HOT WATER TANK PRV Blows off when weather is cold?


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Old 01-30-21, 07:16 PM
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HOT WATER TANK PRV Blows off when weather is cold?

I live in New York, I have a 30 Gal John Wood Water heater tank , oil fired older riello burner, bought at home depot about 3 yrs ago, after 1 yr, every time its cold the PRV blows off.
This weekend is the first cold spell into the teens this winter and its happenning again. Local plumbers by phone told me last winter/spring, i shouldnt have been running the tank at 140 degrees, finally in march I lowered it to around 125 but the weather has not been cold since march until now.
I do have an expansion tank, did that last winter it solved nothing, i have changed the valve a few times , it solved nothing.
1- Does anybody understand why this only happens in 15 degree weather and what I can do about it?
2- Also is it so "wrong" to run it AT 140 degrees ? I live in this house all my life, hot showers have always been a problem in winter. 120 will not get you a hot shower, withe 40 or 50 ft runs to get to the various bathrooms.
3- Of course licensed plumbers want to tell me the John Wood tank from home depot "is not the same as the ones they sell and install " ( for double the price of course) any truth to this?

It never happens march thru moderate winter temperatures....ONLY when we get deep freeze "teens" here like this weekend. I put it down to 100 degrees tonight, because it blew 2 times today. One local plumbing hobbyist said to change the aquastat, but that still wouldnt explain why it happens only in cold weather. If the aquastat was wrong it should blow all year around.

appreciate any ideas. tnx


 
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Old 01-31-21, 08:14 AM
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Nothing wrong with the water heater set to 140 degrees except the big problem of accidental scalding when using the hot water.

You should check the internal (preset) pressure of the expansion tank, you can use a tire gauge. Shut off the cold feed to the water heater and open an upstairs hot faucet first and then measure.. Then close the faucet, open the cold feed, and measure the pressure again. The two readings should be about the same, probably somewhere around 40 psi.

Use a tire pump if needed to reset the expansion tank pressure with the hot faucet open to match the system pressure with all upstairs faucets closed, if needed,.

If a lot of water comes out the Schrader valve (air inlet possibly covered with a plastic screw on cap) when you are trying to adjust the pressure in the expansion tank then the expansion tank needs to be replaced.

Every new tankful of water will expand when heated. On a cold day the incoming water may be at a lower temperature so it expands more as it gets to the desired temperature (140 degrees?).

Water does not compress (compress measurably). If there are no air pockets or air cushions in the system then the expanding heating water will not stop expanding and instead something else has to give.
 

Last edited by AllanJ; 01-31-21 at 09:16 AM.
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Old 01-31-21, 08:49 AM
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Welcome to the forums.

You "know" where the water temperature is set to.
Have you actually measured the water temperature ?

30 gallon is pretty small for a water heater but I would think with an oil burner it should recover quickly.
 
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Old 01-31-21, 10:43 AM
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hi pete and allan thank you,
1- pete yes i know how to set it on the aquastat...but I was trying to figure out how to "measure the water temperature". locally someone said to use a regular meat thermometer, i tried in a bucket of water i let out of the relief valce, no temperature...i was searching on the web for submersible thermometer, no luck... any easy to find solutions to check temp on the water?
2- Allan I did the suggested check on the expansion tank when I got it, and it matched my outside hose faucet pressure out of the box from home depot, (which one local plumber old timer concurred would be the case YET another said i needed to buy "his expansion tank (triple the price). I can try checking it again but ditto what i wrote earlier a few days after buying the expansion tank the relief valve blew, so i figured that likely was not the problem.
3- Aquastat is prob 25 yrs old honeywell..., I still have the same concern, if was the aquastate wouldnt it blow in the summer too? it only happens when its temps in the teens locally.

4- I thought i saw something here last year but couldnt find it again about "street water" being colder in the winter, and expanding, and a certain sort of regulator to the Hot water heater to make it work better? I dont know...but that sounded more like a water company thing than a homeowner thing?

Im thinking a wet thermometer would be a great starting point, to eliminate the aquastat...but wouldnt this happen in july if it was the aquastat?

