Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-13-2018, 10:06 AM   #21
Guru
 
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48 (sold)
Join Date: Apr 2008
Posts: 10,186
Quote:
Originally Posted by O C Diver View Post
OP would probably have better luck calling Nordic Tug. Ted
YUP! Too many "Ts"
sunchaser is offline   Reply With Quote
Old 03-13-2018, 07:02 PM   #22
Grand Vizier
 
Delfin's Avatar
 
Join Date: Jan 2010
Posts: 3,816
OC is likely correct. You must have an expansion tank in the hot water side of your system. If you don't, install one. If you do, it has lost pressure.
__________________
"Dad always thought laughter was the best medicine, which I guess is why several of us died of tuberculosis." - Jack Handey
Delfin is offline   Reply With Quote
Old 10-31-2018, 05:46 PM   #23
Member
 
gknoepfler's Avatar
 
City: New Orleans
Join Date: Mar 2017
Posts: 18
My overflow is also dripping into the bilge without the water heater being on. It's cold water dripping. Based upon this thread, I would assume it is probably the relief valve?
gknoepfler is offline   Reply With Quote
Old 10-31-2018, 06:21 PM   #24
Guru
 
OldDan1943's Avatar
 
City: Aventura FL
Vessel Name: Kinja
Vessel Model: American Tug 34 #116 2008
Join Date: Oct 2017
Posts: 10,595
It is correctly called a Temperature, pressure relief valve. If it leaks, replace it. Chances are, the problem will go away. This is where I would start.

When I had my home hot water heater replaced, he installed a small expansion tank on top of the hot water heater. It is a new "code" requirement. Seems a bit redundant to the existing tank relief valve.
__________________
Two days out the hospital after a week in the hospital because of a significant heart attack.
OldDan1943 is offline   Reply With Quote
Old 11-01-2018, 05:10 AM   #25
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in the Great Lakes
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 12,835
Quote:
Originally Posted by OldDan1943 View Post
When I had my home hot water heater replaced, he installed a small expansion tank on top of the hot water heater. It is a new "code" requirement. Seems a bit redundant to the existing tank relief valve.
Many municipalities are going to a check valve between the city water supply and your home. Theoretically it isolates any contaminants in your system from migrating into the city's system. Without an expansion tank, when the water is heated and it expands, it has no place to go (except out the relief valve). The expansion tank gives the water a place to go and the relief valve only operates when the thermostat fails.

Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 11-01-2018, 09:11 AM   #26
Guru
 
City: gulf coast
Join Date: Jun 2014
Posts: 3,440
If you use engine heat for the water tank you need a high temp relief valve.
bayview is offline   Reply With Quote
Old 11-01-2018, 09:51 AM   #27
Senior Member
 
Westiculo's Avatar
 
City: Boston
Vessel Name: Rose Mary
Vessel Model: 42 Grand Banks Motoryacht - 1985
Join Date: Feb 2017
Posts: 271
I tested my relief valve a few weeks ago by pushing the lever to see if water would come out - big mistake. Damn thing wouldn't seal after that, had to get it off of a 30-year-old water heater. Finally got it with a huge vice grips. If you can get it off, it's as simple as just screwing a new one on - problem solved.
Attached Thumbnails
relief.JPG  
Westiculo is offline   Reply With Quote
Old 11-01-2018, 11:03 AM   #28
Guru
 
Maerin's Avatar
 
City: East Coast
Vessel Name: M/V Maerin (Sold)
Vessel Model: Solo 4303
Join Date: Jun 2013
Posts: 886
Quote:
Originally Posted by O C Diver View Post
Many municipalities are going to a check valve between the city water supply and your home. Theoretically it isolates any contaminants in your system from migrating into the city's system. Without an expansion tank, when the water is heated and it expands, it has no place to go (except out the relief valve). The expansion tank gives the water a place to go and the relief valve only operates when the thermostat fails.

Ted

To expand on Ted's accurate reply.. Most codes now require a dual check valve, they allow NO backflow. Commercial applications may require a "reduced pressure principle" valve that has a chamber that opens to the atmosphere when the downstream pressure exceeds the inlet. By code, those valves require periodic testing by certified techs with certified testing gear.



The backflow device prevents any thermal expansion from backing out the supply line. The increased pressure can open the T&P valve, and absent that, can create enough pressure in the water heater to crush a flue passage, distend the bottom of the tank to the extent it becomes a "weeble", or in rare cases where an ignorant homeowner has plugged or modified the T&P valve, a runaway heater can flash its contents off into steam and quite literally become a bomb. Superheated water can flash into steam ~1025 times its volume in the flash of an eye. A T&P valve is nothing to trifle with.



