My Seaward S-600 hot water heater is popping the pressure relief valve. Some prior posts suggest changing the thermostat and pressure relief valve. I have the parts and am now ready to install. It looks like the water heater will need to be removed to install them. Is this correct? I'd appreciate suggested detail instructions from anyone who has changed water heater parts. Do I need to remove it? What about the water lines? Any tricks or things to keep in mind?
Not sure about the MK2, on the MK1 they both can be changed in place. Turn the water pump off, turn off the water heater electrical circuit, open the drain, disconnect the wires and unscrew. There are wrenches/sockets availabe at Home Depot/Ace if you cant get a standard wrench/socket on it. Disconnect the pressure relief drain hose if install and unscrew.
When one changes out multiple things you don't know the underlying culprit. If the water temp is ok why the thermostat? Most likely its just a bad valve. Maybe its not important to isolate the root cause but not knowing would make me crazy :nail
I changed the pressure relief valve on my MKll with the tank in place. Have not changed the thermostat in place. If it were me I'd just change the relief valve and see. IMHO the less plumbing work the better. FWIW I think my relief valve failed due to the PO opening the valve when he winterized. Two seasons ago had to replace my water heater. It was a PITA. Got the old tank out with quite a bit of effort. Could not get the replacement in with the batteries in place. So had to remove the batteries and the battery tray. PITA
Randy : I'd try changing the pressure relief valve.
FWIW-I had the pressure relief valve go bad on my furnace this year. It just unscrews. As others have said, I would replace just the valve and leave the thermostat alone.
From earlier posts about this issue:
If your PRV is popping, then your water could be too hot from electric heating. There is NO need to keep the electric working all the time; heat the water, turn the power off; it only takes about 15-20 minutes to heat the water. PRVs have been known to fail when "exercised," which is why there is no reason to do so; crud gets in and keeps it open. If you have crud, it means your heater could be failing; 15 years is usually at the end of its useful service life.
Thanks everyone for your replies and suggestions. This weekend I will try changing just the thermostat. I think it will work in there without removing the entire water heater, and it sounds like a good idea to isolate the problem. To change the thermostat you remove a cover and then some sort of secondary cover which I can't figure out how to remove without taking the whole *!***! water heater out. Hopefully changing the PRV will solve the problem and there will be no need to change the thermostat. Thanks again to everyone!
Could I be the only one who doesn't understand your post?
Are you changing the thermostat (which we recommended as unnecessary) or the PRV?
I am changing the PRV. The prior post was a typo.
Randy : The PRV change out should take care of the engine heated water.
I found that if a PRV is ever manually opened (even to check it) that crud/sediment tends to get caught in the valve gasket and it will always tend to seep a bit.
However, if your shore power is overheating the water and causing the PRV to open - I wrote a Mainsheet tech note article a couple of years ago on changing that AC thermostat out. Not that difficult !!
A few thoughts
Quote from: Ron Hill on March 03, 2016, 02:54:59 PM
However, if your shore power is overheating the water and causing the PRV to open - I wrote a Mainsheet tech note article a couple of years ago on changing that AC thermostat out.
Not that difficult !!
And not at all necessary. Read my earlier post. Just don't keep the power ON all the time. :cry4`
There: just saved you some time and $$. :clap :clap :clap
Betcha have better things to do on your boat. :D :D :D
Good luck.
I will try changing the PRV this weekend and will let you know how it goes. I look forward to getting this one behind me and moving on to the next project.
Ron
Thanks for letting me know there's a Mainsheet article on changing the AC thermostat. I am hoping it's not necessary.
Quote
And not at all necessary. Read my earlier post. Just don't keep the power ON all the time. :cry4`
There: just saved you some time and $$. :clap :clap :clap
Betcha have better things to do on your boat. :D :D :D
I disagree with Stu. The thermostat is an important safety item and if it is not functioning MUST be replaced. It is not acceptable/responsible safe practice to operate a water heater with a malfunctioning thermostat and simply plan on remembering to turn of the breaker after 15 minutes. If one forgets there is risk of scalding, failure of plumbing components due to excessive heat, and in the extreme case a fire should the water boil and get released thru the PRV, leaving the heating element energized in a dry environment. AND, if the PRV was stuck (not applicable in this case where it is already leaking, but could be true otherwise) the whole thing could explode. That said I concur that it is not the most likely cause of your problem, so is probably a moot point to you.
Water heater 15yrs old?
What's the expected life? When do you sign the do not resuscitate form?
I don't know -- but knock on wood, mine appears to be original, and is still working fine--AND, I leave it on 24/7. :shock: :abd:
Quote from: lazybone on March 04, 2016, 02:11:05 PM
Water heater 15yrs old?
What's the expected life? When do you sign the do not resuscitate form?
