A/C Condenser Compressor cycles quickly....

[sgharford]

I'm sure this question has been asked a thousand times, but I have to ask again as I have a HVAC tech coming out in next couple of days to look at.

I just launched boat few days ago and tested out systems, including A/C system. The compressor on a 10 year old Dometic R22 16,000 BTU condenser is cycling on for about 3-7 seconds, then shuts off for about 10 - 20 seconds, then on again for 3-7 seconds, repeat. Does this wether in heating or cooling mode (with temp set to activate compressor in each mode, appropriately). I'm assuming it's going off on the low pressure switch and needs a charge (not charged since replaced 10 years ago). I don't see a capacitor to start the compressor, but could be hidden. Guessing it could be that too but it does sound like compressor is actually running for those 3-7 seconds, which if is the case, not the capacitor. What do you guys think is causing the compressor cycling?

 

[zigzag930]

Check water flow. Probably #1 reason for short cycling as head pressures trip the HP switch

 

[Pascal]

How is the water flow? What controls do you have ?

If it was tripping on low or high pressure, it wouldn’t restart and cycle indefinitely. Some controls allows for a couple of errors and restart before shutting down.

 

[sgharford]

Waterflow looks good, although the raw water pump is t'd off to two separate 16,000 BTU condensers which then discharge into a single discharge sea chest. So perhaps I should put a pair of vice crips on hose to good unit (which I'll leave off) and see if water still coming out as it would be forced through unit in question only. I did not realize these condensers had water flow switches. It seems impossible to find a parts diagram for them, guessing they do a good job of protecting their dealers. Anybody know where the waterflow switch is located on these (Dometic / Marine Air Specialist model CSM16K/1, Serial Number: 82599251) so that I can check out switch operation if waterflow looks good?

The controls are Coastal Climate FX-1. Been working great for about 5 years now.

 

[cww]

Waterflow looks good, although the raw water pump is t'd off to two separate 16,000 BTU condensers which then discharge into a single discharge sea chest. So perhaps I should put a pair of vice crips on hose to good unit (which I'll leave off) and see if water still coming out as it would be forced through unit in question only. I did not realize these condensers had water flow switches. It seems impossible to find a parts diagram for them, guessing they do a good job of protecting their dealers. Anybody know where the waterflow switch is located on these (Dometic / Marine Air Specialist model CSM16K/1, Serial Number: 82599251) so that I can check out switch operation if waterflow looks good?

The controls are Coastal Climate FX-1. Been working great for about 5 years now.

Most of them don't have flow switches, but all of them have high pressure switches that will almost immediately trigger and shut the unit down when the compressors kicks on without cooling water. Same difference really.

 

[Pascal]

Pull the hose off the sea chest and put it in a bucket to check for flow.

I doubt these have water flow switches. I know chillers have them on the chilled water loop and they can be a pita. On regular condensers the high pressure switches will trip as soon as pressure gets too high and will prevent damage.

 

[sgharford]

Not the water flow, put vice grips on hose to 2nd good condenser to cut off flow to that one and water still pouring out sea chest. I’m watching the amp meter built into Hatteras electrical panel and it jumps and stays at about same amperage as good condensing unit for the few seconds it does run, so doesn’t look like compressor is locked up. Without proper HVAC tools and know how, think I will have to wait on tech. Will report back what it is when I find out.

 

[Briankinley2004]

I would guess next culprit is low refrigerant but you need gauges to check that.

 

[cww]

Not the water flow, put vice grips on hose to 2nd good condenser to cut off flow to that one and water still pouring out sea chest. I’m watching the amp meter built into Hatteras electrical panel and it jumps and stays at about same amperage as good condensing unit for the few seconds it does run, so doesn’t look like compressor is locked up. Without proper HVAC tools and know how, think I will have to wait on tech. Will report back what it is when I find out.

