98 model 405 hot water heater

[Serendipity]

Captains,

It would appear my hot water heater is leaking. Pictures attached:)

It appears water is spraying from the metal relief valve and it still has the plastic drain valve as shown in the pictures to the left.

If I leave the pressure washer on, it will drain the fresh water tank. Boat had 335 hours on it 2 years ago and it has 450 on it now, so low hours.

This is the Seaward brand and probably what came with the boat.

So here are my questions?
In the forums, some people are replacing both valves with brass versions.
Does this solve the leaking pending the weld has not spilt?
Or would you just replace the whole unit since it is 22 years old.
Is there a tankless version I could go back with instead?
Is the Seaward brand okay?
Do you have another brand that seems to hold up better?

The pressure washer appears to rattle on the board underneath the aft cabin bed, but in my opinion, it appears the screws have just backed out some. So I am going to tighten them down and check the noise.
How long do these last and is it wise to replace both the pressure washer and hot water heater at the same time.

I will be replacing these myself as I have been a automobile service manager for 25 years. I love tinkering and repairing issues gents.

Your thoughts please and this is a 1998 405

[tomschauer]

If it is leaking from the relief valve and nowhere else, there is no reason to replace the entire heater. Replace the relief valve. If the water it screaming hot, you may need to replace the thermostat also, as the relief valve opens on pressure and temperature.
These parts have nothing to do with hours on the boat, but more to do with years of age.
I replaced the relief valve and thermostats on my 1998 two season ago, all has been well since.

[Serendipity]

Tom,

That sounds like a plan on replacing the valves and I will replace the thermostats regardless. The water is very hot and where are the thermostats located that I need to replace please?

[AaHubb]

I too had a leaking relief valve last year. After removing it I found it was fouled by green crud buildup and wouldn't close all the way. A good soak in vinegar cleaned it up and now works fine.
..Aaron

[Tireless]

I agree with Tom. Change the pressure relief valve and other parts you feel are deficient. Shouldn't have to replace the entire unit. You will find Seaward in most boats and they are a reputable manufacturer. IMO, I am not sure about the on demand water heaters. You need power to run them and I don't think that they will heat up while running your engines, which if the anchor out a lot, is really handy.

I will be replacing my pressure relief valve this spring as well. They just get all calcified and start to fail and is not a big issue. Just a thought. Instead of having this valve draining into your bilge, if it is, connect it to a through hull fitting and have it drain out side the boat. My boat came from the Carver factory like that.

GREG

[g36]

I changed mine this past year on my 405. 11gallon square with heat exchanger. Went back with same type Seward model. I agree water seems good and hot from the Seward heaters however I don't recall any adjustment for temp of water. I believe it's a fixed thermostat. you'll have to move your water tank under the bed if you decide to replace the whole water heater.

[Viper]

The thermostat is located behind the front box that sits between the lines and where your wiring goes into. No adjustment on the Seaward (Whale) thermostat, most don't, it's just a non-adjustable thermal open/close switch. There will also be a High Temp Limit switch that will open in case the t-stat fails to shut off, these however are usually reset-able. Here's are some pics: https://www.suremarineservice.com/Galle ... ter-Parts/
Here is a manual: https://www.whalepumps.com/marine/siteF ... Manual.pdf

The pressure relief valve is a safety devise and your last defense if both the above fail or there is sudden high pressure in the system for a reason other than a runaway heating element, so I wouldn't mess with it. If it's leaking, replace it. If that's all that's leaking, I wouldn't bother replacing the whole tank unless there is evidence it's leaking elsewhere as well or you see a sign of a lot of rust around the base of the heater. When replacing the relief valve, make sure that you either use a Sealand replacement or one with the exact spec to maintain safety. Simply grabbing one off the shelf with the same size thread but completely different spec at your local hardware store is dangerous should something go wrong. A good surveyor will catch this. In hopes of it lasting longer, it's a good idea to open and close it periodically. I do it during winterizing to help drain the tank faster, then again at spring commissioning to ensure it made it through the winter.

Dumping the discharge line overboard is great but not advisable in some applications unless you move the heater higher as they're usually mounted pretty close to the water line. The thru-hull would be at the water line in a lot of cases and even if you were comfortable with that, you'd have to make sure it was a downhill run all the way or you'd have standing water in the line. It certainly wouldn't be an option in my application. I have seen drains and reliefs hooked up to shower sumps though.

[Serendipity]

So guys I have been working on the boat during this slow down period and I hope this email finds everyone healthy.

I got the pressure relief valve out of the Seaward hot water heater. For $35 I am going to replace it instead of soaking it and cleaning it. I am also replacing some of the hoses in the area as well.

So I am replacing one hose that has a strainer on it as shown in the pictures. Apparently it has been straining for some time. Date stamp on the side says 5-97. What is this strainer called? It is between the hot water heater and the pump.
So wouldn't you replace this strainer as well?

Thanks in advance,

[tomschauer]

That strainer should be between your water tank and your water pump to protect the pump from debris. If its not clogged and doesn't leak no reason to replace it, its just a stainless steel screen,

[Viper]

Tom's correct, it's usually between the fresh water tank and the pump. Maybe the previous owner wanted to prevent debris from entering the hot water heater but the one before the pump should be enough to catch anything coming from the tank and there should be a screen in your dockside water fitting. If someone wanted to add another strainer, it would be smarter to put it on the outlet line of the hot water heater to minimized sediment and scale from the heater going through the system.