I have an oil fired burnham boiler, with an attached Watts ET-60 expansion tank.

Toward the end of the heating season last year, the boiler was emitting water from the overflow, on an intermittent basis.

We have run the boiler 3 times this year and on each occasion, water has run constantly from the overflow.

The boiler pressure is about 20 PSI and the water temp peaked about 190-200 on the most recent run today.

The expansion tank has a pressure valve (like that found on a car or bike tire) and the pressure in that, on the air side is 12-14 PSI hot or cold.

I suspect it is the expansion tank, but am not entirely certain.

Anyone have a suggestion?

Thanks in advance, Terry

 

It is likely one of two things.
Lack of air pressure in exp tank or ruptured expansion tank membrane.

You need to measure the air pressure of the exp tank with no static pressure in the system. The water needs to be drained from the furnace until the furnace gauge reads 0 PSI.

Then remeasure the pressure at the exp tank and if it is very low, pump it back up to 15 PSI. If you cannot repressure it, then the membrane is ruptured and the tank must be replaced. Make sure you leave a bleeder valve on one of the radiators open while you attempt to repressurize the expansion tank, so that you are really pressurizing the exp tank and not the plumbing.

I have two ET-60 expansion tanks on my furnace and the air does leak out over time and they need to be repressurized occasionally.

 

reno is right on...

You need to turn off the water feed valve to the boiler first though.

I might recommend instead of leaving a bleeder open, drop the boiler to 0 PSI, check the tire valve on the tank ... put air in with a pump or compressor until you have 12 PSI. Look at the boiler gauge again, and if it has crept up a bit, open the drain again to drop it to zero. Recheck the tank. If it's a little low, put in a little more air. Repeat until you have 12 PSI of air in the tank, and zero on the boiler.

If any WATER comes out the tire valve, you need to replace the tank.

Those tanks lose about 1 PSI per year according to manufacturers. They should be checked as preventative maintenance yearly. You can NOT check the air pressure in the tank with any pressure at all on the boiler side. You won't get an accurate reading.

 

Thanks very much for the feedback.

I did bleed a little air off of the tank the other day and it was dry, no water at all.

I'll check the pressures using the methods you suggested and report my findings.

Terry

 

So, the tank is probably fine, but by letting any air out, you compounded the pressure problem... so get that air back in and you should be fine.

 

Here is what I have done.

I ended up draining the whole system.

The pressure gauge on the boiler still reads about 15 psi, it has not moved at all, so I suspect it is whacked.

If I tap the expansion tank, I can hear a difference in the tone between the top and bottom.

I tried putting some compressed air to it, and I can hear a little gurgling when I do, but I'm afraid of putting too much pressure in it and rupturing the bladder inside.

The reading I get off the tank barely moves my pressure gauge when I check it.

I'm considering removing the expanion tank and draining remaining water in it and then re-pressurizing.

Arrgggghhhh, at this rate, I had better call a plumber....

 

Dude, yer making a whole lotta work for yourself !

You didn't need to drain the whole system, and in fact should NOT have. When you refill it, it's gonna be a major PITA to get all the air out. Fresh water contains TONS of air that will come out of the water once it's heated. All you should have done is what we told ya to done.

Yes, the gauge is pooched. Since you are drained, replace it now.

Use an accurate tire gauge on the air fitting, you should have no trouble reading 12 PSI with a tire gauge.

Putting air in that tank is no different than putting air in a tire. Does your compressor have a regulator on it ? Turn it down to 12 PSI and you can't possibly put too much air in.

If the tank IS bad and has water in it, it will be HEAVY when/if you remove it, so BE PREPARED for that! Don't drop it on yer toesies.

If you do remove it, and put air in, if you hear any air noises at the water connection end, replace the tank.

 

Agreed, it was a lot of work.
I thought I was doing as you suggested.

In my situation, I have the main water supply which is connected to my water service. I first turned that off.

Then I have 3 shut off valves connected to the boiler.
I closed those as well.

then I opened the drain valve at the bottom of all this.

the water started coming out, and it was also draining the whole system. I had no other way to control this it appears.

