Boiler Not Heating Water


  #1  
Old 02-16-15, 07:58 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Boiler Not Heating Water

Hi all. This is my first post. If you have any insight to my situation, I would appreciate it.

About two years ago, my Weil-Mclean boiler cracked and was replaced under warranty. After it was replaced, the cast iron pipe coming from the the boiler started to leak. That fall, the company that did the work came out and replaced the leaky connection.

That winter and this winter, when it is really cold outside, the boiler struggles to get the house temp above 63 degrees. This is the case even after running continuously for hours and hours.

The temp gauge reads about 130 and the pressure gauge reads 60psi. While looking at the specs of the unit I noticed thath the max pressure for the unit was 50psi. Is it possible that the replacement part being narrower than the cast iron it replaced be causing the pressure to be too high? Would this cause the boiler to not heat properly? Below are some pictures.










This copper section is the recently installed replacement section.




 

Last edited by NJT; 02-17-15 at 05:43 AM.
  #2  
Old 02-16-15, 08:07 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 71,630
Received 3,323 Likes on 2,984 Posts
Welcome to the forums.

I approved your thread which was held up due to the pictures.

Your pressure is 27 PSI..... use bottom side of the scale for pressure.
130 degrees is low for water temp.

We need a picture of an Aquastat or whatever is controlling the boiler temperatures.
A couple of further away pics would be helpful too.
 
  #3  
Old 02-16-15, 08:18 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Thanks for the quick approval and reply. I have attached a few more pictures.







 

Last edited by NJT; 02-17-15 at 05:42 AM.
  #4  
Old 02-16-15, 08:29 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 71,630
Received 3,323 Likes on 2,984 Posts
Nice pictures. Hang tight..... Trooper, the forum pro, will be stopping by.

Natural gas water heater. Is your heating system one thermostat / one circulator pump ?
 
  #5  
Old 02-16-15, 08:37 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Yes. One pump & one thermostat.
 
  #6  
Old 02-16-15, 08:41 PM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,427
Received 127 Likes on 119 Posts
H,
Take the front cover off the boiler and you'll see a little control with a wheel with numbers on it.
See what that dial is set at. Turn it up to 170 for now and see how it reacts. If you get plenty of heat you can lower it a little to save money as long as you're getting enough heat.
Don't know what you're trying to heat without more info or pics.
You might want to let a little water out of the boiler to drop the pressure to about 18psi for now.
Good Luck,
 
  #7  
Old 02-16-15, 08:43 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Thanks. Heating a single family home. About 2500 square feet.
 
  #8  
Old 02-16-15, 08:51 PM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,427
Received 127 Likes on 119 Posts
My guess is you have radiators. Your 1" main coming off the boiler looks very small to deliver enough hot water to those black pipes(1 1/2"?). Are the units getting very hot.
 
  #9  
Old 02-16-15, 08:54 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
I do have radiators. They are cast iron and original to the house. about 90 years old. They are only warm-ish. Not very hot.
 
  #10  
Old 02-16-15, 09:00 PM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,427
Received 127 Likes on 119 Posts
Did you find the control with the wheel? Those black pipes is how I figured you had rads. They're trying to feed that whole house and all those rads with a 1" pipe coming off the boiler. Can't see that happening.
Let's see what the temp is for now.
 
  #11  
Old 02-16-15, 09:17 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Temp is set to 140. So...setting to 170 will not be a problem?
 
  #12  
Old 02-16-15, 09:24 PM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,427
Received 127 Likes on 119 Posts
No, it should be up around there anyway for now, but I think you have bigger problems. You have got 2.6 gals. of water in that boiler and you're trying to reach that whole house at once.
That 1" pipe trying to feed all those 1 1/2 or 2" black pipe is like having a 1/2" cold water feed trying to feed all your faucets at the same time. You do not have enough volume.
At least the higher temp will heat the water better. I just don't think it will keep up.
 
