Boiler problems that HVAC company can’t solve

bewilderedboilerboy

Hi all—I bought a house this past year with a 4-year old boiler and a hydronic heating system with water radiators. I’ve had a bunch of trouble with it. There’s always a ton of air in it, so much that I bleed the radiators two or three times a day and there’s still a lot of air (three ground floor radiators and one basement radiator can be bled for maybe 10 seconds each 3 times a day—the upper floor radiators never have much air, which is mysterious too). If I don’t bleed the radiators the pressure shoots up to almost 30 psi, then after I bleed them they drop down to about 20. The boiler company has replaced the expansion tank, and then the heat exchanger cracked and they replaced the whole boiler even though it was less than 5 years old.

Now this morning I’ve found that the boiler is leaking again! I’m in for $ at this point on a boiler I thought I wouldn’t have to touch for 20 years, and the company has no idea what’s wrong, and now it looks like it’s broken again. Does anybody have any idea what might be wrong, or how there’s so much air in the system? Thanks so much in advance, and happy to provide photos or more info if helpful.

PC7060

Sounds like your pressure tank is faulty or closed off.  Please post photos of the boiler along with the piping in the immediate area. Look for a tank similar in size to a 20 pound propane tank and provide pictures of that too.  

Where is the boiler leaking? Provide photos of that if you can.

if you pressures are getting up to 30PSI I’d expect the pressure relief valve to go trip which will dump water onto floor.  

HVACNUT

The block should be under warranty if that's what's leaking. 
The company should stand by their work. 
You're bleeding rads only to relieve the pressure?
Is there an indirect water heater?
Pics please. 

bewilderedboilerboy

Thanks for the response! The expansion tank is definitely open and is also brand new.

The boiler is leaking from the bottom, water is gathering in the pan under the heat exchanger (also brand new) and then leaking out onto the ground. It looks to me like the heat exchanger is cracked again, which would be outrageous.

bewilderedboilerboy

HVACNUT said:

The block should be under warranty if that's what's leaking. 
The company should stand by their work. 
You're bleeding rads only to relieve the pressure?
Is there an indirect water heater?
Pics please. 

Hi HVACNUT, thanks for your thoughts! Yes I'm only bleeding the radiators. Perhaps I should also try to bleed out water? The guy from the HVAC company who came by said I shouldn't try to bleed out water because we want positive pressure to keep more air from getting in, he felt pressure in the low-20s was fine (and he suggested we add another Spirovent to prevent it from jumping up toward 30 psi but said in the meantime I should just continue bleeding the radiators 3 times a day).

STEAM DOCTOR

All of that bleeding may have introduced lots and lots of fresh water into the boiler. But do confirm that it's actually the boiler that's leaking. 

bewilderedboilerboy

STEAM DOCTOR said:

All of that bleeding may have introduced lots and lots of fresh water into the boiler. But do confirm that it's actually the boiler that's leaking. 

I don't have an autofill, although I did fill manually once after my mom suggested I drain a couple buckets of water out to try to get air out (didn't work). I really really hope it's not the boiler that's leaking, it was installed just a few weeks ago.

Ironman

Is this a system that been converted from steam to hot water?

 The pics that you’ve posted don’t show enough of the piping around the boiler. Can you take some from farther back that would show more?

bewilderedboilerboy

Ironman said:

Is this a system that been converted from steam to hot water?

 The pics that you’ve posted don’t show enough of the piping around the boiler. Can you take some from farther back that would show more?

The HVAC company repairman said that it wasn't an old steam system and was always hot water. Here are some more pictures, thanks!

EBEBRATT-Ed

@bewilderedboilerboy
.

Post your location and check "find a contractor" on this site. You need someone that knows what they are doing

Sounds like your present company does not have a clue

bewilderedboilerboy

EBEBRATT-Ed said:

@bewilderedboilerboy
.

Post your location and check "find a contractor" on this site. You need someone that knows what they are doing

Sounds like your present company does not have a clue

I'm starting to agree . . . unfortunately I tried the "find a contractor" tool and there was nobody within 100 miles. I'm in the Twin Cities and I use Binder Heating, which is supposed to be one of the best (and they're very nice people, just not great at solving my problems!).

george_42

I do not see a relief valve on boiler

pecmsg

All that black piping in the back, is that part of the system? If yes that's from an old gravity system.

bewilderedboilerboy

george_42 said:

I do not see a relief valve on boiler

Ah sorry, it's not visible because of the camera angle. It's there, and set to blow at 32 psi.

bewilderedboilerboy

pecmsg said:

All that black piping in the back, is that part of the system? If yes that's from an old gravity system.

Yessir--my boiler company said that too, that it's from an old gravity hydronic system that was converted to pumps. Is that something to be concerned about?