Anyway, it is drained and I put in 12 psi into the expansion tank.

I have refilled and bled all the rads (yes I realize I will need to do it again, but it does not take that long now that they are filled.) and when I went back down to double check, the overflow was running like a tap.

with all the rads now filled the pressure on the expansion tank is 20psi.

Could it be the pressure relief valve is the culprit after-all?

Again thanks for the help, I do appreciate it.

 

Since your gauge is NFG , you would have had no way to tell when it got to zero anyway I guess! Sorry, we should have been clearer that all we wanted you to do was drain enough water to get to zero PSI on the gauge, and no more.

Measuring the pressure on the tank when there is pressure in the boiler tells you nothing about how much air charge is in the tank. You will not get an accurate reading unless the water side of the tank is at zero PSI ...

Do this:

CLOSE the water feed valve to the boiler.

Hmmmm... you have no pressure gauge... or did you get a new one ? Without a functioning pressure gauge, you have no way of diagnosing your problem. ...anyway,

with the water valve feeding the boiler closed, open a drain and let out only enough water to get the boiler pressure to 12 PSI. Leave the feed valve closed.

Run the boiler and watch the pressure on the gauge that you don't have. See if it stays in range (between 12 and 20) with the feed water valve closed. If it DOES, then you may have a problem with the feed water regulator valve.

If the pressure relief valve is over five years old, replace it ANYWAY... just as a preventative maintenance item.

 

Oh... one more thing I forgot ... tapping on the tank and listening for 'hollow' sounds is NOT a reliable or acceptable way of determing anything.

First things first:

Replace pressure gauge.

Replace relief valve.

When that's done, we'll continue...

 

I agree with NJ Trooper, if the water gauge is not working properly we don't know if the problem is the expansion tank or the water regulator.

I had an old big red Muller regulator on my boiler and the pressure crept to 35 PSI every week or so and I got overflow periodically. I replaced it with a Watts regulator unit and problem was solved.

The good news is all these boiler parts are relatively cheap.
The ET-60 cost me well under $100 seven years ago.
A Watts regulator, pressure relief valve and one way valve, cost me a grand total of $50 seven years ago.

The ET-60 lose about 2 PSI per year based on my experience. When I converted my system from an oil boiler to an electric boiler, I checked both ET-60 which were at 16 PSI in 2001. They were at 1 and 2 PSI this year. It takes a good 15 to 20 minutes with a bicycle pump to refill them.

 

I connected a pressure gauge to the drain on the boiler via a hose.

I get 20psi that is no heat, no pump running, just the main supply line open all the way and everything else as it should be.

So I guess that means the inlet regulator is only allowing 20psi
of pressure from the street into the system?

BTW I also discovered I have a backflow preventer between the main shut off and the regulator.
This is just an FYI.

I'm headed out to pick up an overflow valve and a new pressure / temp gauge.

Terry

 

Hi, I just had a similar problem happen to me today: relief valve opening. The technician from my oil company determined the ET-60 tank was full of water.

While I don't know how old the tank was, as it was here when I bought the house, I think it is less than 10 years old. How long do these types of tanks normally last?

And what types of situations lead to a life span shorter than normal?

I'm wondering if I did anything, or failed to do something, that would have shortened its life span. What do I need to do on a regular basis to maintain the tank?

reno1962, would I normally have to pump it up like you did for yours?

Thanks in advance!
LA

 

La_koala,

The weak link in ET-60 is the rubber membrane.
I don't know the typical life span of the ET-60.
My original old-fashioned expansion tank (no rubber membrane) lasted nearly 50 years.

Routine maintenance is the best way to prolong the life of the tank. It should be check every 2-3 years with a tire gauge to make sure the pressure is between 12 and 18 PSI for a 2 story house. If the pressure is low it should be pumped up to around 15 PSI with a tire pump.

I only noticed the low pressure on mine when I was doing some other work on the heating system. But I will check my pressure from now on every 2 years.

