mystery problem, need thinking caps

[Deleted User]

either pull the check, or crack the bypass and your problems should go away. Chances are slim that the new fill valve is bad, unless you got osme teflon tape under the seat.

ME

Ted_9

Pool Heater\",I ran into the same type of boiler. It was just a pool heater.

GW

mystery problem, need thinking caps

Fellow wall people, I'm humbled to come before you because I consider myself an above average hydronics craftsman.

Here is my pain, please show me to the medicine. The little boiler shown here entered my life a couple of weeks ago. The circ puked so I replaced it. While it was dysfunctional, the boiler was rocking and rolling; boiling inside and threatening to self destruct.

A call came in a day or two later saying the puker is leaking by. I noticed it was a 100K btu boiler with a #15 compression tank, so I recommended replacing it with a #30 and installing a new puker.

Then a call comes in a day or two later that the feeder is leaking out of the stem, an unusual site in my opinion, but I nicely explained it must have happened while the 'lil boiler was huffing away when the circ had dropped.

A day or two later she calls and says the relief is still dripping water into a now-well-placed bucket. I cruise on down and check the water pressure at the water heater, it's about 110. I set up an appt. for a PRV to be installed.

We get the PRV installed, and the next day I get another call, and you guessed it, water in the bucket. I noticed the water pressure went from 15 to 20 when the circ/boiler started, and only imagined the ghost of the 'lil boiler could only possibly get it up to 30 in the middle of the night, even though the new PRV was installed. (No expansion tank on the domestic, at this point anyway).

So I back the pressure on the feeder to 10 (just a tiny cape like house), notice it go to 15 (as expected due to the pump's position), and I thought I'd be done with 'lil boiler.

I stopped by today as a good faith measure (she actually left me a key when she took off for the holidays), and my jaw dropped when I saw water in the bucket. The pressure was up to 25. Dr Phil, can you help me and 'lil boiler? Notice the rather crude piping arrangement, there is actually a scoop on the RETURN of all places, the two Taco zv's are on the supply. I'm open to the possibility that the feeder/relief/#30 can be defective, but I just can't get myself to change them out with some logical reason. After all the system worked fine for years until the old circ dropped. It is the mystery of the rising pressure.

Gary

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rick_33

dOES CUSTOMER HAVE CITY PRESSURE. iS IT HIGH. SEEN VALVES NOT HOLD UP SOMETIMES LET US KNOW.

Dan C.

I had

I had a similar problem with the exact same boiler and I opened up the bypass valve halfway which is closed in the picture you posted. i don't know why but it sefinatly solved the problem.

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GW

city water

Yes, like I mentioned it is/was high. We put a PRV on it to lower it down. So I'm still stumped.

Gary

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GW

By-pass

It was closed when I arrived on the scene, but if anyone out there tells me that is must be cracked a bit, I'm all ears.

Gary

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Jason_22

Question?

Is that a new s1156f feeder? I believe the only way, at this point that that boiler can be building pressure is if water is "creeping" in thru that feeder.

jeff_51

this is why we don't use feeders

just a watts 9-D (req'd) and two isolation valves always off. Too many scenario's like you just posted

Weezbo

I can see economical...

Buh not evena valve on the fast fill line ,Wow that is not a great idea. how about taking the strainer off the bottom of the fast fill and blasting it clear from time to time? no valve you got to be pretty quick about it.where did the screen go!? o! dambbit gumby ! it is hiding in the floor drain clear across the room now....lots of fast fills the diaphram gets a bit of debris bingo ! you got perpetual automatic fast fill.

Man! i type slow *~/:)

Glenn Harrison_2

Gary, this might be a stretch BUT,

If the unit was fine till you installed the pump, let's look at the pump. Am I correct that that is a IFC (Internal Flow Check) Pump. If it is, and I will assume the old pump did not have a check valve in it, I would pull the check valve out of the volute. I know it sounds wierd but that looks like a copper fin tube boiler and those are a little finicky with flow.