Based on my recent experience setting humidity in another room for a piano, and the flakiness of hygrometers im gonna guess that aquastats and thermometers can have the same issue, though im thinking temp is eaiser to measure than humidity.

tnx all,




 

Last edited by mikecat; 01-31-21 at 11:28 AM.
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Old 01-31-21, 12:24 PM
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A couple of questions. What do you have for an expansion tank size wise and is it the right tank. It is not the same tank as for your boiler.
What is your water pressure in the house. You should have no trouble running that tank at 140 and the tank I don't believe knows if it's summer or winter.

When your relief valve blows if you open a faucet does it stop. You may be running that tank as a closed loop with no place for the hot water to migrate like a boiler and it's not made for that. Do you have a pressure reducing valve or a backflo preventer on there. Both of these make the tank work as a closed loop.

You can use a candy thermometer or almost anything to measure water temp. On your tank you have a T&P relief valve and not just a pressure relief valve like a boiler. Look at your tag on the relief valve for the limits. It may be 150 psi and 210 deg. It would be good to know which one is setting it off.

Pics of your tank and expansion tank and piping would be helpful if possible.

Hope this helps a little.
 
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Old 01-31-21, 01:23 PM
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1- expansion tank 4.5 gallon, factory preset@ 40psi, the label says maximum 150psi, it also says 20 degrees not sure what that means

2- Relief valve label indicates 210 degree F and 150 psi.

3- I found i have a frothing thermometer here , i compared furthest "sink" cup of water...to local bucket near hot water heater, both were 100 degrees which matches the aquastat setting i put it on since yesterday.

4- I can find my gauge but when i bought the tank, i checked the outside garden faucet pressure on house and I remember it matching the tank measure by a gauge (not reading the label) im thinking 60psi sounds familiar....

i've been too afraid of flooding to try turning on a faucet when the relief valve blows. Im not aware of pressure reduciing valve, or backflo preventer doesnt sound familiar, but i can take some pics a little later.


 
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Old 01-31-21, 01:57 PM
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Pics of my hot water heater





 
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Old 01-31-21, 05:11 PM
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PS to above, I dont know what is a T&P relieft vale, i put a pic of the tank label, only valve i see is the preassure relief valve that is blowing off in cold weather.
 
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Old 02-01-21, 09:18 PM
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Still unresolved here welcome any ideas anybody may have, outside temp is now 33 degrees, hot water tank is set at 110 degrees, and the relief valve isnt blowing, If the weather gets colder again i'll have to lower it i think
 
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Old 02-02-21, 07:12 AM
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Could your relief valve be getting old and blowing at a lower temperature (exact number unknown at this moment) than what it was rated for?

How long was it between the time the last person (or dishwasher cycle or washing machine cycle) used hot water and the time the relief valve blew?

If you ran a hot faucet for ten seconds after one third of that time interval and after two thirds of that time interval does that prevent the relief valve from blowing?

Turning on a faucet when the relief valve blows will not cause a flood. But that will also not prove anything or cure anything because by the time you walked halfway to the kitchen or bathroom to reach the faucet the overpressure due to expansion will have been relieved and the relief valve would have closed again.

 
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Old 02-02-21, 07:51 AM
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Aquastat is prob 25 yrs old honeywell
.


Where is the Honeywell Aquastat? I don't think it's pictured.
 
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Old 02-02-21, 02:05 PM
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hi Allan and Zoesdad
1-Zoe, correction its not a honeywell i was mistaken its the brand in the picture above. is probably circa 1990 from my fathers last hot water heater. The aquastat and riello burner were transfered to this one. I compared water temp over the weekend it matches the aquastat.

2- Allan, I've changed the relief valve several times on suggestions from local people, but it didnt prevent it from blowing when the weather is cold. This relief valve was probably changed last spring im thinking. Your point is if i try to turn on a HOT WATER faucet when the valve goes off, that MIGHT make it stop blowing off? Thats sounds like a good test to try. Right now im taking luke warm showers w aquastat @110 degree, outside temp is 37 degees, so technically I COULD try to crank up the aquastat...but it seems to only blow when the weather is cold.
One old timer plumber last year suggested by phone that the cold water, in the ""teen temp" weather, entering the water heater could cause combustion if the heater is set to 140, etc.........doesnt make sense to me, and thats why im here. So far everybody agrees it should be able to handle 140,..