  #13  
Old 02-16-15, 09:38 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Couple of more pictures of the set up.




 

Last edited by NJT; 02-17-15 at 05:41 AM.
  #14  
Old 02-16-15, 09:55 PM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,427
Received 127 Likes on 119 Posts
H,
Please don't take offence but that piping job is awful. They should know better than to do anything like that.
There is no way you'll get enough heat into those rads to heat the house.
If this is a recent job I would call them back and explain to them what you're going through.
I looked that boiler and it only comes with 1" tappings. Weil McLain is a good boiler but in your case you need one with bigger tappings.
 
  #15  
Old 02-16-15, 10:04 PM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,427
Received 127 Likes on 119 Posts
H,
Just an observation.
They have bx electrical cable ties rapped to a steel pipe. They apparently have never heard of electrolisys?.
Two dissimilar metals. You might want to cut the plastic or put pipe covering if you want to strap it back again.
 
  #16  
Old 02-17-15, 05:17 AM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Thanks for the feedback. No offense taken! This was the set up when I bought the house 5 years ago. Given that the boiler is brand new and I have no real budget, is there anything that could be done to help improve the situation?

BTW, moving the temp up to 170 has improved things a good bit.
 
  #17  
Old 02-17-15, 06:17 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
Given that the boiler is brand new and I have no real budget, is there anything that could be done to help improve the situation?
I think the only thing that will correct that situation is a proper re-piping.

I'm quite sure that the install manual has specific statements regarding 'boiler protection' in regard to systems like yours with high water volume.

I don't know if you have any recourse with the installers, but it's worth a shot.
 
  #18  
Old 02-17-15, 06:34 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
Is this the same model boiler as the old one?

How long did the old one last?

Do you have the boiler manual?
 
  #19  
Old 02-17-15, 07:11 AM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
The model is the same and I do have the manual. The company that replaced the boiler did the original install about 12 years ago. The original boiler lasted 7 years and then cracked. It was leaking and they replaced it under warranty. The rest of the unit was not replaced. I am at work and don't have the manual with me.
 
  #20  
Old 02-17-15, 03:24 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
I noticed something else in your pictures that bothers me a bit.

That insulation blanket on the water heater...

It looks as if it's installed such that it is blocking the combustion air intake. If it is, that's a dangerous situation that needs remedied.
 
  #21  
Old 02-17-15, 04:06 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Thanks. I will remove the blanket. I did some reading in the warranty and install guide. You are correct that improper installation voids the warranty. I guess I am lucky they replaced the cracked boiler, as the warranty only pertains to the original purchaser. I am not the original owner. It also looks as if the correct boiler model was/is the CGa 8, not the CGa 5. The 5 is for 1" systems and the 8 is for 1 -1/2 systems. Is there anyway to retro fit the existing boiler and re-pipe to be correct?
 
  #22  
Old 02-17-15, 04:21 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
You don't need to remove completely if you think it helps... just make sure it doesn't cover the combustion air intakes, the controls, or any relief valve or drain valves. Does it extend up over the top? It should not. Anything gets too close to that vent pipe it poses a fire hazard.

You could probably trim the bottom up a way and retape it.

I don't know they do a heckuva lotta good anyway.

No, my goodness, you don't want to put an 8 section boiler in there... that's WAY too many BTU! If piped properly the size of the boiler is fine, maybe even the 5 section is too large in terms of BTU output.

It's not the size of the pipe, it's all in the installation.
 
  #23  
Old 02-17-15, 04:32 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
So the next question is what would re-piping cost (approx)? Also, I have some experience building stuff/mechanical stuff. Could I do this job myself without causing undue harm to myself and my family? This would be in the summer when no heat was needed.
 
  #24  
Old 02-18-15, 09:57 AM
H
Member
Join Date: Dec 2013
Location: USA
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
Hilsen,

If you don't have a system/Boiler bypass then why is your boiler riser going into the branch of a tee?
Can we see the piping and valves on the LEFT side of the boiler?
I think the insulation on the water heater is blocking some of the view.
 