The expansion tank absorbs the volume of expanded water. Worth noting is that the expansion tank is installed on the COLD piping. It's not rated for hot water, I've seen lots of improper installs, sometimes they work, doesn't make it right.



Our marine water heaters can benefit from an expansion tank, but the typical presence of a check valve on the inlet of the water heater complicates installation. Since the inlet check's function is to prevent a volume of heated water from backflowing into the cold supply (different function from the dual check), installing an expansion tank on the cold line is ineffective. The reaction is to install it on the hot line, which may work, but can often create more problems. With the potential for very hot water due to engine heating, the tank is subjected to conditions beyond its design parameters with resultant premature failure.
The simplest solution is to modify the check valve by creating a small bypass by drilling a very small hole (<1/16") in the flap, or filing a notch in the seat. This preserves the function of preventing the hot flow into the cold lines, while providing a path for the thermal expansion to find its way to the expansion tank or accumulator if the system is so fitted. If an accumulator is already present and large enough, modifying the check valve may provide enough reservoir to absorb the expansion without the need to add a supplemental additional expansion tank. Plus, the expansion tank can be installed anywhere in the cold piping where it's convenient.



If your T&P valve isn't leaking and you "test it", it will be leaking soon! If it ain't broke.... If a T&P valve is leaking, REPLACE IT with a new one having the same rating as the one removed. They are rated at a temperature, and pressure, with a btuh capacity. A replacement should be of equal rating, and not exceed the working pressure rating of the pressure vessel that it's protecting. The btuh rating must be equal or greater than the btu heating capacity of the water heater. It should NEVER be substituted with a pressure relief only valve. Because...The boiling point of water at 150 psi (typical pressure rating of a water heater) is 358F. If a runaway heater has no thermostatic limit, it can conceivably get to 150 psi and won't relieve. If for some reason that pressure is relieved, the boiling point suddenly plummets and the water at 350F flashes into steam. The water heater has become a bomb.

Not typically a huge concern in our marine applications, but worth knowing the WHY's when the subject of T&P comes up in discussion.
__________________
Steve Sipe

https://maerin.net
Maerin is offline   Reply With Quote
Old 11-01-2018, 11:11 AM   #29
Guru
 
Maerin's Avatar
 
City: East Coast
Vessel Name: M/V Maerin (Sold)
Vessel Model: Solo 4303
Join Date: Jun 2013
Posts: 886
Quote:
Originally Posted by bayview View Post
If you use engine heat for the water tank you need a high temp relief valve.

No, you need to control the temperature of the water.
__________________
Steve Sipe

https://maerin.net
Maerin is offline   Reply With Quote
Old 11-01-2018, 11:39 AM   #30
Senior Member
 
Westiculo's Avatar
 
City: Boston
Vessel Name: Rose Mary
Vessel Model: 42 Grand Banks Motoryacht - 1985
Join Date: Feb 2017
Posts: 271
Quote:
Originally Posted by Maerin View Post
If your T&P valve isn't leaking and you "test it", it will be leaking soon! If it ain't broke....
I agree; the reason I tested it is because it says right on it 'test annually'
Westiculo is offline   Reply With Quote
Old 11-01-2018, 11:52 AM   #31
Guru
 
City: gulf coast
Join Date: Jun 2014
Posts: 3,440
Quote:
Originally Posted by Maerin View Post
No, you need to control the temperature of the water.
How do you do that?
bayview is offline   Reply With Quote
Old 11-01-2018, 11:55 AM   #32
Grand Vizier
 
Delfin's Avatar
 
Join Date: Jan 2010
Posts: 3,816
Because Marine water systems all rely on an on board pump for pressure (if not connected to shore water), I believe you'll find that check valves are a mandatory component of every pump to avoid bleeding pressure back into the storage tank, and can't/shouldn't be fiddled with. A hot water rated expansion tank on the output side of the water heater, or a cold temp rated tank on the inlet side makes living with pressure/temp relief valves a bit easier.
Delfin is offline   Reply With Quote
Old 11-01-2018, 02:53 PM   #33
Guru
 
Maerin's Avatar
 
City: East Coast
Vessel Name: M/V Maerin (Sold)
Vessel Model: Solo 4303
Join Date: Jun 2013
Posts: 886
Quote:
Originally Posted by Delfin View Post
Because Marine water systems all rely on an on board pump for pressure (if not connected to shore water), I believe you'll find that check valves are a mandatory component of every pump to avoid bleeding pressure back into the storage tank, and can't/shouldn't be fiddled with. A hot water rated expansion tank on the output side of the water heater, or a cold temp rated tank on the inlet side makes living with pressure/temp relief valves a bit easier.

