AC System 'Reversing Valve' stuck. Help?

[stormchaser]

Well, this blows. We were getting LP on once of our 4 Marine Air (yes, Marine Air, not CruiseAir) units so we had them looked at. They found it to be lwo on freon, not a big deal. But while there we ahd them service all the units only to discover a BIG but unknown problem with the salon unit.

Until jsut the week before last, we never needed heat so never knew we had a problem. The Salon unit puts out really good COLD (in AC mdoe) but almsot no heat (lukewarm at best). The others pump out lots of heat (so we know its not just low water temps).

So, what did they find? They found that the "reversing valve" is stuck. this is likely because the installer of the units did not do the initial install right. It seems they didnt install an inline filter to catch crap in the lines and likely didn't blwo out the lines to clear any junk in them...so now the reversing valve is junked up and will not "close all the way". They confirmed this with their gauges. in AC mdoe pressures look good, but in Heat mode, it looks almost like there are two high sides...thus indicating a stuck reversing valve.

So...what they say is "replace the system"...that it would cost more to tear the system apart, replace the valve, and put it all back together. Argh! Thousands of dollars in damage due to INCOMPETANCE...and of course the original installer is no longer in business according to the pervious owner.

So...anyone ran into this before and been able to get the valve "unstuck"? The tech said that if the stuff passes through somehow, it will end up in the receiver/dryer and likely be ok...the problem is how to get it unstuck jsut once? They said to try fliping back and forth from heat to AC a bunch of times over a day or two and it MIGHT work loose. Any other thoughts or suggestions?

 

[krush]

You actually have a few options. If the AC guy says replace the whole system, then i suggest you never let him on your boat again.

First, try banging on the thing--and whilst you bang on it, try to cycle it back and forth between cool and heat. Move the wires around manually to do it--most HVAC systems use 24v AC to do all the controls. You have to do this with the compressor on, as the valve uses pressure to actually change positions (the solenoid just opens up "bypass holes" that let the pressure do the valve manipulation--look it up to see how it works via Google). It's usually a good idea to always have a set of gauges hooked up so you can see what is going down and make sure you don't rocket the head pressure.

Second, you can isolate the valve and try flushing it with solvent to clean it out. This means opening the system, unless you have isolation valves (unlikely).

Third, replace the valve. They usually aren't that expensive. You'll need to evacuate the system, install the new valve (solder in), install a dryer/filter, vacuum out the system, recharge.

I'd try banging it and cycling it first, you may get lucky.

 

[MikeP]

Neighbor on our previous dock in NY had exactly the same problem which was solved using the "bang on it" method Krush described. Of course, if it's truly some sort of installation problem that may not work.

But I totally agree with Krush - I think the ac guy is trying to sell you a bill of goods. The part can be replaced as he points out; there could NEVER be a need to replace the entire system just for a bad reversing valve.

To keep the reversing valves working properly, it is recommended to occasionally run the units on heat, even when you don't need it. That way they get exercised and don't jam in one position.

 

[captddis]

I usually remove the compressor wire then put power to the rev valve, then remove power tap valve, reapply power or do it at the t stat switch with comp off. It will free up. The rev valve is 115 volt on the marine units.

 

[Boatsb]

The reversing valve is factory installed therefore the only thing the installer could have done was to contaminate the system. If that is the problem replace it and have a new one installed by a competent installer. The whole system will not be screwed up by that one valve since you have said it was working great on AC.

Marine air, Cruisair and others build and wire the controllers so the installation is almost idiot proof. All the need to do is plumb it and plug in harnesses.

 

[krush]

http://hvac-talk.com/vbb/showthread.php?t=185626

 

[stormchaser]

Well, two different AC places said the same thing...normally costs more to have them replace the valve than to replace the whole system. Both the local CruiseAir dealer and the local Marine Air dealer said the same thing. But, I definitely am hopeful I can free it up. I asked them about banging on it and they said they are tucked away and inaccessible...but he did give a good description...the size of a roll of quarters with three pipes coming off the top and one at the bottom. I'll, of course try to free it up. Anyone know which wires to mess with to force it to actuate/reverse without having to change the thermostat?