  #25  
Old 02-18-15, 04:30 PM
H
Member
Thread Starter
Join Date: Feb 2015
Location: United States
Posts: 12
Likes: 0
Received 0 Likes on 0 Posts
Here are some more pictures:













 

Last edited by NJT; 02-18-15 at 05:24 PM.
  #26  
Old 02-18-15, 04:50 PM
G
Member
Join Date: Oct 2008
Location: USA
Posts: 3,062
Received 24 Likes on 23 Posts
So the next question is what would re-piping cost (approx)? Also, I have some experience building stuff/mechanical stuff. Could I do this job myself without causing undue harm to myself and my family?
Do you have any experience installing and soldering piping? If not, this is not a starter job. (It seems to have been a starter job by the guy who did it originally.)

I'm not a plumbing contractor, but my guess would be an experienced plumber and a helper for two days. But let's say three days to be safe and to allow for additional issues not shown in your pix. That is 8x2x3 = 48 manhours. What does the customer expect to pay per hour in your area? If it's, say, $60, that would be nearly $3,000, plus materials.
 
  #27  
Old 02-18-15, 05:28 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
why is your boiler riser going into the branch of a tee?
I'm not sure what you're seeing there Heatworm?

There are two supplies, and two returns, joined together... two on the right, supply and return, two on the left, supply and return.

(It seems to have been a starter job by the guy who did it originally.)
Ain't that the truth! Look at the way he's got the supply from the boiler tied in a knot... jeesh...

Hilsen, a big part of the problem is that you're going to have a very hard time finding someone qualified to design and execute...
 
  #28  
Old 02-18-15, 05:31 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
THERE IS A BYPASS!

A BOILER bypass to be exact, because it is on the BOILER side of the circ pump.



maybe this is what heatworm was seeing!

That pipe on the left with the handle removed from the valve and hanging on the wire.

That's the bypass pipe.

Comes off a TEE at the supply riser, to the left, back, and down to the return.

Hilsen, can you get a close up shot of the valve where the handle is removed so we can see what position that valve is in? Unscrew the nut, (don't lose it!)... we need to see the 'flats' on the shaft.
 
  #29  
Old 02-18-15, 05:42 PM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,427
Received 127 Likes on 119 Posts
H,
Your latest pics are very enlightening and actually in my opinion not piped as bad as I first thought.
You do in fact have a bypass to temper the water which is a good thing. It's the return pipe on the left. The pipe with the ball valve. That is actually adjustable to let in more or less supply water to warm up the colder water coming back preventing thermal shock to the boiler preventing cracking again.
The worse thing I see is instead of using all 1" pipe to your 2 supply lines they reduced to 3/4" and used a tee instead of staying 1" after the ball valve after the pump and feeding each line independently.
Initially I thought you had 3 supply lines but you have 2.. He also came back into the returns with 3/4" into the 1" but honestly I don't think that is such a big issue.
They loved using tees for some reason. Even your bypass line comes off a tee.
I think if they would have stayed 1" after the pump and fed each supply and bypass independently you would get much better results.
This is just what I would do. Everyone has there own way of doing things.
The bottom line is with minor repiping you have a keeper.
By the way you said you're getting better results with the higher temp. You still can raise another 10 or so safely if you need more heat for this cold weather. Just keep an eye on the pressure if you didn't lower it at all.
Relief valve will go off at 30 psi.
 
  #30  
Old 02-21-15, 04:34 PM
H
Member
Join Date: Dec 2013
Location: USA
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
1) Pump inlet is not piped properly.

