water heater check (one way) valve

[phase3]

I purchased an 89 Catalina 34, hull 885. Having an issue with my Seaward 6 gallon water heater. The check valve for the cold water coming into the water heater keeps exploding if I leave the water heater switch on for too long (~ 1 hour) or if I run the engine for a couple of hours. I replaced 4 valves so far using different brands to make sure its not a one brand issue, but none have worked. I also replaced the pressure release valve, just in case it went bad, but in vain. I asked a professional opinion and was told I need to install an accumulator to fix this problem. I thought the accumulator is only needed if the water pump requires one. Any thoughts?

 

[Don S/V ILLusion]

Remove the check valve - it’s unnecessary.

 

[DayDreamer41]

What is your heater temperature set to? Sounds to me that you are building too much pressure in the heater possibly from developing steam??

 

[Stu Jackson]

I purchased an 89 Catalina 34, hull 885.

Congratulations on your purchase. In addition to this fine forum, I suggest you also check out the Catalina 34 International Association website. Our forum: Main Message Board You can become a respondent on our forum for free, just like here. Lots of boat-specific info.

Re: your check valve - it sounds like it may be in the wrong place. Look at this diagram and check your installation:

Pressurized Freshwater Systems Guide | West Marine

With helpful diagrams and accompanying text, this article from the experts at West Marine will get you up to speed on freshwater pumps and system components.

www.westmarine.com

 

[dlochner]

Remove the check valve - it’s unnecessary.

This is not correct. Without the check valve the heated water will back feed through the cold water system and scald someone.

There should be a temperature and pressure relief valve at the top of the tank with a hose leading down into the bilge. Same as the one on your home HW heater. If this is not functioning correctly, then the tank will over pressurize and the pressure has to go somewhere.

Check and clear the valve by lifting the lever and allowing some water to escape. Or better yet, just replace it, they are not that expensive.

 

[phase3]

Thank you all for your input. I respect all opinions, but I'll have to agree with Dave and will keep the check valve. I attached a picture of what I have. I don't see a temp gauge or a way to set temperature. I may have an older model. I replaced the pressure relief valve myself with a brand new value a few weeks ago.

 

[Stu Jackson]

I don't see a temp gauge or a way to set temperature.

There usually isn't one.

 

[Stu Jackson]

Thank you all for your input. I respect all opinions, but I'll have to agree with Dave and will keep the check valve. I attached a picture of what I have. I don't see a temp gauge or a way to set temperature. I may have an older model. I replaced the pressure relief valve myself with a brand new value a few weeks ago.

The picture doesn't help because we don't know for sure that the left side is COLD IN. If it is, it seems the cv is in the right position. Are you sure it's in in the right direction?

FYI, I still have the flat old black Shurflo check valve in there.

I've had my C34 for 24 years. I have never had the engine create any prv opening. I have motored for 13 hours straight sometimes. It just shouldn't happen. I also recommend turning the electrical heating element off after a half hour or so, enough to get the water hot. 6 gallons will last quite some time. If it cools off, turn it on again for another half hour. It's a management issue.

 

[dlochner]

Wrong type of check valve.

Use a brass or bronze check valve with pipe nipples and attach directly to the water tank. This will keep the intake line protected from the hot water and pressure.

Something like this one from Lowes will work better.

https://www.lowes.com/pd/AMERICAN-VALVE-Check-Valve-Brass-1-2-in-Fnpt-Swing-Check-Valve/1000248917

 

[phase3]

Are you sure it's in in the right direction?

FYI, I still have the flat old black Shurflo check valve in there.

I also recommend turning the electrical heating element off after a half hour or so, enough to get the water hot.

Hi Stu, thanks for all the thoughts. I do have the the check valve flow in the right direct. I learned that the hard way the first time I replaced it lol

The old one I replaced didnt have a visible brand but I believe was a Jabsco based on the design. I did replace it with the only 1/2" I was able to find from Shurflo part no 340-001. I went through 3 of these already, then started to use a less expensive brand. Seems to be holding up if I time the heating element to <30 minutes.

Currently I do exactly what you described when I'm in the slip. I turn the water heater switch and time it for 25-30 minutes, then turn it off, and get nice hot water, which is great. The issue I have is when I'm motor sailing, which I can't control. Like you said, sometimes you have to keep the engine running for hours.

 

[Head Sail]

What do you mean by "exploding". Do you have a picture of the exploded check valve?

 

[phase3]

Wrong type of check valve.

Use a brass or bronze check valve with pipe nipples and attach directly to the water tank. This will keep the intake line protected from the hot water and pressure.

Something like this one from Lowes will work better.

https://www.lowes.com/pd/AMERICAN-VALVE-Check-Valve-Brass-1-2-in-Fnpt-Swing-Check-Valve/1000248917

Thanks Dave, that seems like a logical solution. I will certainly give it a try.

 

[dlochner]

Thanks Dave, that seems like a logical solution. I will certainly give it a try.

One other quick thought. The thermostat, if there is one, is likely part of the AC heating element. It looks like there is a small removable panel on the front of the heater. Behind this may be the heading element and on the element will be a crude thermostat. Don't trust the settings, just know that if you turn it down it will be cooler, I wouldn't count on a 120° setting being 120° but it will be cooler than a 130° setting. If the AC element is not behind the panel, follow the AC wire.

 

[phase3]

One other quick thought. The thermostat, if there is one, is likely part of the AC heating element. It looks like there is a small removable panel on the front of the heater. Behind this may be the heading element and on the element will be a crude thermostat. Don't trust the settings, just know that if you turn it down it will be cooler, I wouldn't count on a 120° setting being 120° but it will be cooler than a 130° setting. If the AC element is not behind the panel, follow the AC wire.

Will do! Thank you all for you help. Much appreciated!