Anywhere from 10-12 years. Here's my take on it:
http://www.c34.org/mainsheet/html/2014/Water%20heater%20replacement.htm (http://www.c34.org/mainsheet/html/2014/Water%20heater%20replacement.htm)
Quote from: Noah on March 04, 2016, 02:26:21 PM
I don't know -- but knock on wood, mine appears to be original, and is still working fine--AND, I leave it on 24/7. :shock: :abd:
Yup, Noah, good reason to go :shock: :abd: :clap :clap :clap
No reason to unless you're on board all the time and using a lot of water. Otherwise... :donno: :D
Yeah, I should probably rethink my strategy. I do like the convenience of having instant hot water when I am at the boat (every week). A silly part of me is worried that if I shut the dang thing down it may not start up again and thus another project will rear its head. Don't know if 24/7 on, is worse wear and tear than switching it on and off? Thoughts/suggestions?
Quote from: J_Sail on March 04, 2016, 01:26:14 PM
I disagree with Stu. The thermostat is an important safety item and if it is not functioning MUST be replaced. It is not acceptable/responsible safe practice to operate a water heater with a malfunctioning thermostat and simply plan on remembering to turn of the breaker after 15 minutes.
I agree with you, but that wasn't my point. If the thermostat is indeed malfunctioning, it should be replaced. However, we have rarely heard reports of malfunctioning thermostats, but HAVE discussed faulty PRVs hundreds of times, on this and other boating forums. The reasons have already been discussed in this thread.
So, the logic tree is:
--- faulty PRV from opening it and/or having gunk in it that causes it to leak or spout off that is NOT because of the thermostat
--- replace the PRV
--- check that things are working; rarely is it the thermostat
--- if the new PRV spouts, then check the thermostat
But even with a properly functioning thermostat, it makes no sense to leave the water heater ON all the time.
Quote from: Noah on March 04, 2016, 10:01:34 PM
Yeah, I should probably rethink my strategy. I do like the convenience of having instant hot water when I am at the boat (every week). A silly part of me is worried that if I shut the dang thing down it may not start up again and thus another project will rear its head. Don't know if 24/7 on, is worse wear and tear than switching it on and off? Thoughts/suggestions?
Noah, not so much wear and tear but why waste the energy to keep the water hot when you're not there? It's a resistance heater, so turning it ON all the time for fear it won't start again is like saying you keep your engine running??? :D I know you didn't mean that, but... :D
It only takes 15-20 minutes to heat the water. I know, 'cuz I do it all the time. And I turn it off when the water is hot, even when I'm there.
I'm also the guy who turns his house water heater waaay down when I go on vacation. It's gas, so I don't turn it all the way off 'cuz relighting it is a PITA. But I don't waste the energy to keep the water hot when I'm not going to be using it.
It also gets to the operating choices we all make of keeping the boat plugged or not all the time. I just don't do it when I'm not there. Ron Hill and others have commented on this repeatedly.
Your boat, your choice. :D
Guys and Noah : If you ever saw the boats that were damaged at my marina (in the early1990s) you would never say plugged in again!!
It seems that a power line leading into the marina was struck by lightening. All of the wiring on the docks was suddenly energized with 9000 ++ volts instantly!! I wasn't plugged in - thank goodness!
As for manually turning the water heater On and Off manually as Stu mentioned - I did that for a few months and it worked. I would set our coffee pot timer which would buzz so I'd turn off the hot water breaker.
After awhile it did get to me that I had something on my boat that didn't work!!, so my inner-self made me fix it!! It wasn't that costly or that difficult and kind of interesting to do!
When at anchor hiding from a storm/bad weather - my First Mate would accuse me of intentionally breaking something, just so I had something to do by fixing it!! 8)
A few thoughts
Quote from: Stu Jackson on March 04, 2016, 08:05:31 PM
Quote from: lazybone on March 04, 2016, 02:11:05 PM
Water heater 15yrs old?
What's the expected life? When do you sign the do not resuscitate form?
Anywhere from 10-12 years. Here's my take on it:
Replaced mine @ 23 years due to pinhole corrosion leak at tank/house water inlet weldment; @ 15 years I had a split @ other outlet fixed due to freeze/expansion (don't ask.) Always left turned off when not @ slip, typically on whenever aboard.
Nevah a problem w/ PRV, or element or thermostat - so I could have had the second leak fixed, but with the condition of the coil unknown :donno: and being just a little more than what the welder would charged me, I bit the bullet for a new Seaward.