 

[captddis]

on Cruisair the rev valve is the blue wire, BUT marine air has a different code.
Locate the rev valve, there are 2 wires that come off of the valve one is neutral and one is hot. Without power applied the valve is in the cool mode when power is applied it should click and then it is in heat mode. Be paitent and work it . I have yet to have a valve that I could not get to free up.

 

[SKYCHENEY]

Get a helper and have them work the thermostat back and forth while you tap on the valve. That way you don't have to mess with the wiring.

 

[bobk]

Well, two different AC places said the same thing...normally costs more to have them replace the valve than to replace the whole system. Both the local CruiseAir dealer and the local Marine Air dealer said the same thing. But, I definitely am hopeful I can free it up. I asked them about banging on it and they said they are tucked away and inaccessible...but he did give a good description...the size of a roll of quarters with three pipes coming off the top and one at the bottom. I'll, of course try to free it up. Anyone know which wires to mess with to force it to actuate/reverse without having to change the thermostat?

Dave, is your AC guy in Baltimore named Woody? If so, I'd trust him. If not, look him up for another opinion.

Bob

 

[stormchaser]

Dave, is your AC guy in Baltimore named Woody? If so, I'd trust him. If not, look him up for another opinion.

Bob

I didn't catch their names. But the first one was Annapolis CruiseAir (the local CruiseAir dealer) and the second company was Ocean Options (the local Marine Air dealer)...bioth said you are FUBAR'd if the valve gets stuck and won't unstick itself.

 

[krush]

Cycling the valve without the compressor on may unstick it, but the actually valve internals move using line pressure. This is why I said you may need to have the compressor running to be successful.

Just another thing to add to the monthly checklist, switch from AC to heat.

 

[Jaxfishgyd]

I should of known better than read this thread....

I tried our units today,,

Our staterooms unit came on and it putting out hot air... Now the saloon unit doesn't... A/C comes on but not the heating side.

Am sure it's Krush's fault somehow.

Damn, still haven't figured out the defective electrical outlet in the master stateroom from last week ..

 

[krush]

Am sure it's Krush's fault somehow.

That's what they say at work too LOL

 

[bobk]

I didn't catch their names. But the first one was Annapolis CruiseAir (the local CruiseAir dealer) and the second company was Ocean Options (the local Marine Air dealer)...bioth said you are FUBAR'd if the valve gets stuck and won't unstick itself.

Nonethless, if it were me, I'd give Woody a call at 410-752-2870, 0r cell 443-831-0556. He is an independant guy and does almost all of the AC work at BYC and many other clubs and marinas in the area.

Bob

 

[J's Dream]

...both said you are FUBAR'd if the valve gets stuck and won't unstick itself.

Dave,

What was the outcome of this? I am having trouble similar to yours...won't switch over to heat.

Can someone post a pic of the reversing valve so I know what to tap with a hammer?

Thanks,
Jason

 

[stormchaser]

Mine is still stuck, but I only tried tapping on it a couple of times along with intermittently applying/removing the poer to the valve. It has quick connects on it, so it's easy to remove the wire then put it back. It does CLICK, but it never seems to start producing heat and the compressor clicks off within less than a minute of coming on. Ugh...but I'll keep banging on it and see what happens. Its actually pretty hard to miss. 3 tubes coming in the bottom, 1 out the top with 2 electrical connections...but I'll try to snag a pic next time Im onboard...

 

[Boatsb]

This is a bare valve. Yours may be painted but will be similar.


http://freepoolheat.com/images/rev640.jpg

 

[stormchaser]

That's pretty much it, but mine is white. Wish it was easier to replace...seems like a common failure...you'd think they'd make them easily replaceable.

 

[thoward]

I hate to say it but even my brother(an ac tech) says it is likely as cheap to replace the unit as it is to start changing valves. Often 1 thing leads to another and then you are really screwed. At $90 per hour you can get behind very quickly.