Maybe try pulling green wire off of stat.
Is there a high limit switch someplace that could be stuck?

 

[Jim greengo]

I had the same problem!

What did you do to solve it?

 

[TroyL]

I unhooked the green wire a couple days ago at the thermostat and blower kept running will try the red wire tonight and see if that works

 

[Done That]

Document I see on the web says a WJA4 is a packaged AC unit, with option to add electric heat....that's not a heat pump. It's a Carrier/ICP unit, private branded for Baker Distributing I beleive.

I don't see any control board in it, just some heater relay(s) depending on how many kw of electric heat was field installed.

When the blower is stuck on is it putting out heat? or just blower air?

 

[TroyL]

It's putting out just blower air now it will blow out hot or cold depending on what the thermostat is call for

 

[TroyL]

So here is a pic of what is in the unit the relay at the top right corner is for the a.c. Compressor not sure which one is for the blower

 

[TroyL]

It is just blower air

 

[Done That]

The ones in the left are the heat relays, plus the little tan board is a rectifier pcb I believe.

I'm thinking a heater limit or relay is stuck and keeping the blower on as a safety so it doesn't overtemp.

I'm not up to speed enough in those to offer much help. Going to need a meter and wiring diagram to sort it. Follow the wires back from the blower and start there.

 

[TroyL]

The thermostat wires all have 28 volts outside at the unit depending on what I have the thermostat set at heat or air except the brown wires they never have any voltage and whenI I had the heat set at the thermostat each of these had 110 volts

 

[TroyL]

So is this relay here maybe bad one of the brown wires go to the relay the other to the blower

 

[Done That]

That tan little board snaps onto the relay below it.

If you remove the thermostat and ensure no inputs coming from that wiring then you should be able to verify the relay is stuck if the blower remains on. Might be able to swap those two relays as a simple test, doubt both are bad at the same time.

 

[Done That]

Second picture in your first post above looks to be a sequencer (two yellow wires) simple metallic timer/switch. This is the item an earlier poster said caused same issue in his unit.

 

[OccupantRJ]

http://www.grandaireac.com/wp-content/uploads/2018/04/WJA4-42655170800.pdf

Looking at the diagram in this link, why does the indoor fan motor show low voltage wiring going directly to the motor? Is there a fan relay attached directly to the motor? Or is there a relay inside the motor itself? I have not run into this on an HVAC diagram before. New to me. Is there something I am not seeing? The legend does not call out a fan relay either. The heat relays do not show a fan relay as part of them either. Normally when heat strips are activated, the first sequencer in line normally turns the fan on.

 

[TroyL]

Do you have the part number for the sequencer and did you buy it local or on the net

 

[OccupantRJ]

Not sure who the question is directed to, but if me, I got my sequencer at a local HVAC supply that has no issue selling to the homeowner or handyman. Mine was a double stack unit where the first stage turned the fan on first, then the heat strip. When the control voltage to it ceases, it turns off the heat strip first, then the fan, to allow some cool down of the air stream. I don’t remember the number of mine right off. They are available in a selection of functions and timings. The M numbers on the sequencer determine when each stage of the sequencer does it’s thing. Timings are marked on the units.

 

[TroyL]

Thank You RJ I'll have to see if I can get it online been to some of the HVAC supply stores here and they only sell to HVAC companies

 

[OccupantRJ]

Troy, in the picture below, the small green wire should be what turns the fan on from the thermostat. Shut the unit down by shutting off power to it, and then disconnect this small green 24 volt wire connection. Keep ends from touching anything else. Turn unit back on and see if fan then runs. Give it at least 6 timed minutes before doing anything else. Let us know what it does. You could possibly have a shorted control cable wiring connection keeping the fan on.

Also examine the control wiring coming to the unit from the house. Weed trimmers are control wiring killers.

 

[TroyL]

What set of numbers on this sequencer is the part number

 

[LS6 Tommy]

What set of numbers on this sequencer is the part number

That's not a sequencer. It's a limit switch. L160-40F is the universal part number.

Tommy

 

[TroyL]

Does anyone know who the manufacture. Of this is

 

[Done That]

Does anyone know who the manufacture. Of this is

Therm-o-disc 60tx series

 

[TroyL]

I have put in the numbers in search and nothing comes back that's close what web sites have you all used I've tried Google Amazon ebay and have not found the right one

 

[LS6 Tommy]

https://www.ebay.com/itm/3F01-160-F...=item544556da9e:g:mQUAAOSwR9tboCZy:rk:17:pf:0

https://www.amazon.com/dp/B00IDFFVCG/?tag=atomicindus08-20

https://www.amazon.com/dp/B00QW283BS/?tag=atomicindus08-20

Tommy