Crusair No Heat

Forrestkk

Well-Known Member
SILVER Sponsor
May 1, 2021
776
Emerald Coast of Florida
Boat Info
1999 450 Express Bridge
Garmin 5212s, Garmin HD Radar
Raypilot 650
Engines
Cummins 6CTA.8.3M 430 HP
ZF 280-IV Transmissions
Hi All,

Have a 99' 450 EB and have a CrusAir 8000 BTU with an SMX II control panel. Thr unit is located under the master bed. Seems like the reversing valve on the refrigerant isn't working as I select heat and it keeps making cold air.

1. Where is that valve?
2. Can I check for voltage?
3. If no voltage, assuming a board issue?

Thx in advance for the help!
 
Last edited:
Cruiseair valve.jpg
 
I just went through this on my 340. Turned out I had a bad board that would not power my AC water pump.

I have a Dometic DTU 12. Only 4 yrs old. Found it blowing cold air, popped hatch under v berth and found pipes frozen up. Noticed my AC water pump was not running. Knowing my pump had been on its last legs for a while I assumed it was bad and changed it. Still no water and still no heat. Thought it may be reversing valve, so tried tapping on it. No luck. So I tested the voltage on the board where the pump hooks up. No voltage when compressor turned on.

The fix was to remove the wire from the pump hook up on the board and place it on the same hook up as the compressor power. This way whenever the compressor comes on the pump is powered as well. This works if your pump is dedicated to the one ac unit. If you have multiple ac units supplied by one pump this won't work. Now my pump is working and I have heat.

Hope this helps.
 
My current boat came from FL. The heat on a 3-4 year old 16k Dometic Turbo unit was never used. Reversing valve is stuck and will not shift. I can tap on it and 1 in 10 times it will shift and I get heat. One thing you can check and maybe get lucky. There is a small solenoid attached to the reversing valve with 2-wires going to it. Slide it off and check to see if it is functional. It creates a magnetic field in the round opening. Hold a screwdriver in the hole and switch the thermostat to heat and you should see/feel the magnet work. If not, you have a bad solenoid valve that likely cost $10. If it creates the magnetic effect, you have a stuck reversing valve. My AC works great, but no heat from that unit. I have a 12k up front that works great and use a small ceramic hater in the salon.

Bennett
 
@Bayou340 and @bbwhitejr thx for the info.

My raw A/C water pump pumps, no problem, and it feeds all three A/Cs. I know I have good flow as on my boat the forward unit has its own separate drain out of the bow, while the other two both drain into the "main drain" that runs down the port side and exits at the stern.

We are in Florida too, but North West Florida where we do get cool for Jan and Feb, and we use the boat during those times. The boat came from Central Florida, so it probably never saw the heat used. Definitely going to investigate solenoid valve.

Thx!
 
Mine heats but just barely heats. The air coming out of the vent may be a degree or two warmer than the cabin temp. The AC works fine.
 
Heating and cooling are proportional to the ambient water temperature. If the raw water is 40 degrees, the system will struggle to pull heat from the water and essentially not produce warm air. conversely, if the water temp is 92 degrees the system will struggle to put heat into the water and consequently not produce cold air.
 
Our water temp is between 55-60 and it is still struggling. Meanwhile my cockpit heater will heat that area in about 15 minutes. Like it’s not even trying. This is on my list but I was going to push it off until next winter due to the other things that are also on my list.
 
Our water temp is between 55-60 and it is still struggling. Meanwhile my cockpit heater will heat that area in about 15 minutes. Like it’s not even trying. This is on my list but I was going to push it off until next winter due to the other things that are also on my list.

Could be scale, raw water flow, or low refrigerant.

My working units make good heat and we are at about 50 on water temp.
 
Could be scale, raw water flow, or low refrigerant.

My working units make good heat and we are at about 50 on water temp.
On that list, I’m going with low refrigerant, since I have recently descaled the system. the piss stream looks healthy, and the other unit on the same water pump is working great. Just seems odd that a couple of months ago it was cooling great, but it is acting like it’s low refrigerant.

BUT, I didn’t correlate the water temp with the cabin temp until ttmott pointed it out. The unit does seems to keep the cabin temperature the same as the water temp, so maybe there is a bad component and it just isn’t heating at all.
 
On that list, I’m going with low refrigerant, since I have recently descaled the system. the piss stream looks healthy, and the other unit on the same water pump is working great. Just seems odd that a couple of months ago it was cooling great, but it is acting like it’s low refrigerant.

In my experience, it goes from working to not with just a small loss of refrigerant. I can imagine it is even worse on these small units that don't hold that much to begin with.
 
My current boat came from FL. The heat on a 3-4 year old 16k Dometic Turbo unit was never used. Reversing valve is stuck and will not shift. I can tap on it and 1 in 10 times it will shift and I get heat. One thing you can check and maybe get lucky. There is a small solenoid attached to the reversing valve with 2-wires going to it. Slide it off and check to see if it is functional. It creates a magnetic field in the round opening. Hold a screwdriver in the hole and switch the thermostat to heat and you should see/feel the magnet work. If not, you have a bad solenoid valve that likely cost $10. If it creates the magnetic effect, you have a stuck reversing valve. My AC works great, but no heat from that unit. I have a 12k up front that works great and use a small ceramic hater in the salon.

Bennett
I had this exact problem on a unit in my 410 - bad solenoid. Bennett described the screwdriver test perfectly.
 
For fun I measured vent output Temps vs. Water temp today.

Water temp, 50.4F and vent output 98.4F. That is a pretty healthy delta T for a heat pump.
 
Our water temp is between 55-60 and it is still struggling. Meanwhile my cockpit heater will heat that area in about 15 minutes. Like it’s not even trying. This is on my list but I was going to push it off until next winter due to the other things that are also on my list.
You have another issue going on. We are 20 miles north of you and cabin set at 70 plus degrees. No issues, blowing very warm air.
 
Is there anything special to removing the solenoid?
Is it under pressure?
Will we need a recharge afterwards?
Is it a common part?

Thinking we would test the magnetism and if bad, change the solenoid before we call in the experts. Thanks.
The "solenoid" that is serviceable is only the electrical coil. Everything else is sealed in the refrigerant circuit and not serviceable. No recharge needed to remove the coil. Part is common.
 
The "solenoid" that is serviceable is only the electrical coil. Everything else is sealed in the refrigerant circuit and not serviceable. No recharge needed to remove the coil. Part is common.


Thank you! How is it attached? Screws, hex bolt, clips?
 

Forum statistics

Threads
112,942
Messages
1,422,697
Members
60,926
Latest member
dander88
Back
Top