DanHolohan

Do you guys see a bypass to blend hot supply water into cold return water? Could be thermal shock going on.

Also, I wonder if that Extrol tank is large enough for that amount of water, and if it's properly charged with air.

EBEBRATT-Ed

I honestly can't tell what is happening there

JUGHNE

Gravity flow sized pipes and 2 floors of CI radiators might contain enough water to have expansion tank double that size.

Rich_49

bewilderedboilerboy said:

EBEBRATT-Ed said:

@bewilderedboilerboy
.

Post your location and check "find a contractor" on this site. You need someone that knows what they are doing

Sounds like your present company does not have a clue

I'm starting to agree . . . unfortunately I tried the "find a contractor" tool and there was nobody within 100 miles. I'm in the Twin Cities and I use Binder Heating, which is supposed to be one of the best (and they're very nice people, just not great at solving my problems!).

Try Badger Boiler in Prior Lake or call Aune plumbing and heating out of Zimmerman . I think a guy Ground Up ( from HH site ) is possibly near you also

bewilderedboilerboy

DanHolohan said:

Do you guys see a bypass to blend hot supply water into cold return water? Could be thermal shock going on.

Also, I wonder if that Extrol tank is large enough for that amount of water, and if it's properly charged with air.

A boiler repair guy is here right now and this is exactly what he thinks is going on! There was no bypass and the water in the return comes back pretty cold (it's -4 F right now), the return water is 90 F or less.

It turned out that the heat exchanger cracked AGAIN (last one lasted 4 years, this one lasted less than 4 weeks), the company thinks we need to replace the boiler and install a bypass along with a more strategically placed spirovent, and do a little repiping too.

The Extrol tank is the #90--it actually used to be #30 until it was replaced a couple months ago. Hopefully it's big enough now!

WMno57

bewilderedboilerboy said:

Yessir--my boiler company said that too, that it's from an old gravity hydronic system that was converted to pumps. Is that something to be concerned about?

I have an old gravity system that had a pump added later. It works great. As others have stated, the expansion tank needs to be larger than what would normally be installed for a given number of radiators. This is to account for the larger volume of water in the pipes. Also the pressure in the tank needs to be set correctly.
How many radiators, zones, and pumps in your system?

DanHolohan

I'm glad the repair guy is there. Note that the bypass has to move hot boiler water into the return water to bring up its temperature before it hits the hot iron.

Some bypasses allow return water to bypass the boiler and join the hot supply. That's not what you need here.

As to the size of the Extrol. It sounds like someone is guessing at it. Has anyone looked at the Amtrol tank-sizing instructions?

Zman

I think that the lack of a real air separator and circulator pumping toward the expansion tank are your biggest problems in regard to the air.

bewilderedboilerboy

WMno57 said:

bewilderedboilerboy said:

Yessir--my boiler company said that too, that it's from an old gravity hydronic system that was converted to pumps. Is that something to be concerned about?

I have an old gravity system that had a pump added later. It works great. As others have stated, the expansion tank needs to be larger than what would normally be installed for a given number of radiators. This is to account for the larger volume of water in the pipes. Also the pressure in the tank needs to be set correctly.
How many radiators, zones, and pumps in your system?

Hmm hmm, I'm pretty sure that nobody has adjusted my tank pressure, it's just the same as out of the box--think it's pre-charged to 12 psi but presumably as the bladder is pushed down it gets higher.

I have 4 zones and 14 radiators in my system. Most of the house is on one zone (9 radiators), I have 2 baseboard radiators on one zone, one radiant bathroom floor on one zone, and 2 basement radiators on one zone.

bewilderedboilerboy

DanHolohan said:

I'm glad the repair guy is there. Note that the bypass has to move hot boiler water into the return water to bring up its temperature before it hits the hot iron.

Some bypasses allow return water to bypass the boiler and join the hot supply. That's not what you need here.

As to the size of the Extrol. It sounds like someone is guessing at it. Has anyone looked at the Amtrol tank-sizing instructions?

Gotcha--hopefully the joining hot and return water is what they have in mind but I'll check!

I hoooope somebody has looked at the instructions at some point, but they certainly haven't done it in front of me. It's an old system joined with a new one so I wonder if they're just guessing at the water volume.

bewilderedboilerboy

Zman said:

I think that the lack of a real air separator and circulator pumping toward the expansion tank are your biggest problems in regard to the air.

Yeah I'm told they're going to replace the boiler, add a bypass, and also add an air scoop on the supply line to the main part of the house. Hopefully that'll solve the issue. On the expansion tank, the repair guy alluded to it being in the wrong spot while talking to his boss but I didn't understand what he meant. Are you saying the expansion tank is in the wrong location? That would be useful because I could ask them to take care of that when they do the work. Thanks!