Tnx
 
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Old 02-02-21, 02:34 PM
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M,
Have you checked your expansion tank. If you tap the top with a screwdriver it should sould solid and tapping the bottom should sould tinny because that's where the air bladder is. If the whole tank sounds solid then your bladder is gone and the tank needs replacing or at least recharging if possible.

The colder it is outside the colder the fresh water will be that enters the tank and the longer the burner may have to run to reach temp. If your expansion tank is bad or needs a charge the longer the burner runs the expansion tank may have a problem with the pressure.

There's only a couple of things that set off the relief valve, temp or pressure. If you're taking luke warm showers I'm guessing it's not the temp which is set to go off at 210. My guess would be pressure. That is why I suggested in a former post when the relief valve starts to leak open up a faucet to see if that relieves the pressure and the relief valve should stop leaking immediately which will tell you it's pressure.

Since the relief valve is set for 150, unless your house has tremendous pressure which is doubtful it must be pressure caused by the heated water. With a relief valve set at 210 your 140 should be no problem.

Just a thought.
 
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Old 02-02-21, 08:37 PM
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hi spott, i see what you're saying. as you und im doing the luke warm showers because its down at 110 now on the aquastat. Prior to the renewed crisis this weekend I had it had 125. taking fairly warm showers...not as hot as i'd like.
1- the expansion tank is what you said it should be solid on top tinny on bottom, so i guess thats fine.

2- Im not sure i can force the relief valve to blow as its warmer weather now and it only blows when its cold outside, but i'll turn up the aquastat during the day...when im awake to catch a possible flood,

QUESTION: If I turn on the sink and the relief valve goes closed what does that tells us and what do i do then?

General problem is i can't make this happen when the weather is warm so the diagnostic concepts i gotta try or keep in mind next cold spell. im sure we'll have more cold weather ahead in feb. I'll try it tonight but its 38 degress outside i suspect the valve won't blow. PS whoever asked about flood, or what i meant was i have a large 5 galloon bucket for the relief valve, but it blows off much more than that. Prior to the discovery i really didnt know what the floods were in the basement (when the weather was cold).

Tnx
 
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Old 02-03-21, 01:14 PM
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I called my local water district, the supervisor there said that normal street pressure around here is 60 PSI, on a cold cold quiet night it could go up to 75 but doubtful. He himself had bought an expansion tank and did not set the pressure until someone told him to , also he said he was told the home depot expansion tanks are the wrong ones for this.
1- Anybody familiar with the everbuilt home depot expansion tank i have in my pics...is it possible its not right for hot water heater?
2 What is the proper way to set the pressure on my expansion tank, do i simply shut off the incoming water, then check it with a gauge? do i gotta remove it first? since it says factory preset to 40 and my street is 60. it seems like its worth trying this, and if the home depot tank is wrong, i'd be better off getting maybe another one like Amtrol ?
 
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Old 02-03-21, 04:20 PM
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I have never used the Everbuilt tank, I use the Amtrol Thermxtrol but before you rush out to get another tank as long as your has a 3/4 tapping and preset @ 40 psi I believe it should work on your heater. The most important thing though is to precharge the tank to match your incoming water pressure. If you left it at 40 but your incoming pressure is 60 or 70 you already have that pressure pussing on the bladder taking up room in the tank even before you start to heat the water so you have less room for expansion.

I was under the impression you read the instructions and increased the pressure. I just misread the post. You will have to shut off the water and relieve the pressure or remove the tank and pressurize it to at least 60 or 70 psi and that might solve your problem.

By the way HD sells Amtrol thermxtrol tanks also or you can check SUPPLY.COM which is cheaper and ship quickly. If you get a Thermxtrol get the ST - 12 and not the 5. Holds more volume

https://www.supplyhouse.com/Expansion-Tanks-14860000

Hope this helps a little.





 
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Old 02-03-21, 04:47 PM
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tnx Spott, yes i thought i had pressurized the expansion properly but talking to my town water supply guy i remembered i can't check the pressure when its connected that was the mistake i did last year. now you all here had me re-think and reading the label, it says its preset at 40, so probably worth a try.

Googling around today, seems to me, turn off the water supply, let it cool down then uncrew the tank, check the pressure and fill it with a tire pump does that sound right?

