"York" Ducted Split - Pressures ok in cool, trips on HP in heat

[petem]

Wondering has anyone had this problem:
York ducted split, runs fine in cool mode, pressures and current draw spot on.
Runs for about 4 min on heating and trips on HP.
Evap airflow is OK
Unit is not overcharged.
Unit uses two orifice refrigerant controls, 1 at condenser, 1 at evaporator.
Suspected that rubbish in evap orifice that blocked the orifice in heat mode - nothing.
This one is doing my head in, or maybe it's time to get out of the game.

[Grizzly]

Hi Petem.
It may be a stupid question, but what are the evap (Indoor Unit) Filters like?
Grizzly.

[chemi-cool]

It is blocked somewhere on the high side in the heating mode. look for a cold spot.

[monkey spanners]

Some orifices work as check valves when flow is reversed, maybe one is sticking?

[install monkey]

4 way valve passing/sticking in heating mode?

[petem]

Chemi - Filters perfect
Monkey - not these ones
Install - changed the reversing valve, was leaking through seals
So back to square 1

[install monkey]

after changing 4 way valve- the outdoor tev is clogged

[install monkey]

was the body of the 4 way valve kept cool whilst fitting- may not be fully shifting over in heat mode

[monkey spanners]

There is a trick with small magnets to check rv travel,

http://www.youtube.com/watch?v=bv2yu6WPtiU

[install monkey]

does it show if it has frazzled insides

There is a trick with small magnets to check rv travel,

http://www.youtube.com/watch?v=bv2yu6WPtiU

[petem]

Thanks all:
Install: Yes, rv was kept cool same as all the other hundred reversing valves I have changed ( Not being smart, just that I am methodical and precise in all my work, unlike others we know in the industry)
It can not be the outdoor orifice as the outdoor orifice is now the evaporator, not the condenser.
Monkey: If you are talking about the old reversing valve - No
I still believe that there may be something floating around in the distributor prior to the orifice (acurator) that when in heat mode is restricting flow through the orifice. I pumped the system down yesterday, removed orifice and blew high pressure nitrogen through the suction line, which in reverse mode is the discharge line. Evacuated system and dropped charge - same problem.
Liquid refrigerant could be what is carrying debris to the face of the orifice, where as nitrogen will not lift the debris in order to restrict the orifice. What are your thoughts?
The problem I have is that 2 or 3 people have looked at this unit prior to me and no one has changed anything, just one fridgy increased charge, which I have bought back to correct charge.

[RusBuka]

logjam in gas pipe.

[cool_tech]

Its york. there split systems are rubbish. orrifice faulty.

[petem]

York is rubbish, agree, but the orifice can't be faulty. It is an orifice, and I have checked it. I did not have my verniers with me at the time, but it is about 1.5 - 2.0mm in diameter, and free of any build up.

[petem]

Hey guys, listen up!
We have achieved an end result.
Thanks for all of your help, but there is a lesson in the learning here.
NEVER, EVER listen to people, they are full of ****.
8 hours today and we have a unit that is fixed and working as it should, even though it is York rubbish.
My theory was half right, but after pumping unit down and using high volume high pressure air determined that the restriction/blockage was not in evaporator, so next point of call is the condenser.
Pulled the orifice out of the condenser and guess what.......size 65 orifice. A couple of phone calls later to find old York specs, should be an 85 orifice. Hey, this problem has been here since day 1, but how come only now the unit was tripping on HP? Well, remember I changed the reversing valve at it was leaking. I also found out today that someone changed a burnt out compressor about 18 months to 2 years ago and the system is about 8 years old.All starts to make sense. Original installer dropped part of the original charge to get the unit to run, but how inefficient, and no cooling to compressor through suction line temperature and hence a compressor burn out. Well, no orifices available, so we drill out the 65 to about 80 thou. Evacuate, drop charge and hey presto, all works but trips on HP after about 30 min. Start up again and observe pressures. Had to drop about 750 grams out of unit and it works like a dream. Works a treat on heat, as a piece of York **** does, but not as good on cool, but that is the York design.
So after 3 days we have a result, but I feel for the customer. It's going to cost him dearly, but was never his fault or problem, and remember I was starting to be frowned upon because I couldn't fix it, but have now. This leads to the old problem, TOO many cowboys in our industry.