 

4:45 pm here in Toronto.
I just installed the new pressure relief valve and a new pressure/temp gauge in the boiler.

I have to admit, I got a little wet changing the gauge, but thankfully I covered a lot of things in advance and I discovered that water even at about 20 psi and a small opening has a lot of punch!

right now the pressure on the expansion tank is 12 psi.

The gauge I installed on the boiler has not moved, so that has me a little confused.

The water has not been turned back on yet, I await my next command.

 

I am assuming the following:

1) The supply valve is turned off
2) The ET-60 has been repressurized to 12 PSI.
3) The boiler is partially drained and so the water gauge is correctly reading at 0 PSI.

If this is the case, I would turn on the supply valve and bleed all the radiators. The water gauge will slowly rise and hit 12 to 18 PSI.

Then I would fire up the boiler and see if the overflow problem is solved.

 

boiler is running right now....stay tuned.....it was 62 deg in the house, so it will take a moment to get back to 68 or so.....

 

temp in the house is 66 right now.

water PSI is about 21 water temp 175 degF

So far, no water has discharged from the overflow.

A friend of mine was saying to heat the house now, record the water pressure before I go to bed, turn off the furnace over night and then read the water pressure in the morning to confirm if the water inlet regulator may be the culprit.

He says if the water pressure rises overnight, that may indicate an inlet regulator problem.

I keep ya posted, don't want to get too excited about this until all is confirmed.

 

OK, we seem to be going in a few different directions...

Ice, you will still read 12 PSI on the tank, even if there's NO pressure in the boiler. BUT, you can't measure or adjust the air charge on the tank if there is ANY pressure in the boiler.

If you are reading 20 PSI on the boiler when it's COLD, that's too high. If you've got a normal one or two story home, a COLD boiler should read no higher than 15 PSI.

I know what your friend was trying to say, let me reiterate...

CLOSE the water feed valve.

Let the boiler get cold.

Open a drain valve and drain some water to drop the pressure in the boiler to 12 PSI.

With the feed valve still closed, run the boiler up to 180°F, and watch the pressure. It shouldn't go over 20 or so ...

Now, let the boiler cool again... all the way.

Open the feedwater valve and watch the pressure gauge. Depending on the adjustment of the feed water regulator, you may see a slight increase, or it may not move at all.

If it increases above the 12 PSI and levels off and STAYS below (still no fire please, cold boiler!) 15 PSI indefinitely, then leave it alone. If it goes above 15 PSI and STAYS at something higher, it needs to be adjusted. If it goes above 15 PSI and keeps on creeping higher and higher, it needs to be replaced. If it does need to be replaced, you can close the feedwater valve and let some pressure out and run the boiler with the valve closed for a short time until you have a chance to replace the regulator, but while you are doing this, keep a close eye on the pressure... if you have a leak you run the risk of running without enough water, and that can cause big problems!

For a 2 story home, you never need more than 15 PSI on a cold boiler.

For maximum longevity on the expansion tank, the less the bladder has to flex, the longer it will last. The pressure should be checked and adjusted in the tank at a minimum of every 2 years. I recommend checking it every year. Just keep in mind that you can NOT check the pressure on the tank if there is ANY pressure in the boiler, and tapping on it will tell you little or nothing.

 

Latest news.

House now 73 deg (I had thermostat set to 70 in error)
Water temp was up to 200 and the pressure was hanging at 30.

PRV did not release.

I suspect the problem may not be resolved.

 

I 'spect yer right... in fact, I know it...

So, do the test in my previous post.

You may have two problems, one you fixed by charging the expansion tank, but that was only a contributing factor.

The other, you still need to diagnose... so do the test.

 

this morning the water psi on the boiler was 15 psi.
The water temp around 70 as it is in the house.

Not sure what the temp was overnight, but there is a layer of frost on everything outside, so it was cool to be certain.

I'll start doing the tests shortly.