 
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Old 02-04-21, 05:46 AM
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Easier: Turn off the cold water supply to the water heater (or to the house), open a hot faucet and let the pressure die down. After that, yes you can check the expansion tank pressure with the tank still attached.

It's more complicated removing the expansion tank because if you are not careful, there is water in the pipes upstairs that will come down and out the opening when you remove the tank.
 
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Old 02-04-21, 12:24 PM
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M,
My suggestion would be to shut the water off to the house and then open up the hot and cold faucets to drain some water but mainly to break the vacume in the lines.

Then open the tank relief valve and drain until water stops. That way you will know when the water is below the expansion tank level then you can remove the tank and empty the water out from the tank and start fresh with a tank just as you bought it. If you get a little leaking water that bothers you just screw a 3/4 threaded plug into the fitting until you are done.

What you can do while the tank is off is to add a 3/4" ball valve between the tank and the fitting for future maintenence using a brass nipple because of domestic water.

Just a thought. Hope this helps a little.
 
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Old 02-06-21, 01:48 PM
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hi all, well i did check it just now, i didnt remove the tank, but i did open the sinks and let some water out of the water tank relief valve.
I put the tire gauge/inflator on the expansion tank, it was reading 55, assuming its accurate i goosed it up to 60 to match street pressure. Actually i goosed it to prob 62.
I didnt remove the tank cuz i didnt have a 3/4 ball valve on hand to close it off, but im pretty darn sure all the
pressure was relieved because nothing came out of the relief valve and nothing dripped out of the tire valve on the expansion tank.

What you thinking? IM thinking that 55 to 60, might not make a different for the relief valve to blow?
Maybe just to be sure i should indeed buy a new expansion tank, have a plug/valve on hand to do the swap and hopefully do this before we get another cold snap?

RECAP top of expan tank= solid, bottom= tinny on tapping. Alleged pressure increased from 55 to 60, would that make a difference in my dilemma, or start fresh w a new tank? ALSO if my town water supply people say on cold quiet nights pressure can increase up to 75 PSI, should i be cheating this higher than their average goal of 60?

tnx


 

Last edited by mikecat; 02-06-21 at 02:06 PM.
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Old 02-07-21, 11:33 AM
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If your tank came precharged at 40 and that is how you installed it you have to ask yourself how why would it read 55 after you thought you depressurized the system. The bladder does not inflate itself.

I realize what another poster said you had to do and that is what you did but my guess is that you still had pressure in the tank because of the 55 psi reading on the gauge instead of the 40 that is was set at. As far as water not coming from the schrader valve, it shouldn't ever come from there unless the bladder is blown.

That schrader valve is connected to an air bladder like a bike tube so no water has access to the inside of that tube unless there is a leak in it.

The 55 psi you were reading was still street pressure because you didn't empty you tank. If you drain as was earlier described and put your 5 gal bucket to catch drips while you tank your tank down or wait until you get a valve or plug and remove the tank and empty it it and check the pressure for proper reading and then charge to whatever you need you might be fine.

If you get another tank you will have to go through the same procedure before you install it. Inflate to whatever your street or house pressure is. Even if your street pressure is 75 as long as you have a pressure reducing valve set at 60, the 75 doesn't matter in your case.

By the way did your last procedure stop the leaking.
 
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Old 02-07-21, 01:11 PM
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hi spott, sorry if im a little confused, i was kinda chicken to remove the tanki cuz. I havent cranked up the hot water temp yet, and the weather is moderate at almost 40 degress, so will be hard to know if successful even if i buy a new expan tank which i should.

I honestly dont know if last winter i do shoot some air in it when i was evaluating the problem , i just dont rememeber...if i did that could be why its 55 .and yes i did drain the relief valve into a bucket yesterday till it stopped draining yes i did that , i do suspect i relieved all pressure yesterday and it indeed was 55.

Ok and thank youf or what you write about 75, again i think for me best move is get a fresh new expansion tank and start from scratch, buy a 3/4 plug to have on hand in case there's a leak and goose the air in the new tank before installing.

If i put a new expansion tank now and weather never gets cold enough to blow the relief valve and things warm up, thru summer, does that mean the new expansion tank is sitting "EMPTY", or are they working in the background and we never know?