DanHolohan

You should pump away from the tank. 

bewilderedboilerboy

DanHolohan said:

You should pump away from the tank. 

Ohh I'll be sure to bring that up too, thanks!

TomS

Do yourself and your contractor a favor and have them read one of Dan Holohan's books. Click on "store" to see what is available.

STEAM DOCTOR

Your mentioned that you were bleeding a lot, but didn't have an auto feed. Any chance the boiler dry fired? 

bewilderedboilerboy

TomS said:

Do yourself and your contractor a favor and have them read one of Dan Holohan's books. Click on "store" to see what is available.

I might buy one of these myself, looks fun--thanks for the tip!

bewilderedboilerboy

STEAM DOCTOR said:

Your mentioned that you were bleeding a lot, but didn't have an auto feed. Any chance the boiler dry fired? 

I don't think so--to clarify I bled out a lot of air but there still seems to be plenty of water in the system. (That said there's plenty of air too so maybe that's a kind of dry firing).

catastrophy

So they replaced the old expansion tank and then the old boiler cracked and they replaced it with a new boiler that has since cracked. What was wrong with the old expansion tank? And what is the differences between the old and new expansion tanks?

rick in Alaska

Also, when they change the expansion tank out, have then put in a drain valve between the ball valve and the tank.
Rick

tim smith

Has multiple zones it looks like, not piped primary/secondary.  Expansion tank looks like may not be in correct location. My guess is thermal shock on boiler heat x if in fact its cracked.  Just some thoughts from photos but can't be conclusive from limited pictures. Verify pipe arrangement with boiler manual piping diagrams for multiple zones. Weil Mclain does exclude prim/sec piping if return temps above 130 in their manual for this type of boiler it looks like.

WMno57

catastrophy said:

So they replaced the old expansion tank and then the old boiler cracked and they replaced it with a new boiler that has since cracked. What was wrong with the old expansion tank? And what is the differences between the old and new expansion tanks?

The expansion tank could be a red herring. I'm thinking the two boiler failures 4 years apart were due to thermal stress. Caused by either incorrect bypass piping or dry firing.

JUGHNE

IIUC, they already changed from a 30 tank to a 90.

This system would have had either a ceiling hanging compression tank, maybe 16" in diameter and 4-5' long. Perhaps connected to the old boiler.

Or an open top tank perhaps on top floor or even attic. This would have been connected to the piping system possibly anywhere. It may still be in place.

A real grasping of straws is that one of these tanks is still connected to the system somehow.
Almost an impossibility, but stranger things have happened.

IMO, worth a little research.


Do you have any other air vents other than the one shown in the picture?

Maybe a small one on the bathroom floor radiant heating?

It seems air is getting sucked into the system somewhere.

bewilderedboilerboy

catastrophy said:

So they replaced the old expansion tank and then the old boiler cracked and they replaced it with a new boiler that has since cracked. What was wrong with the old expansion tank? And what is the differences between the old and new expansion tanks?

New expansion tank is way bigger (3 times bigger--Amtrol #90 vs #30). However I think this may be a symptom of the excessive air, the problem was that when I got the pressure to 12 psi cold and didn't bleed regularly (before I accepted my new life as an amateur boiler tech), it would get up to 60 psi when hot. The relief valve eventually blew but I think in the meantime the tank was wrecked.

bewilderedboilerboy

rick in Alaska said:

Also, when they change the expansion tank out, have then put in a drain valve between the ball valve and the tank.
Rick

Thanks--I assumed they had done this when I asked them to put the shutoff in but they didn't!! I'll ask.

bewilderedboilerboy

tim smith said:

Has multiple zones it looks like, not piped primary/secondary.  Expansion tank looks like may not be in correct location. My guess is thermal shock on boiler heat x if in fact its cracked.  Just some thoughts from photos but can't be conclusive from limited pictures. Verify pipe arrangement with boiler manual piping diagrams for multiple zones. Weil Mclain does exclude prim/sec piping if return temps above 130 in their manual for this type of boiler it looks like.

tim smith said:

Has multiple zones it looks like, not piped primary/secondary.  Expansion tank looks like may not be in correct location. My guess is thermal shock on boiler heat x if in fact its cracked.  Just some thoughts from photos but can't be conclusive from limited pictures. Verify pipe arrangement with boiler manual piping diagrams for multiple zones. Weil Mclain does exclude prim/sec piping if return temps above 130 in their manual for this type of boiler it looks like.

Interesting interesting, can I ask what you mean about excluding prim/sec piping? Looks like return temps at the boiler are more like 90 than 130. That's why the boiler tech who came out agreed with you that it's probably thermal shock and they're going to install a bypass.

Matt_67

You should also make sure the pex on the infloor loop has an oxygen barrier.