Fresh Water Problem

J

Jims380DA

Member
Mar 5, 2007
286
CT
Boat Info
2000 Sea Ray 380DA, Kohler Gen
Engines
8.1L 496 MerCruiser
When using the COLD water on any faucet of the boat, I get a blast of scorching hot water through the cold water line. It has been doing this for a few seasons now and affraid of the kids now getting burned. Has anyone ever experienced this problem before?
 
Sounds like someone installed a bypass on the water heater and and the valve is leaking into the cold water.

That's the first place I would look. It's got to be coming from the water heater.
 
Jim:

The HWH on the 380 has three lines attached to it. There are Two cold "IN" and one hot "OUT" The first cold "IN" fills the HWH. The second cold "IN" mixes with the hot "OUT" to regulate the Hot temperature through a mixing valve. It's possible that your mixing valve is malfunctioning and letting some pure hot feed into the cold side.


The first thing I would do is roatate the mixing valve "full on" and "full off" a few times to maybe clear it out. If that doesn't work, you may have to replace the mixing valve.

Below is picture of my 380 HWH in bypass mode. The mixing valve is visible in the pic....hope this helps....


http://www.byowneryachts.com/forums/phpBB2/files/copy_of_100_3460-1_390.jpg





Good luck....
 
I have an older ( 1995) dancer.....with no mixing valve........but it does have a "check valve " on the cold in.....to prevent this problem.

Maybe check that valve too..........
 
On my 260 (and previous boats), I would get warm/hot water for 1-2 seconds on the COLD line, after running the engines for a while. This only happens after running engines, and I have always considered it normal. I cannot say it's scorching hot, but mentioning it just in case.

Esteban
 
thanks for the advise guys. Dominic, I do have the same valve on my 380. what is Full on and full off?
 
Jim:

Basically, what I'm saying is to turn the valve full clockwise and full counter clockwise a few times. Without knowing exactly how the inside of the valve is designed, you may have a build up of "crud" that may loosen "something" up inside the valve. Like with any valve (Seacocks come to mind) it's good practice to "excersize" them....
 
Dominic...."Crud" in a Searay........BLASPHAMY........... :smt101
perhaps some mis placed dirt but "crud"..............never! :smt018
 
The amount of "crud", from what I'm told, is directly proportional to the Captain's height.... :grin: ....
 
Jims380DA said:
When using the COLD water on any faucet of the boat, I get a blast of scorching hot water through the cold water line. It has been doing this for a few seasons now and affraid of the kids now getting burned. Has anyone ever experienced this problem before?
Click to expand...

inside " cold water in" fitting on water heater should be a check valve to let cold water in to heater but preventing back-feeding
to cold line. If check valve is removed or installed on " out" side of heater you may experience hot water from cold side of faucet.
Those "fancy" by-pass valves installed on some boats are to regulate max temperature of water coming from heater.
 
Greetings all, I have the same problem and after investigation the check valve on the inlet of the atwood water heater is not working.

When I disconected the inlet line from the brass fitting that screws into the tank, there was the remains of a small plastic piece which looked to hold a ball bearing at one point in time. I assume this was the check valve.

I've searched the local marine & hardware stores for this and have not found anything close to original equipment.

Anyone know where to get one of these "Check Valves"?

I did find a 1/2" PVC spring check valve that could be used but would prefer to keep to original parts.

Thanks
 
Giddy Up said:
Greetings all, I have the same problem and after investigation the check valve on the inlet of the atwood water heater is not working.

When I disconected the inlet line from the brass fitting that screws into the tank, there was the remains of a small plastic piece which looked to hold a ball bearing at one point in time. I assume this was the check valve.

I've searched the local marine & hardware stores for this and have not found anything close to original equipment.

Anyone know where to get one of these "Check Valves"?

I did find a 1/2" PVC spring check valve that could be used but would prefer to keep to original parts.

Thanks
Click to expand...

your SR dealer should have them, they maybe separate or build right inside fitting and replace as assembly
the proper way to install them is to let cold water in and not mixing back to cold water. If you buy check valve only, there is an arrow shoving water flow.
i do not recommend to put other kind check valves because water pump is not very powerful and may not fill up water heater
 
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