The only other thing I can think of based on the location of the air scoop is, Is the pump in upside down for that particular unit?

After that, I would be closing the valve on that feeder valve and let it run for 24 hours and re-check it, as it could be that the new feeder is bleeding thru and raising the pressure.

GW

yes, new 1156

Could it be bad?

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GW

that's strange

I have NEVER had this problem! My lucky day I guess.

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GW

reply

I'm ashamed to say I grabbed the 007 off the shelf and installed it w/o looking if it was an IFC, but even if it is an IFC, I fail to see what difference it would make. We have plenty of flow; if the flow was lacking I would certainly suspect a possble IFC issue.

I don't know what to say about the circ position, but it is point down into the boiler (circ is on the return)

I've never experienced a bad 1156, can it happen?

gary

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Tony_23

That circ

looks like an IFC007. Your expansion tank is on the return on the opposite side of the check from the relief valve, hence isolating the #30 from the hot boiler on shut-down. It'll only happen once both ZV's close and the circ stops, then the residual heat in the boiler expands the captive water popping the relief.

Shoulda just used a std 007

Tony_23

I type slow, look down

Jason_22

OH YES

brucewo1b

Which is why the sujestion to crack the bypass makes sence

Jason_22

good eyes tony!!

Tony_23

The bypass would help, yes

and if it's there, and the boiler is copper, it should be full open too.

If losing the circ makes it howl at the moon, it should also have a flow switch

Glenn Harrison_2

I'm more concerned with...

what happens in the boiler when the check valve closes with the pump off. Is it somehow trapping heat in the boiler in the off cycle causing the pressure to build in the fin tube HX? Also, it isolates the expansion tanks in the off cycle with the zone valves closed. I don't know for sure, but I see it as a possibility. When ever I have a situation like this, I always like to sit back and go, what is different now than before. From what I see, the pump is different, and I'm almost positive that the pump is an IFC model, which would meen the check valve is different from the way things were before this all started.

I figure the pump is flowing in the right direction, but I thought I would throw that out there as a possibility. Even you said its very strange the air scoop is on the return. Maybe it's supposed to flow upward instead. Hey, I've did it once. Pulled a pump, put the new one in the way that made sense, and turned out I had installed it backwords for the particular unit I was on. It's just a thought.

As far as the feeder, all it takes is one chunk of dirt damaging the diaphram in that valve, and it is bad. It's a mechanical device dealing with water. If it can fail, it will, even tho it's brand new. That's why I said close the inlet valve to the feeder and see what happens, assuming of course there is a inlet valve and it still shuts off 100%.

Glenn Harrison_2

Tony, you don't type too slow

as you came up with the final answer before I put 2 and 2 together and finished my train of thought. Good catch on the valves. I knwe I was on the right track, I missed the zone valves on my first post.

Tony_23

well, thanks

I'm less than average typist, but maybe above average troubleshooter I try to stay humble.

GW

makes sense

So, you're saying the ifc keeps the 30 from seeing the boiler, as do the the zv's. But, how do you explain the increasing pressure? How can it go from 10 or 15, up to 30?

I'll certainly swing by and ditch the ifc gizmo, but could the feeder be bad?

Thanks,

Gary

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Glenn Harrison_2

Because you still have heat trapped

in the burner compartment, and that fin tube can absorb a lot of residual radiant heat left over in the burner compartment. At that point you are still heating water in a closed vessel with absolutly no room for expansion, and no expansion tank in the picture.

And yes, the feeder could be bad too. If you want to play it safe, remove the check valve and replace the feeder. Then you know your gludious maximous is covered.

Ted_9

Pool Heater

> in the burner compartment, and that fin tube can

> absorb a lot of residual radiant heat left over

> in the burner compartment. At that point you are

> still heating water in a closed vessel with

> absolutly no room for expansion, and no expansion

> tank in the picture.

