[akjose]

Ameristar HP4A3630 3Ton heat pump

I Shorted out my furnace leads while putting the breaker panel back on, unit was running in heat mode. Now the compressor won't kick on and my defrost board is flashing three times which means "LOW PRESSURE CUT-OFF SWITCH IS OPEN" if I short those leads out I can get the compressor and fan to kick on, if I flip my defrost to manual I can get it to defrost by shorting out the same leads.

Tried a power cycle but didn't do anything. I have 24v in IIRC (it was dark).

I am leaning towards a bad low pressure switch, bad board, or actual low pressure (had a leak last year and had no charge but it never cut it off from running).

Could it be anything else?

I was thinking contactor but since it fired up after having the the pins shorted i threw that out.

I have a single pole contactor with a new board as seen on page 16 here:
http://tranepennohio.com/secure/techdocs/December 2014 3T2.pdf

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[supers05]

You can measure continuity over the low pressure switch with the wires disconnected from it. (power off to the unit) If you read something like OL or a very high ohm reading them it's open. It could be a bad sensor or you could really be low on refrigerant. Only one way to tell, put a pressure gauge on or new sensor.

If it's running when you short across the low pressure switch, then the board is doing its job, and it sounds like the compressor is probably fine. It won't be fine for long if you really have low pressure.

Cheers!

 

[akjose]

Ok. Compressor is off and I am only running inside heat on emergency heat. I will have to check it out this evening after work.


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[roughneck]

Cycle power on the indoor unit and outdoor at the same time. Don't jump the switch out as that can cause damage if there's no refrigerant in the system. Use a meter to see if it's open or closed.
If cycling power doesn't fix the issue put a gauge on it and see if there's pressure.

 

[akjose]

One of the wires on the low pressure switch came off where it was soldered.

For the life of me, I can't find electrical tape in my house to see if this is the actual fix. But it was definitely not making contact. So essentially open. In the meantime, I grounded a body of one capacitor but also checked them and verifiers they are at the proper cap. Voltage in is good and getting 24v to board.

It still could be the reversing valve as I could not engage it without the board allowing it to be on. On the Ameristar junk they are engaged on heat mode rather than cooling like most others.

One of the copper lines coming from the low pressure side has a piece of clear tubing around it and it is melted...like burnt melted. But nothing electrical around it. I guess current could have came through there and grounded. I don't know. Just throwing out options.

This unit was put in less than 18 months ago, in a new house which I no longer have warranty with, but the unit is at least under a 5 year warranty. I've had nothing but problems with the service company and with the unit itself. Called the owner today and he told me to call the office to schedule and they told me they would call him to call me and schedule...and I got no call back from him.


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[supers05]

Likely the the loose connection is the problem, but you've also been fiddling with it.

The plastic is probably the protecting tube on the distribution lines. Completely normal to see a few melted at the ends near the coil. (from the factory)

Typically, engineers want heat pumps to fail to heating in northern areas and cooling in southern areas. These days, you get whatever was cheapest to buy. Personally, I don't think your reversing valve has any problems.

Those kinds of companies are why these sites are so busy....

Cheers!

 

[beenthere]

Ameristar is a private label unit. Its made by Rheem. Rheem energizes the RV in heat mode. That is why your Ameristar does.

 

[akjose]

Likely the the loose connection is the problem, but you've also been fiddling with it.

The plastic is probably the protecting tube on the distribution lines. Completely normal to see a few melted at the ends near the coil. (from the factory)
Typically, engineers want heat pumps to fail to heating in northern areas and cooling in southern areas. These days, you get whatever was cheapest to buy. Personally, I don't think your reversing valve has any problems.
Those kinds of companies are why these sites are so busy....
Cheers!

Only reason I say reversing valve is because when I had the emergency heat on, one of the outside lines was condensing. Of course I am not sure it it opens and allows the flow to flow normally.

Last year our defrost board went out, reversing valve was stuck and got replaced among other issues....to be continued at bottom

Company said they would be out Monday to fix it and I told them about the wire ahead of time.

My gauges came in but I got out of work late and I have to get up early tomorrow so more self diagnosis will have to wait.

I think Ameristar is marketed under Trane IIRC.

...continued from above(I wanted to stay on topic) breaker tripped at some point for the emergency heat because they had put in a 20kw heater instead of 15kw which it was wired for, we had a leak at some point and the system was still running (bad defrost board design I think). I had 4 months of 7500kwh used each month all Between about 7 service calls. Also I did my own measurements and load calves and found out the whole system is undersized, as well as having restricted returns (it was blowing no air out of the vents on heat mode), I had to argue with them about the returns and they finally cut more in. But I still have a restrictive. Rant off.


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[crabjoe]

Ameristar is Builder's grade American Standard. Ameristar, American Standard, and Trane all owned by Ingersoll Rand.

 

[beenthere]

Under sized for heating or for air conditioning?

 

[akjose]

Under sized for heating or for air conditioning?

Both
Can barely maintain 70 in mild summer we just had. We typically like it 68 but "it was designed for 74". Leave a door open too long or have more than 5 people in the main living area and it gets up to 78 and can't drop back down until the sun goes down.
Heating can barely maintain 71 and takes about 2 hours to change the temp 1 degree. We have a non programmable thermostat As I am afraid to change the temp any at all while we aren't here because it would take all day to get back up to temp.


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[jimn]

I am jealous. I wish I lived somewhere electricity was cheap enough to cool my house to 70 degrees. In the northeast you don't want to think about cooling much below 75.

Sorry can't help with your issue though

 

[akjose]

Pressure is around 138 psi on both sides while off.

 

[beenthere]

Pressure is around 138 psi on both sides while off.

So it was about 48°F outside when you checked the pressure.

 

[akjose]

So it was about 48°F outside when you checked the pressure.

Yes


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[beenthere]

Then it has enough charge in it that it isn't a low charge issue.

 

[akjose]

Ok. Thank you. I figured it was at least above the pressure required to trip the low pressure switch.

I am hoping it is only the low pressure switch issue. I will hopefully know more on Monday.

I would replace the switch myself but I think it is soldered on. Could be wrong but I see no other way to get it off. Any ideas?

Switch/sensor, whatever you want to call it.


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[supers05]

You can get threaded versions. You put it on the service port. Get a swivel tee with it. Don't forget to put the Schrader core in. 😎

Cheers!

 

[akjose]

Lol. I could see myself doing that and Losing half the charge.
Any idea what pressure it needs to be for? Or are they all pretty much the same? Is it considered a switch or a sensor? Or even a specific model?


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[akjose]

Service guy here and gone. Said he was going to have to evacuate and replace since the switch is brazed on, or he could bypass it but didn't want to do that and it would be my decision. I told him about the above aftermarket switch on the service port and he liked that idea. He is checking with REMichel in town to see if they have anything. He nor I want to evacuate it with it being so cold out now and after all the problems we've had before.

Best part is, I told the owner what I had found when I called to schedule and he never relayed any of that info to the tech. I was expecting to have a switch in hand and ready to evacuate the system and be done with but nope. Another great service call.


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