Thanks, Terry

 

Hi reno and NJ Trooper, thanks so much for your responses about checking and maintenance of the diaphragm expansion tank and longevity of the rubber diaphragm. I would guess that mine was not checked every year by the previous owner, as the house was empty for about two years before I bought it.

I sort of wish we had the old-style expansion tank though. It seems that regular maintenance on those have them lasting many years. When the previous owner installed the newer boiler, they must have changed to the diaphragm type, because I can see the old expansion tank sitting in the ceiling of my basement still. Maybe they figured the diaphragm type would be less maintenance for them.

Thanks again! I just found these forums and I'm very impressed with the knowledge you have and are willing to share.

 

Here are the results so far.
This morning (friday).

I shut off the main water supply and released water from the boiler through the drain at the bottom until the water pressure in the boiler reached 12 psi.

With the water supply line still closed, I ran the boiler.

The temp reached just shy of 180, but the pressure had risen to 24 psi after hanging at 20 for a long time.

I have shut the boiler off and have let the pump run allowing it to cool gradually. I will try the balance of the test after the boiler has cooled.

Since my local plumbing supply is closed on Saturday, shall I go and buy a regulator and expansion tank and have them at the ready?

Thanks, Terry

 

No koala, you don't ... the newer tanks are MUCH better than the old style. What would ya rather do ? take 5 minutes and check the air pressure in the tank every year or two ? or constantly be going around bleeding air out of your system, and then every year or two having to drain that big ole tank with a hose ... cuz, ya see, proper maintenance on that big ole tank is more than the new style...

Ice, I believe that your existing tank is OK. It does sound as though it may be slightly smaller than you need. From what I can gather, you have cast iron radiators, and a large volume of water in your system. You may have noticed that reno has TWO ET60 tanks on his system. He probably also has a large water volume system, and needed the two tanks to provide enough expansion room when the water was heated.

When you take water from room temperature to 180°F it will expand in VOLUME by a bit less than 4%. This means that for every 100 gallons of water, you will need room for expansion of 4 gallons. I can't imagine that you have more than 100 gallons, and would think that the 60 should do the job, but it might just be marginal. IF you do decide to replace it, I MIGHT suggest you go to a 90, or a 60 and a 30, or two 60's.

Tell us about the heating system. Huge pipes ? cast iron radiators ? etc ?

24 PSI is actually not too high. If you approach 27, THAT is too high.

Let's hear the rest of the test results...

 

NJ Tropper,

You are correct. I started with one ET-60 and found the PSI was on the high side (high 20's) when the boiler hit peak temperature (180 F). I installed a second ET-60 and the PSI dropped to the low 20's at peak boiler temperature.

I have 6 cast iron radiators and 3 finned radiators.

 

I'm back.

I checked the psi this morning and it is now 15psi.
It was 12 psi at 6 pm last evening.

I turned the circulating pump off and it may have been my imagination, but I think the gauge moved just so slightly.

Water is around 65 deg. The boiler did not run overnight.

My house is 1850 sq ft, 2 story.
Upstairs has 3 rads, downstairs 7, of which 3 are behemoths.
All rads are cast iron.

All the pipes are iron about 1.5 od, once they get away from the boiler and the pipes running through the basement are still insulated in nasty asbestos paper, which I will have removed in the future. The basement of the house is unfinished and does not have any rads in it, so it gets chilly down there.

The boiler is a BURNHAM, model number PU73W2TBWF3 low pressure type, oil fired. DOM is 1998

It's possible there was a different type of system (steam?) here when the house was built, because there are capped off pipes sticking out of the wall in my closet on the 2nd floor. Perhaps the old system had the expansion tank in there at some point?

I also suspect there was a coal fired operation in here as well, along time ago, because I find chunks of coal in the basement from time time to time, on top of beams and such, but that is another story for another day.

So what is the verdict?

Thanks, Terry

 

OK, you've done most of the testing, but I've copied the last part from the post above and pasted that below ... that's what you need to do next.

