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.