Also my town water clerk asked me if i had a backflow preventor near my main, he said that could possibly cuz whats happenning with me. If i took a picutre of my main, is that something you can identify?

tnx again





 
  #23  
Old 02-07-21, 03:30 PM
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At the risk of being repaticious, although I know this has been your experience with the cold weather, the weather in reality has nothing to do with your problem. They do not make hot water tanks for different parts of the country. There are some people with very small amounts of baseboard that use these tanks as boilers with no problems. You have to reset your mind about this cold weather thing and concentrate on what the real cause of the problem is.

In an earlier post I mentioned a backflo preventor as a reason why these tanks are used. Years ago before BFP and Check Valves and PRV were used these tanks were never used because the water used to be able to migrate through the water system and absorb for lack of a better word, the pressure built up from the heated water.

The backflo prevtor doesn't have to be on the main coming into the house. It can be anywhere on the cold water pipe going to the tank so if you take pics of all your piping from the main coming into the house to the tank I can tell you if you have one.

Be patient, we'll figure it out. It's not rocket science.

Relax and enjoy the super bowl.
 
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Old 02-07-21, 09:26 PM
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Thanks Spott. I have one question when the relief valve blows, typically is it just a few gallons?
Last winter I didnt know what the basement flood was in my finished basement, im sure 5 gallons could make quite a mess, until finally one night i was awake and "heard" the relief valve blow. NOW i have a bucket 5 gal under it with the hose coming out of the valve. The only 2 blows this season i was home and heard the alarm.

On a 30 gallon tank, the relief valve is around 2/3's from the bottom, so would that mean its potentially 10 gallons could blow out if nobody's home, or could it be continuous "until it wants to stop", if left unmonitored w nobody home to stop it?
 
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Old 02-08-21, 06:21 AM
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How long was it from when the last person used any water until the relief valve blew?

That time, had someone taken a long shower or was the washing machine run on a hot water wash setting within a few hours before the relief valve blew?

If the relief valve was 2/3 from the bottom of the water heater tank and got stuck ajar by sediment when it blew, it will run water "forever" until the water got shut off, since new water will come into the tank via the dip tube as the water in the upper third of the tank poured out.

More likely the valve would shut again after less than a half gallon of water poured out because by then the system pressure would have dropped below the relief valve trip pressure.

You could shut off the main (cold) water valve before going out to limit the amount of water all over the place if a pipe burst with nobody around.

The expansion tank when properly prepressurized will not sit empty of water. Each time someone used a significant amount of hot water and no one used any water for a few hours afterwards some water will enter the expansion tank due to thermal expansion, and will exit the tank the next time any water got used.
 
  #26  
Old 02-08-21, 02:03 PM
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Your relief valve works on temp and pressure. If your relief valve lets go for either reason it will shut itself off when it lets out enough water to get below those settings on the relief valve unless as Allen explained some sediment got caught in the seat or spring and prevented it from closing then it would continue to leak until the water was shut off.

Has this tank always done this or is it something new and you ever run out of hot water.
 
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Old 02-09-21, 08:53 PM
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only 2 of us in the house, never run out of hot water. Tank started doing this after 1st year of owning it and running it at 140 for the first year.
Tonight I put it back up to 130, we'll see. I know you're tired of hearing about the weather but the black and white undisputable fact is this only happens when its cold, later this weekend i think its gonna hit 18 degrees. I'm hopefully gonna order a new expansion tank to have on hand and do swap maybe just in time for the cold snap.

I would be interested and maybe its a chemistry question for a science teacher..., but the old time plumber saying the colder ground water, makes the burner work harder thus the problem, and the fact that every licensing plumber out my way says you can't have it more than 120, i have no answers why they would be so un-realistic other than what i read is the national standard. Its not a "law", just something they won't deviate from...I still find that very frustrating and ridiculous.
Ive lived here all my life, all life struggled with cold showers likely when dad wanted to conserve on oil, not because the water heater was blowing. Then he'd crank it up and we'd all be hapopy, then crank it down again.
EVEN if it meant more wear and tear on the tank, I'd rather have hot showers than not. This is not a neighborhood where people are putting in exp[ensive re-circulating systems.