>

> And yes, the feeder could

> be bad too. If you want to play it safe, remove

> the check valve and replace the feeder. Then you

> know your gludious maximous is covered.





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S Ebels

Hard to be humble

When your as sharp eyed as you are. After studying the pic, I have to agree with your diagnosis. Ya gotta think like the water!

Paul B._2

Pressure increase

I think Tony has the right track here, with the IFC isolating the boiler from the expansion tank, only I think what's happening is when the boiler cools the water in it contracts, and since the boiler can't "see" the expansion tank a partial vacuum forms, allowing the feed valve to add a little water.

If you look at the photo and imagine the IFC closed and the zone valves closed, you can see as the boiler cools the feeder is going to be right there to stuff a little more water in.

Over the course of a few cycles you'd have enough water added to the system to cause the pressure to rise once the water is heated up to the limit setting, allowing the relief valve to do it's job.

That' an older style Mini Therm, and depending on the zone flow rate the by-pas valve may need to be open slightly. Does it knock or howl when it operates?

Give me a call in the morning at 603-335-6300x562, and we'll see if we can't figure this out.

Paul B.

Anthony Menafro

Trapping pressure

Gary, you are absolutely trapping the pressure between the closed zone valves and the check valve on the pump based on the residual heat built up in the boiler's heat exchanger. You must also leave the yellow handled ball valve(balancing cock) cracked open a wee bit. It will allow equal pressure between the supply and return, but more importantly, stop any thermal shock to the copper heat exchanger due to the difference in temp. between the hot supply water and the cool return water. Good luck.

Anthony Menafro

Steve_35

The pressure goes up because

there's no place for the water to expand into. You get the same sort of thing when the exp tank is full of water.

As a side note here I don't think I'd be cracking that valve between the supply and return. Since the fill valve is very close to the suction side of the pump once the valve is open seems like that's going to respond to the pressure drop that will occur when the pump comes on.

Not likely the feeder is bad. The probelm really started when the pump was changed so the pump is most likely "bad".

GW

not the suction side

The circ is on the return pumping into the boiler, the feeder is seeing higher pressure not lower pressure when the unit is operating. Anyway, I'll remove the ifc thing and see what happens.

Gary

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Steve_35

I'm thinking

If the bypass valve is open the distance between the suction side of the circ and the outlet side of the fill valve through the bypass valve is very short. In such a case it seems possible the fill valve will see low pressure long enough to dump a little water into the system.

BTW, I'm not suggesting this is the problem now. I agree the circ is probably an IFC and that coupled wiht the exp tank location is the likely culprit. I'm just thinking this might be a problem down teh road.

GW

no water in the bucket

I pulled out the IFC gizmo, and went back abour 5 hours later, so far so good. I totally missed the trapped heat, but I have to say I don't usually work on boilers so goofy as this one; next time I'll pay more attention!
Thanks,
Gary

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Mark Hunt

IFC


Gary, if that was the older style Taco IFC with the FC in the volute, you cannot operate them without the FC. They do not have UL approval for operation without the FC.

This is not what was causing the other issues, but it could become an issue with slightly more serious consequences. You may want to change that pump to a non-IFC pump.

Mark H

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chuck_9

pop off

Try isolating auto feed. Is there a coil maybe coil has a leak putting street press. in boiler.

Nron_17

pressure increase

is there an indirect water heater in the system ? make sure the boiler is not filling from the higher side of the domestic storage tank .

Tony_23

That too

Really no need or place for an IFC circ in this application to begin with.

The right tool for the job, I always say

Tony_23

The bypass

MUST be open. This boiler needs to come up to temp quickly to avoid condensation and MAJOR problems later. A bypass is one way to acheive that need.

Ask me how I know

Joe_55

Laars

Check the Laars manual they demand that the bypass be adjusted to ensure 25* to 30* delta T across this boiler

Bill