No, the check valve in the pump prevents pressurized water flow back into the storage tank/suction line. Without an inlet check, the pump would constantly cycle. The check on the water heater cold inlet is solely to prevent backflow of heated water into the cold piping. Creating a bleed path WILL NOT defeat its intended purpose, nor will it have any detrimental effect otherwise. I would not suggest doing it if that were the case.
__________________
Steve Sipe

https://maerin.net
Maerin is offline   Reply With Quote
Old 11-01-2018, 03:11 PM   #34
Grand Vizier
 
Delfin's Avatar
 
Join Date: Jan 2010
Posts: 3,816
Quote:
Originally Posted by Maerin View Post
No, the check valve in the pump prevents pressurized water flow back into the storage tank/suction line. Without an inlet check, the pump would constantly cycle. The check on the water heater cold inlet is solely to prevent backflow of heated water into the cold piping. Creating a bleed path WILL NOT defeat its intended purpose, nor will it have any detrimental effect otherwise. I would not suggest doing it if that were the case.
I believe that is exactly what I wrote. Quoth I..."I believe you'll find that check valves are a mandatory component of every pump to avoid bleeding pressure back into the storage tank, and can't/shouldn't be fiddled with."

Your recommendation that you drill holes in a check valve associated with the water heater kind of begs the question of how that accomplishes anything if the check valve in the pump is preventing a backflow of water through the cold water line? Further, I probably missed it, but water heaters don't come with check valves in the first place, although they can certainly be installed. Once installed, any cold water expansion tank might be isolated, which is why a rated hot water expansion tank on the hot water side is the preferred solution. https://www.plumbingsupplynow.com/pl...nt=Catch%20All

To make it a bit more muddy, some folks confusingly refer to the TP relief valve as a check valve. Go figure. https://www.reference.com/home-garde...922c7880e2a195


And for what it's worth, plumbers on hot water check valves....https://www.plbg.com/forum/read.php?1,231398
__________________
"Dad always thought laughter was the best medicine, which I guess is why several of us died of tuberculosis." - Jack Handey
Delfin is offline   Reply With Quote
Old 11-01-2018, 03:11 PM   #35
Guru
 
Maerin's Avatar
 
City: East Coast
Vessel Name: M/V Maerin (Sold)
Vessel Model: Solo 4303
Join Date: Jun 2013
Posts: 886
Quote:
Originally Posted by Westiculo View Post
I agree; the reason I tested it is because it says right on it 'test annually'

Says the manufacturer who's in the business of selling T&P valves. It also has the collateral benefit of reducing their liability exposure.



As a service provider, inspection was our SOP, any evidence of prior leakage would be cause to recommend replacement of the T&P. Active leakage was a "must replace" and any plugged device would be a replace, period. If I saw a plugged relief in the course of a site visit, I would correct it or tag out/lock out, even if I was not paid for the service; then document it & have the homeowner sign off if they declined a repair. As a professional, I could be held liable for not correcting a life safety issue like that or in the instance of a heating appliance that's producing CO. "Testing" a T&P was never on our task list- inspect or replace!
__________________
Steve Sipe

https://maerin.net
Maerin is offline   Reply With Quote
Old 11-01-2018, 03:36 PM   #36
Guru
 
Maerin's Avatar
 
City: East Coast
Vessel Name: M/V Maerin (Sold)
Vessel Model: Solo 4303
Join Date: Jun 2013
Posts: 886
Quote:
Originally Posted by Delfin View Post
I believe that is exactly what I wrote. Quoth I..."I believe you'll find that check valves are a mandatory component of every pump to avoid bleeding pressure back into the storage tank, and can't/shouldn't be fiddled with."

Your recommendation that you drill holes in a check valve associated with the water heater kind of begs the question of how that accomplishes anything if the check valve in the pump is preventing a backflow of water through the cold water line? Further, I probably missed it, but water heaters don't come with check valves in the first place, although they can certainly be installed. Once installed, any cold water expansion tank might be isolated, which is why a rated hot water expansion tank on the hot water side is the preferred solution. https://www.plumbingsupplynow.com/pl...nt=Catch%20All

To make it a bit more muddy, some folks confusingly refer to the TP relief valve as a check valve. Go figure. https://www.reference.com/home-garde...922c7880e2a195


And for what it's worth, plumbers on hot water check valves....https://www.plbg.com/forum/read.php?1,231398

Evidently, I didn't make my point clearly. I did refer to the check on the water heater, its sole purpose is to prevent hot water from backing into the cold supply. It's independent of the pump and has no function in preventing the pressurized water from backing into the suction line of the pump or the storage tank. That is the function of the check on the pump, and without it the pump will cycle. Two different check valves, two entirely different functions. What did I miss?


