Hi Louis~

If you are sure that the compressor is running the following are possible:

• Your gauge hoses are not properly depressing the needle valve/s in the service fitting/s…
• The reversing valve is stuck in the halfway position, which would be indicated by the suction line (larger of the two) back to the compressor being hot…
• The compressor valves are bad and not allowing it to pump refrigerant…No lines hot…
• The compressor is actually NOT running…No lines hot…

You are describing equalized pressures & they would likely be the same with the unit completely off…

The pressures listed on the label are for testing the unit for leaks with nitrogen…They are not an indication of operating pressures…

In your cabin/water temps I might expect a low side of around 70 and the high side around 210-230 with a pumping compressor…Both will change with cabin & water temp…

Steve~

Post edited 12:46 pm – July 21, 2011 by Steve Pooler

Louis said:

Hi Steve, thank you very much. At rest, I am getting equal pressures. When we turn on the AC, they do change. When I disconnect the high pressure cut out switch the system disengages...It should… When I disconnect the low pressure switch nothing happens.…It will shut down eventually but there is a delay…and several re-start attempts…Both lines are HOT. So, from what you are descriing it sounds like a reversing valve. Can you tell me how I can test this, what it looks like and where it may be.

 

The reversing valve has three tubes into the top and one out the bottom…It also has an electro-magnetic coil with two wires connected…When energized it pulls an internal slide the opposite direction thus re-directing the flow of refrigerant backwards thru the system…It's why they are called Reverse Cycle…The refrigerant reverses direction…

 

To try to free it up….First I would remove the nut holding that coil on the slide….Then energize the heat mode with a setpoint of 99 and pressing the heat button on the SMX II control…With the unit running pull that coil off and slide it back on several times (don't leave it off long or it will overheat itself) Do this while watching the gauges….

 

If you are successful you will hear the valve make a big woosh sound when it does break loose, and the gauges will show the response with more normal pressures….

 

If that does not work…Then try the same with the pump wire/s disconnected, or shut it off at the breaker (if it has one, but being a 270 with only one A/C system it probably won''t) Don't just shut off the thru hull either…We don''t want to melt the pump head by running it without water…

 

Disconnecting the pump will hopefully help build enough head pressure and maybe force the internal slide to the opposite position….Once you have it moving… Exercise it several times…This helps lube it with the internal oil that moves around with the refrigerant…

 

And please…Contrary to what you might read, or hear elsewhere…Do Not Tap or Bang on the valve…It''s only likely to dent it, and then it will never slide !!!

 

Let me know how it go''s  

 

Steve~

Just disconnect the pump wire Lou…

Steve~

Louis said:

Hi Steve, I have tried your first test of diconnecting the coil and sliding back and forth with the heat at 99..no luck yet. I am not sure how you disconnect the pump. Are they the aires on top of the whute cylinder that look sort of like an automotive accumulator?

If this does not work, any other suggestions?

 

Thanks Lou

Wasn't sure what you were asking yesterday when reading/typing on my phone Lou…

I think you are asking about wires on an accumulator…No…Those won't be pump wires…

Either follow the wire from the pump to where it connects, or take the top of the electrical box cover off of the unit…inside there will be a terminal strip with pump connections clearly labeled…You only need to disconnect one wire to disable the pump.

Steve~

Lou,

Were you doing the coil trick with the pump disconnected ?…If so, then it's not good news…

A reversing valve assembly is $435.00 and a compressor is $615.00…

Either or both could be bad, and we have no way to tell without replacing one or both…Also, a bad reversing valve dumping that hot gas back into the compressor could have done damage to the compressor that may not show for a month or so after replacing the valve…

Either/Both job/s require removing the unit to a bench, recovering refrigerant, cutting out old part/s, soldering in new part/s. evacuating the system, re-charging with refrigerant, test for leaks at new solder joints, then install unit & test…

If you only do the valve & it works, fine but…Like I mentioned, it's very possible that damage was done to the compressor and it too will fail soon with the same symptoms (I've seen it happen many times)…Then you are faced with the whole job again with similar labor charges…

It's best to go ahead & do both at the same time to avoid the chance of the compressor failing soon…But if you do both, you still end up with a unit that has an old fan motor, & the possibility that it could have junk in the refrigerant system from soldering etc that could clog the capillary tube (another reason for failure) & no factory warranty…

A new unit will have Warranty, a More powerful blower, It's smaller, quieter, more efficient, weighs less, drains condensate better, has new "Green" refrigerant of the future, plus a pan/base that is made out of composite material that won't rust…

Steve~