So like my 1984 Facet fuel pump you'd think they could build in a little better quality so they'd last a bit longer!??!! :rolling
(Don't even leave the on if the tank is empty - the element will quickly fry.)
kk
Thanks for the feedback. So, today I TURNED OFF my water heater! It's on you Stu, if next weekend, after 15 mins., I don't have hot water. :? Ron, fortunately San Diego is not lightening prone and I have confidence in my yacht club's electrical system, my Smart plug, updated boat systems/wiring (and my insurance co.), that I have no qualms about keeping plugged in to shore power. Time will tell.
Quote from: Noah on March 05, 2016, 06:25:36 PM
Thanks for the feedback. So, today I TURNED OFF my water heater! It's on you Stu, if next weekend, after 15 mins., I don't have hot water. :D
OMG, I'm in for it now. Pleeeze, wait 20 minutes! :rolling :rolling :rolling
QuoteSo, today I TURNED OFF my water heater! It's on you Stu, if next weekend, after 15 mins., I don't have hot water.
Worried about instant hot water? Need to concentrate on the important things. Like having cold beer on board. :lol:
Jim
A marina just up the road from mine recently lost 23 boats, two lives, a covered boat shed and docks due to fire. Investigation isn't complete yet, but the guess is a fisherman left a heater on in his engine compartment because it wasn't winterized. That is the third fire in 10 years probably caused by staying plugged in. The boats and structures can be replaced, the lives can't.
Hey guys, here's an update. I changed the PRV (not the thermostat) and the problem with it popping open with using the engine to heat water is gone. I'll need to wait a month or so until I spend a few days using shore power to see if the thermostat needs changing.
Guys & Randy : It has been my experience that when a PRV on a water heater is opened (from pressure or manual opening) that sediment on the gasket tends to keep the gasket from ever completely seating again !! Especially with the low pressure in a boat/RV water system.
My thoughts
Quote from: J_Sail on March 04, 2016, 01:26:14 PM
Quote
And not at all necessary. Read my earlier post. Just don't keep the power ON all the time. :cry4`
There: just saved you some time and $$. :clap :clap :clap
Betcha have better things to do on your boat. :D :D :D
I disagree with Stu. The thermostat is an important safety item and if it is not functioning MUST be replaced. It is not acceptable/responsible safe practice to operate a water heater with a malfunctioning thermostat and simply plan on remembering to turn of the breaker after 15 minutes. If one forgets there is risk of scalding, failure of plumbing components due to excessive heat, and in the extreme case a fire should the water boil and get released thru the PRV, leaving the heating element energized in a dry environment. AND, if the PRV was stuck (not applicable in this case where it is already leaking, but could be true otherwise) the whole thing could explode. That said I concur that it is not the most likely cause of your problem, so is probably a moot point to you.
Hi,
I don't think STu said not to change the thermostat, but change one item at the time. First the PRV and see if it work ok. If not then the thermostat.
This is what I understood and what I would also do, go with one change at a time. :D
If you need to replace the unit: I just changed out my hot water heater, (1997, Mark 2) under the guidance of Jack Hutteball, who recently did his. Last year my 11 year old water heater started leaking and I could not find any apparent source, no leaks on fittings. A new S 600 with the back heat exchanger tubes was $250. at Sure Marine in Seattle. Removed two batteries closest to the hot water heater. Also had to move the isolator to make more room. easy to disconnect wiring and in and out water hoses from the front of the unit. hard to reach the clamps in the back to the heat exchanger hoses, but tilted it first to one side and then to the others and got them off. Jack plugged the hoses as they came out so had very little coolant escape. Jack had suggested we put a pigtail on the back of each of the heat exchanger hoses so that connection can be super tight. (I put 2 clamps on each hose at the back of the heat exchanger). We then make the connection using copper couplings to join the pigtail to the lines, from inside the sink and drawer cabinet. (the drawer cabinet slides out as far as where the stove door allows to give you access to work on the outermost heat exchanger line.) Took about 7 -10 minutes running the water pressure bleeding out the air, opening and closing the faucet. Electric side of the heater is working great. Will still need to figure out how to bleed the heat exchanger lines. But, if you don't have to switch out the unit you are way ahead!
Randy's right, and although Jack's is a Mark II, similar situations occur. Here's my story:
http://www.c34.org/mainsheet/html/2014/Water%20heater%20replacement.htm
JSail is also right, and that's what I said, didn't I? :D
Noah: How'd it go with leaving it off while you're not there?
No issues so far with leaving it switched off. :thumb: thanks for asking. Been too busy chasing down my " jumpy" fuel gage issue, and some new deck rain leaks last week (thank you El Nino). No "need" for hot water! Pulled aft starboard bulkhead (again) and my cockpit instrument panel (again) last weekend, chasing possible bad ground or bad tank sender. Of course, I left all open pending finishing this weekend--now lots of rain. Always something. Spent my lunch hour today covering all with plastic. Never enough quality time available, in a single stretch, to devote to the boat. My "real job" has got to go....soon!