Anyway keeping fingers crossed, thanks again



 
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Old 02-10-21, 11:06 AM
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M,
Post #13 second paragraph. You're not scoring many points comparing me to an old plumber.lol

I asked about if you run out of hot water and how long it's been doing this because I have been thinking about a possible problem but it would more likely show up by you not having enough hot water.

The problem I'm thinking of is your cold water dip tube possibly being defective or broken off.

Years ago I ran into this problem with Boch hot water heaters. Boch was getting buried with calls about their oil fired hot waters not producing enough hot water. From what I was told it had been going on for quite a while with nobdy coming up with a solution. Contractors were replacing tanks and it was costing Boch some serious cash.

A friend of mine happen to have one of these installed from a company his father oin law recommended. After numerous calls and no results he gave me a call. He has 2200.00 in service calls invested because they kept saying there was nothing wrong after changing every part including the burner with no results.

With all the info I had to work with I decided to check the dip tube. The tube being made of plastic, was never checked by anyone because they all figured nothing to happen to plastic. As it turned out I unscrewed the fitting from the tank and there was no dip tube. Apparently Boch got tanks with a bad batch of dip tubes installed. I installed a new tube and problem solved.

I called the supply house to make them aware and Boch. As hard as it to believe such a simple thing was not caught it happens I guess. Boch was so happy they sent my friend a check for everyting he spent.

Only getting into the story to let you know why I mentioned your dip tube in the first place. For info purposes what the dip tube does is allow the cold fresh water to start at the bottom of the tank and allow the hot water to get drawn from the top. If you have a defective tube or only half a tube the hot water stays at the bottom of the tank so even though you are getting 110 at the faucet it may be a lot hotter in the tank down near the fire.

Long explanation for just a thought but it goes along with cold weather and cold water. The tank is in the basement, just like the boiler so outside temps have no bearing on the tank where it is the same temp all year round.

Exhausted and done.
 
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Old 02-10-21, 12:39 PM
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Thats a good point, well, how to determine if there's a defective dip tube? This company John Wood is sort of weird when i tried to call them earlier last year, they basically dont have a support line. I think its a canadian company, so basically I cashed in my home depot extended warranty, got a visit by an accountant type person who was not a plumber he said "we're gonna give u a refund" , got a refund and kept the tank (so technically im ahead of the game).
The other challenge here is shower faucets, i went thru this w Delta who for some reason offers a lifetime warranty on very old shower faucets, i thought the shower faucet wasn't mixing hot w cold enough, so they sent me a new cartridge and talked me thru it on the phone. Besides the plumbers telling us to keep it @120, i dont like that a shower faucet mechanism is possibly determining the temp on my shower.
I think the challenge if running out of hot water is only the long run from the boiler to this delta furthest shower.
When I set it to 140 degrees, the delta shower seems fine no matter what. Yes im thinking on a long shower, 15 or 20 mins im likely passing the 30 gallons, of the tank, but it stays hot @ 140 in winter. (in summer it doesnt matter). I have in mind to manually check my gallons per minute output out of the Delta showerr..probably a good idea....to determine if those long showers TRULY are fresh off the burner or what...
(BUT WHEN ITS NOT AT 140 in winter, i frequently reach out and flush the toilet to get more hot shower water, so the delta shower thing is probably not exactly perfect). (which reminds me of another funny plumber mentality line "oh so you like to take long showers"....WTF is that? plumbers dont take long showers? weird breed)
Anyway if there's something about dip tube i should check, lemme know...



 
  #30  
Old 02-10-21, 03:28 PM
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M,
The plumbers keep insisting on 120 to cover their butt. That is what the code is I believe depending where you live. When I worked for the state the limit was 110 which I thought was rediculous since body temp is 98 so it almost feels cold to the skin.

Your shower valve has an adjustable setting on the valve so at least in MA when the plumbers go for an inspection the inspector checks the temp of the waterto meet code. They used to be called antiscald valves and still might be and for the elderly it is a good idea from a personal family experience.

The dip tube is connected to the cold water inlet line on the tank so you would have to cut the cold line to the tank to physically inspect it.

Another thought came to mind. These companies are tighter than a bulls ass at flytime so if they gave you a refund it makes me wonder if they didn't know something was wrong with the tanks but were not advertising it unless you called them.