So far, you've determined that you can fire the boiler up to 180 without the relief valve opening, and that your pressure hits 24 PSI ... which is _OK_, but still a little high. You _may_ need more expansion tank capacity, assuming that your existing tank is indeed intact and that you properly adjusted the air charge to 12 PSI. You can probably live with what you have, but if the tank size is marginal for your system, it means you will need to be diligent about maintaining the air charge in your existing tank.

Next, by closing the manual feed valve and letting the boiler sit cold overnight, the pressure creeping up 3 PSI could mean that your manual feed shutoff valve does not close tightly... NOT a big problem, as long as the feed water regulator is working OK, which we will test next by continuing the diagnosis from above.

===== copied from above post, edited for clarity ======

(still no fire please, these tests on a cold boiler!)
(I know the house is cold, but patience is a virtue, and it is the only way to diagnose this problem! Send the kids to Grandmas!)

Open the feedwater valve and watch the pressure gauge. Depending on the adjustment of the feed water regulator, you may see a slight increase, or it may not move at all.

If it increases above the 12 PSI and levels off and STAYS below 15 PSI indefinitely, then leave it alone. *** see notes below ***

If it goes above 15 PSI and STAYS at something higher, it needs to be adjusted.

If it goes above 15 PSI and keeps on creeping higher and higher, it needs to be replaced.

If it does need to be replaced, you can close the feedwater valve and let some pressure out and run the boiler with the valve closed for a short time until you have a chance to replace the regulator, but while you are doing this, keep a close eye on the pressure...

==== end of copy from above ====

*** note *** Since your tank _may_ be marginally sized, if you determine that the feed water regulator is working OK, if it levels off at any point ABOVE 12 PSI, I am going to recommend that it be readjusted to lower the cold pressure down TO 12 PSI. This will give you just a little bit more 'headroom' on the top end for expansion and may obviate having to add a larger, or second, tank.

*** second note *** it can sometimes take HOURS for the regulator valve to level off at it's setpoint, so BE PATIENT!

By the way, you _may_ see the pressure gauge wiggle a little bit with the starting and stopping of pumps... so don't be concerned about that.

 

I missed a step in my previous reply.

The water supply valve was open all night, so the pressure in the boiler went to 15 from 12 overnight.

I just checked it again and it is still at 15 psi, no pump running, no heat.

I will continue to leave the water valve open and check the PSI again in a few hours.

So, it appears at the very least the regulator will require adjusting to 12 from 15, provided it does not creep upward in the next few hours?

Terry

 

If you are holding steady at 15 psi cold and do not exceed 25 hot then I suggest that you do nothing until spring. With cast iron radiators and probably large distribution piping you most likely have an expansion tank that is minimally sized for your system.

It won't hurt a thing to run at 20 to 25 psi. Fall and winter is the time to work on cooling systems and spring/summer is for heating systems. Unless you have other problems don't mess with it.

 

I'm gonna go with furd here... it does sound like the regulator is adjusted to 15 PSI and is holding. A two story home could need 15 PSI depending on the actual height from the boiler to the highest radiator.

Next step: Do diligence. Just watch it and see how it behaves.

 

Hello again:

I just checked the water pressure and it is still 15 psi, it has not moved all day.

I will watch it and keep the thermostat at about 67 at all times, to avoid long catchup cycles to see if that helps.

Thanks very much for all your help, I greatly appreciate it and I'll let you how it goes.....Terry

 

I just ran the boiler again to take a little chill off the house.

It went to 165 deg and 25 psi.

My friend, whom also has experience with this type of thing is suggesting there is still something seriously, or as he likes to say "whacko" with the system.

He says the PSI should not go up more than 2-3 psi and the boiler should not get hotter than 145deg.

 

I believe that 2-3 PSI is wishful thinking ... my personal limit is 8 PSI ... on a system such as yours with a large water volume, you would need MONSTER expansion tanks to keep the pressure rise down to 2-3 PSI ... that's a fact.

Is your expansion tank installed such that it is hanging vertically from the pipes ? And the air valve is pointing DOWN? If your tank is installed any other way, that test of checking for water from the air valve may not be valid.