The link you provided is for an Extrol EX-30. It's a thermal expansion tank designed for use in hydronic systems, not potable water. Entirely different tank than the thermal expansion tanks for use on pressure water systems (ST series). The Extrol 30 will tolerate 190F water in use on a hydronic system, but pressures there are <15psi. And it's a closed system, so the water in that system is inert for all intents and purposes. The EX-30 wouldn't last on a water heater application; that's simply not what it's designed for.

The preferred solution for a water heater application is a thermal expansion (ST) tank on the cold side of the supply piping. Providing a bleed path through the water heater inlet check allows a de minimus flow of thermal expansion back through the water heater inlet check and thus to the piping that the thermal expansion tank is connected to. Not enough to heat the line, but enough to allow installation of the ST tank anywhere on the cold side where it is preferred and will last the longest. It won't have any bearing on the pump check valve.

Regarding the link to whatever idiot wrote the drivel on check valves on water heaters being a safety device, it IS the internet. That makes it true, not?? Similarly, the link about check valves written by the apprentice is a common question. A residential heater may have heat trap valves from the manufacturer, but the dip tube configuration is typically enough to keep the contents from backing into the cold supply line. Because marine heaters are more often than not piped with side inlet/outlet, there's little to prevent flow of hot water or thermal convection into the cold supply piping, so a check valve is frequently installed for that purpose. I doesn't have to seal perfectly to achieve that purpose.
__________________
Steve Sipe

https://maerin.net
Maerin is offline   Reply With Quote
Old 11-01-2018, 04:02 PM   #37
Grand Vizier
 
Delfin's Avatar
 
Join Date: Jan 2010
Posts: 3,816
Quote:
Originally Posted by Maerin View Post
Evidently, I didn't make my point clearly. I did refer to the check on the water heater, its sole purpose is to prevent hot water from backing into the cold supply. It's independent of the pump and has no function in preventing the pressurized water from backing into the suction line of the pump or the storage tank. That is the function of the check on the pump, and without it the pump will cycle. Two different check valves, two entirely different functions. What did I miss?
I gather you must be suggesting that a check valve be installed to prevent thermal transfer of heat from the hot water side to the cold water side, since an actual flow of water from hot to cold is prevented by the check valves in the water supply pump. One would think a heat trap might be more efficient, but ok. Once you drill holes in the check valve it seems like you are pretty much defeating the purpose, but again, ok.


Quote:
Originally Posted by Maerin View Post
The link you provided is for an Extrol EX-30. It's a thermal expansion tank designed for use in hydronic systems, not potable water. Entirely different tank than the thermal expansion tanks for use on pressure water systems (ST series). The Extrol 30 will tolerate 190F water in use on a hydronic system, but pressures there are <15psi. And it's a closed system, so the water in that system is inert for all intents and purposes. The EX-30 wouldn't last on a water heater application; that's not what it's designed for.
Quite right. I had that model on the brain since I just installed one in my hydronic system. That said, most all potable water expansion tanks I've seen are all rated for 150 psi and 200 degrees anyway and are protected by the TP relief valve, so if you do feel compelled to install a check valve, rather than drilling holes in it, installing the tank on the hot water side would seem to make sense.

Quote:
Originally Posted by Maerin View Post
The preferred solution for a water heater application is a thermal expansion ST tank on the cold side of the supply piping.
True. Until you install a likely unneeded check valve (on a closed marine system) that would prevent it from working.



Quote:
Originally Posted by Maerin View Post
Regarding the link to whatever idiot wrote the drivel on check valves on water heaters being a safety device, it IS the internet. That makes it true, not??
True enough. There is sufficient bad advice on the Internet to go around.
__________________
"Dad always thought laughter was the best medicine, which I guess is why several of us died of tuberculosis." - Jack Handey
Delfin is offline   Reply With Quote
Old 11-01-2018, 04:52 PM   #38
Guru
 
Maerin's Avatar
 
City: East Coast
Vessel Name: M/V Maerin (Sold)
Vessel Model: Solo 4303
Join Date: Jun 2013
Posts: 886
Quote:
Originally Posted by bayview View Post
How do you do that?

Started new thread:
http://www.trawlerforum.com/forums/s...mps-41387.html
__________________
Steve Sipe

https://maerin.net
Maerin is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 08:41 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012