I went through that with Slant Fin boilers with a tankless. The coils were held in with what turned out to be defective bolts. Instead of having a recall they waited until they failed and then gave you the replacement bolts if you called them but by then they had snapped when trying to tighten them and you had to drill and tap to remove and they didn't want to pay for labor. When I complained about the 6 hrs it took to drill and tap the bolts the only way I got anything was from the supplyhouse. I was doing a lot of business back then and threatened to take it elsewhere so the owner gave me a credit for the amt of labor it took. Slant Fin couldn't have cared less. They have since got their act together and make a good product now.
 
  #31  
Old 02-10-21, 03:56 PM
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Thnx, interesting, about the warranty, it was one of those companies that home depot uses for all products, not just water heaters, i had paid for extended warranty. One other interesting thing about the John Wood 30 gal water heaters presently on home depot site, while there is a price increase from when i bought mine and got my money back, nobody can explain why there are now 2 tanks, one i think around $1100 and the other one like $1300, no details as to why one 30 is more than the other. IT COULD be one is better, I dont know no specifica explanation (of course plumbers say they use a non-home depot john wood tank that only they can get who knows if thats true).
For the consumer purchase the only oil fired hot water storage tanks i can find are the ones at home depot.
HOUSENEEDS website up in VT has the tankless for $2k, tankless oil fired, its like a japanese brand name i've seen around...I was thinking if ever I was gonna invest again in a new tank for $1300 plus labor etc...maybe the tankless oil fired would be cool and likely since there is no storage i guess it wouldnt have this problem.

ON other than right now im ahead if its just a few cold snaps in the winter, and the bucket w alarm prevents me flooding my basement i can probably hoof it out a while. And of course im hoping changing the expansion tank might secure that.


 
  #32  
Old 03-05-21, 08:42 PM
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HI again, so i didnt replace thee expansion tank yet cuz it got warm for a few weeks , until yesterday, sure enough the relief valve on the hot water heater gushed today while running the shower. I didnt have time to try turning on the sink water because the 5 gallon bucket was full by the time i noticed and i didnt want a flood.
So now im gonna change the expansion tank per above discussion. I probably wont know if it works until next winter, depending how much is for us in NY, long island.
Anyway the Amtrol i think link you sent above, when im shopping they werent in stock, but i found Watts, is that just as OK? Also how come it seems Amtrol descriptions don't use the "phrase" pottable water? (watts and some others do).

Tnx again
 
  #33  
Old 03-05-21, 11:21 PM
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PS. Tonight's relief valve blew a 2nd time, i had forgot to put the alarm back in the bucket, so it flooded the whole basement...
im thinking for sure i should replace the relief valve too, under the circumstances and the amount of water im thinkin the relief valve may be shot/stuck from too many releases. i probably replaced it last winter in thick of initial problem,
See my prior question abotu expansion tanks, and since im gonna try it right this time, should i maybe just grab the same tank from home depot or stick with the mail order ones like amtrol or watts?

tnx mike
 
  #34  
Old 03-06-21, 04:54 AM
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Ŕmtrol tanks for potable water are white or cream colored and go by therm x trol tanks and have a 3\4” male thread vs a 1\2” for heat,
 
  #35  
Old 03-06-21, 01:07 PM
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Thanks SPOTT. so i decided to order the AMTROL you linked above. We spent enough time chatting here, i figure stick w the plan you all have suggested. I have a feeling AMTROL is american made too which might help.
Probably because of winter home depot and loews are low on stock on their off brands so what the heck.

I left the hot water heater "off" overnight, after i cleaned up the flood, (finished basement, piano, etc...equipement there).....I turned it on to take a shower , successfully. now im gonna turn it off thru next shower time.

a $50 part, plus maybe i should buy a TP valve anyway (its not leaking now, it did what it was supposed to) but
this would prob be a $350 job with a licensed plumber.
The way im thinking is IF this happens again, after new exp tank, then maybe i should use the money warranty gave me and buy a new 30 gal tank.... OR get one of those japanese tankless oil fired things and spend a little more.
I kinda already know im not gonna find a licensed plumber who would "guarantee" i can run at 140......degrees. sure they'll sell me a whole new system for $2500 im sure, but they're gonna throw in the disclaimer of 120 degrees...the tankless japanese brand is $2000 for the part...

one step at a time, see what happens with the tank. GOOD NEWS is last nights TP VALVE release, the weather was not TEENS. it was 33degrees F, finally so 1st time it happenned above "teen" temps..