You may still have a problem with that tank.

The only way to check is to again drop the boiler to ZERO, but drain ONLY ENOUGH water to get to zero. Put your tire gauge on the air fitting and see if you still have 12 PSI that you put in the last time. EVEN IF YOU DO HAVE 12 PSI, it IS possible that the bladder is ruptured and there is more water than air inside that tank.

How old is the tank anyway ?

If the pressure holds indefintely at 15 PSI when the boiler is not firing, yet continues to climb when it is firing, then the only thing that could be wrong is that the expansion tank is toast.

Why 145° ? The high limit is set at 180°, and it would not be at all uncommon for the boiler to reach that high limit on a regular basis. Perhaps not so much during these warmer seasons, and maybe that's what your friend is thinking ... fact is though that the temp the boiler reaches is dependent on a few things, the outdoor temperature, the amount of radiation in your home, and the heat loss of the home, to name a few.

 

"Is your expansion tank installed such that it is hanging vertically from the pipes ? And the air valve is pointing DOWN?"

That is correct, the air bleed is on the bottom pointing down.

"How old is the tank anyway ?"

The boiler was built in 1998, so I would presume the expansion tank is the same age, there is no date of manufacture present the tank.

The PSI in the boiler has been holding steady at 15 cold for 2 days now.

I will do the test for the expansion tank tomorrow and report the findings.

Terry

 

I drained the boiler of water until the gauge was well and truly zero.

I turned off the water supply as well.

I vented a couple of PSI from the expansion tank and the air out of the tank is bone dry.

The tank before venting was 12 psi.

I have re pressurized it to 12 psi

verdict?

 

If the feed valve is holding 15 PSI indefinitely.

The expansion tank is dry and holding 12 PSI indefinitely.

There is nothing wrong with the components.

But your postings seem to indicate that each time you fire the boiler, the pressure seems to go higher and higher ? correct ?

Nothing is consistent here... one day you have 21 at 175, then later 25 at 165 ... then, at 180, you had 24 ...

If the relief valve isn't spewing, just run the system ...

If the relief valve spews when the temp is very high, in spite of the fact that you have pressure in your tank, and the cold pressure is correct, it tells me that your tank is undersized.

You could try adjusting that feed regulator down to 12 PSI to give you just a little more headroom, which model valve do you have on your system ?

 

the inlet regulator is a Watts 1156F

Terry

 

Unscrew that fast fill lever thing from the top of the valve and set aside.

Lift out the little rod inside the hollow adjusting screw and set aside ... DON'T LOSE IT !

Loosen the locknut on the adjusting screw.

Using a dime turn the adjusting screw one full turn counter-clockwise.

Drain a wee bitta watta from the boiler to drop the PSI to 10 and see how far it comes back up when you close the drain. Be patient, give it a few minutes to settle at the new adjustment... still above 12 ? do it again ... lather, rinse, repeat, until it's sitting pretty at 12 PSI.

Snug the locknut, drop the rod back in and replace the lever cap .

The alternate to this is to leave the regulator alone, and run the system. As long as the pressure stays below 27 PSI, you are fine.

You could also replace the 60 with a 90 if you have room ... or tee another 30 or 60 onto the system.

 

Opening up this thread again.

Having more high pressure high temps again, was getting worried that I was going to have trouble.

Called the plumber (old school guy, been at it forever) today.

He first changed the expansion tank, ran the boiler watched the gauges and left said was all good now. (old expansion tank was full of water at the top, when he bled air out from the bottom was bone dry as far as I could tell.)

He leaves, boiler is on, then I hear the sound of water gurgling, overflow is spewing.

Pressure over 30.

Call him back, he now thinks the pump is the culprit. It is really hot, sounds like it is running. He thinks it may be overheating and slowing down.

Changes the pump to a 3 speed GRUNDFOS, runs it, says all should be fine now, he leaves and now I see the pressure building again to almost 30, I shut it off before it spewed.

Water supply was turned off, all rads bled of air.

What next the regulator?

Thanks, Terry