trane HVAC No Heat xe1100

[Topfoxhole]

My unit works OK in cooling though it can't keep up on a 95+++ day.  When I switch it to heat with the gauges on it when goes into heat mode, the reversing valve works as its supposed to sending the freon the opposite way.  Then all at once after about one to two minutes the head pressure goes all the way to 500 on the gauge and a loud sound (hissing) comes from the compressor.  The compressor stops and it goes to aux heat.  The gauge pressures are about 90 suction and 220 high side when it first starts.  I then turn it to airconditioning and everything is fine.  I am thinking that it may be the reversing valve as when the problem begins the discharge from the comp through the reversing valve stops heating past the valve?  It could be the indoor coil but I don't think so.  Any suggestions?

[JWWebster]

Coils cleaned? Fresh filters?

[Topfoxhole]

Coils are clean and filter is clean. It works in AC no comp stop. 

[JWWebster]

weak coil on the reversing valve maybe?

[Topfoxhole]

I know the initial pressures on the suction is high, but the way it winds the gauge needle just is not right.  I work on 25 ton units that the condenser fan only comes on at 180 and operates full speed at 220. If the fan doesn't come on up goes the pressure.  My outdoor fan runs at 825, or so.  I was thinking a blocked indoor coil but it floes for cooling.  I have the capabilites to yank the indoor coil and check that.  Also I can replace the reversing valve, but don't really want to do either unless I am sure.  When I pull the plug off the reversing valve I can hear the valve closr.  It could be sticking part way when in heat, maybe breaking down.  I will check that.  I forget which way the valve works.  AC or Heat with power.
Thanks

[JWWebster]

It is Ac without power applied to coil> Applying power reverses direction sending condenser air within.

[Topfoxhole]

I will test the coil later today and post the results
Thanks

[Topfoxhole]

I will test the coil later today and post the results. I will suck out some freon to lower the pressures and try that.  Maybe its flooding, but I still wonder why only on heat, weak coil at the reversing valve could allow the valve to partically move blocking off the passage causing back pressure.  I will temp oy the reversing valve and check the change over.
Thanks

[jumptrout51]

Trane systems energize the reversing valve in the cool mode.
Remove the solenoid coil wires from the reversing valve to eliminate any intermittent low voltage signal to the valve.
If you still have the problem I would suspect a sticking reversing valve.

[JWWebster]

You learn something new everyday

[Repair-man]

A stuck TXV in the evaporator will cause the compressor to go on bypass sometimes...just another thought for you to process..you'll need to take some pressure readings with your gauges.

nothing stops a trane, my hind leg

[Topfoxhole]

I got home late tonight so I could not suck (reclaim) any freon, I will do that tomorrow night.  Checked the reversing valve the best that I could. When in cooling mode when I remove the 24 volt power it goes clunk like it I believe it should.  It was in cooling mode.  I do not have very good luck in freeing a sticking reversing vale.  I have wacked them with a rubber hammer.  If anyone has any ideas let me know.  I know at work when a hvac shuts down the rvalve deenergizes and you hear a swhoss.  I don't hear that. When I went to heat when the compressor shuts off because of pressure I hear a swhoss that lasts for what seems like minutes.  I wacked the rvalve and the noise changed slightly.  I have used a strong magnet to try to move one before and it seemed to work.  I will post what I find.  Will check the pressures for the tvx. 
Thanks

[JWWebster]

Would something like Gemline 88 oil free a sticky reversing valve Jumpy?

[jumptrout51]

Would something like Gemline 88 oil free a sticky reversing valve Jumpy?

No.

Topfoxhole: Sounds to me like your problem is in the RV.

[Topfoxhole]

I believe you are correct.  I will try to get one and do the silver work.  I really can't find anything else it could be.  I believe it could also be the problem of not keeping up on a really hot day.  I did notice that when the compressor shuts down that the temps at the reversing valve seem to equalize.
 
Thanks to everyone that responded.  Will let you know how it goes.

George