Here's where it gets fun. Almost all the companies you call will try and sell you an entire new condensing unit from cruisair for almost $6k. But you can get the compressor, not the whole unit, for a few hundred dollars from grainger or other places online, and have it installed in your condensing unit by any ac company for a few hundred more dollars if you're willing to bring it to them. If you don't want to mess with it and want them to come out to the boat, my experience is almost any company will figure out a way to get $1k out of you for an onsite call. But either way you still save like $5k. There's another recent thread where somebody just posted the part numbers and the link to buy the drop-in replacement compressors for most of these units.

 

[sgharford]

I hear what you are saying above. HVAC companies love to protect their craft and I find usually recommend worst case, most expensive fix (ie replacing unit). Even if it's a charge of 1 lb of the banned no where to be found scary ozone depleting R-22 I know I'm going to get hit with a $1,000 invoice. Sad to admit, but I sold commercial HVAC equipment for six years for a major manufacturer, but I don't know how to work on them. The good condenser is original (47 years old) and never been charged, at least in my 15 years of ownership. There has been little reason for me to invest in tools and know how as result. But I am starting to get the itch...

 

[cww]

I hear what you are saying above. HVAC companies love to protect their craft and I find usually recommend worst case, most expensive fix (ie replacing unit). Even if it's a charge of 1 lb of the banned no where to be found scary ozone depleting R-22 I know I'm going to get hit with a $1,000 invoice. Sad to admit, but I sold commercial HVAC equipment for six years for a major manufacturer, but I don't know how to work on them. The good condenser is original (47 years old) and never been charged, at least in my 15 years of ownership. There has been little reason for me to invest in tools and know how as result. But I am starting to get the itch...

You can easily buy 5-gallon jugs of R22 on eBay as long as you're willing to sign the certification saying it's either for resale or for installation by a certified a/c tech. With the understanding that it's unlikely the EPA has a spy satellite hovering over your boat, but some may have a moral objection to this. Once you do that, get a set of manifold gauges and adapters and recharging the system is very easy. There are tons of videos on youtube, or you can get the original cruisair factory manuals off the documents sections of the sea-ray forum that have detailed charging instructions. Or just buy the compressor and have a tech install it. They have to braze it in with a torch, one of those things they do all the time but was over my head and I'd probably burn myself or drop molten whatever into the compressor and ruin it, so I left that part to them when I did this on my old boat.

 

[rwaldrop13]

There's a similar discussion on here in another thread - If the compressor is coming on, it's probably not the start-run capacitor. My experience with those is that you can hear the motor trying to start but not getting past the hum. If it's low refrigerant, and you suspect a leak, I wouldn't just keep recharging it - That will eventually lead to contamination in the system and a seized compressor. If it's a single-piece unit and accessible, buy a jug of leak-check bubble solution at CC Dixon, or Grainger. Don't be steered in to leak dye - That WILL turn acidic and the acid will eat the compressor seals. It's just a service provider trying to make repeat business. If a vendor wants to leak-check the system, ask them if they use dry nitrogen. That's the only truly effective to pressurize it, then spray the bubble solution at any joints/elbows/valves. In my former life as a service manager in truck/trailer refrigeration and A/C, we had a love/hate relationship with customers who would go to the autoparts store and buy the DIY charging kits with leak dye - Usually we loved that they were trying to resolve it themselves, but hated handing them the bill.

 

[sgharford]

So this did turn out to be a low refrigerant charge. Took 12 ounces R22 at $10.75/ounce. That plus service and sales tax led to a $732 invoice. Potential problem still there as no mention of finding or repairing a leak in the system. Hopefully it holds. Next time I think I will take the plunge to pick up a manifold and small tank R22. Question - When charging R22, does the refrigerant in the tank you purchase to recharge typically have the compressor oil already in it or do you have to add separately?

 

[zigzag930]

Typically, the oil does not leak out with the refrigerant, so you can top off the charge without having to worry about adding oil.

Pretty simple to charge yourself once you have a gauge set, R22 and the rotary valve tool (or equivalent) to open the charging port. Don't forget, you turn it clockwise to open and counter-clockwise to seal it back.

J