We're never gonna know if my old 30 gal tank is shot unless i replace it, cut it open and look..so its really trial and error.

One last question, one vid on youtube said about TP/valve, make sure you buy the correct one to replace it? how do i know which is the correct one? The one thats there i bought based on homedepot floor people, the unit originally was installed by local hobbyists...any way to fact check the "correct" t/p valve?




 
  #36  
Old 03-06-21, 04:10 PM
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https://eportal.hotwater.com/Commerce/PartsList#web-app

This is the part from the serial number on your tank. You can look up John Wood oil fired tanks sight or call John Wood with the info.

You want 210 deg/ 150 pressure.

https://www.johnwoodwaterheaters.com/en/products/oil-fired
https://www.supplyhouse.com/AO-Smith-100108279-0-62-Residential-Orientation-T-P-Relief-Valve-Only-Model-TP-100?gclid=Cj0KCQiA7YyCBhD_ARIsALkj54ruaiX1_jtV9ybP7I30kzW-AMD4xfPBbE7LnpCfKKD4OpAGL--1s1UaAhdHEALw_wcB

 
  #37  
Old 03-06-21, 06:20 PM
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Just a few comments here. The first thing that bothers me is the relief valve is 25 years old. You must replace the relief valve anytime you replace a water heater. The relief valve for oil fired water heaters should a 40XL. Make sure the insertion is long enough to be in the tank. For instance a 40XL-8 has an 8" insertion. I really do not believe the tank is the problem, I have used those tanks without an issue. Maybe the water pressure in the street is a bit higher than you may think, gage it. Is the tank on the cold inlet, not that it affects the operation but does affect the longevity.
The truth of the matter is as it gets colder outside the incoming water temperature does drop. When that happens you do have more expansion as you raise the water temperature.
I would start by changing the relief valve with the proper one and proper insertion. It should have come with the new tank.
 
  #38  
Old 03-06-21, 06:53 PM
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Does mikecat riello boiler have a tankless coil?

When installing new expansion tank put 1/2" ball valve on it to simplifie depressurization.

Hot water at 140F is dangerous. 120F is common max DHW temperature.
A hot water tempering valve is simple safety addition:
https://www.supplyhouse.com/sh/contr...empering+valve
 
  #39  
Old 03-08-21, 11:35 AM
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hi all
1-spott. seems like i got the right relief valve then and been having the right one.

2-rbeck. sorry if i confused anybody relief valve is not 25yrs old (the riello burner and the aquastat might be 20 yrs oldish, but i've verified the temp at faucets to be accurate so far) , The Tp Valve was changed last winter, probably twice, now i bought a new one at home depot. Rbeck, yes speaking to my town water supply best they could tell me is we are at 60psi, but on cold quiet nights it could go up to 70psi. I got the new Amtrol tank by mail today, so unless someone tells me otherwise here, im gonna set it to 60psi when i install it i dont know if 65 would be better if truly coid nights do peak at 70 but for now 60 unlless one of you insists. .

3-Doughness, i dont nknow what is a tankless coil. I have riello burner with John Wood 30 galllon tank. I und about 120 deegree part of my concerns here is there will only be cold showers in this house if water is at 120, on cold weather nights...its just a fact all my life. 130 seems to be pretty effective, 125 survivable. Plumbing standard usa is 120, but i've yet to find a homeowner around here who keeps it at 120. thought i dont know if they are oil or gas or if that matters. mine is oil.

the new amtrol tank came, gonna work up my nerver and swap it out hopefully this week, see if that helps.

tnx



 

Last edited by mikecat; 03-08-21 at 01:57 PM.
  #40  
Old 03-08-21, 02:49 PM
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m,
This is just opinion but as you said yourself, your problem happens in cold weather. I would set the tank to 70 psi. It will do no harm and then if you want to lower the charge you can just release a little air. Much easier to lower it than to have to isolate it and raise the pressure.

If the tank is the problem you might not need to change the relief valve. After all it's only doing its job.

Just my thought.
 
 

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