TEH 1275A Equipment Room Piping Practice [pdf]



2) Delta T should be 60+ F
PP 22,23 GOLD CGa Gas-Fired Water Boiler Boiler Manual
BOILER-bypass piping method

This piping method (Figure 15 or 16, page 23) is called
a boiler-bypass because part of the circulator flow is
bypassed around the boiler (through valve 7a). This
method reduces the flow rate throughout the boiler, in
order to raise the average water temperature in the boiler
enough to prevent flue gas condensation. Boiler-bypass
piping is effective for some boilers -- including the CGa
provided the flow rates are adjusted according to the
instructions following."
 
  #31  
Old 02-21-15, 04:52 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
1) Pump inlet is not piped properly.
Perhaps not ideal, but it will still work, and is not the source of the problem. There are millions of these pumps out there that are piped worse than this.

2) Delta T should be 60+ F
Huh? Is that a typo? Please explain further what you mean.
 
  #32  
Old 02-21-15, 08:43 PM
rbeck's Avatar
Member
Join Date: Jul 2007
Location: United States
Posts: 2,675
Likes: 0
Received 57 Likes on 47 Posts
He needs a valve either on the return or supply below the bypass to adjust the flow through the boiler and increase the flow through the bypass and reduce flow through the boiler. Someone commented they saw somewhere the boiler had 1" tappings. If that is the case and the boiler is 140k they are designing on a 40f delta T. I cannot believe the tappings are not 1-1/4".
If the boiler is 140k it is twice the size it needs to be for the home so the boiler is plenty big.
 
  #33  
Old 02-21-15, 09:05 PM
H
Member
Join Date: Dec 2013
Location: USA
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
If you accept W-M claim above for CGa boiler, then to protect the boiler form thermal shock limit the flow of water. The grater the temperature rise (Delta T) the less thermal stress.

To quote the Manual:
CGaBoilerManual [pdf]

Page 22, GOLD CGa Gas-Fired Water Boiler Boiler Manual
Valve adjustment
. . .A minimum 60F temperature rise
through the boiler assures a low enough flow rate
and high enough average temperature to prevent
condensation even with low system return water
temperature. . . .
The system is missing valve 7b but the high head loss of the return and supply header may make that moot.
Missing a return temp gauge too.
 
  #34  
Old 02-21-15, 09:07 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
The tappings on all the CGa boiler sizes are 1-1/4". This is from the manual in the notes under Table 3 on page 16. It also says in the notes that the supply and return connections, and the tees supplied for the return/drain, and the supply/gauge are all 1-1/4". They supply two different size circulator flanges with the boiler. One flange is 1-1/4, the other flange is the recommended supply and return pipe size based on the table.

Weird thing is that Table 3 is titled: Water Pipe Size (based on 20F rise)

And then, for the 3,4,5 section boilers they recommend using 1" for the supply and return piping.

I don't get it...
 
  #35  
Old 02-21-15, 09:10 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
The grater the temperature rise (Delta T) the less thermal stress.
Huh?

You mean to say that there is less thermal stress on a boiler with a 60F rise than there is on a boiler with a 20F rise?

I don't think so ....... That's totally against the laws of physics.

And it's not 'thermal shock' they are protecting the boiler from anyway, it's CONDENSATION.

What they are TRYING to say (unsuccessfully in my opinion) is that the return water can be as low as 120F AS LONG AS the flow through the boiler is limited enough that the SUPPLY reaches 180F.

This would give an AVERAGE temperature in the boiler of 150F which should protect it from condensation.
 
  #36  
Old 02-21-15, 09:20 PM
H
Member
Join Date: Dec 2013
Location: USA
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
CGa-5 AGA input 140,000, output into water DOE 117,000BTUh.
A delta T of 20 degrees requires a flow rate of 117,000/(20 F x 500) =11.7GPM
and with a delta T of 60 or more the flow is less than 4 GPM,
so no need for large tappings.
W-M recommends primary/secondary.
 
  #37  
Old 02-21-15, 09:34 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
Yes, understood, but the real question is:


You mean to say that there is less thermal stress on a boiler with a 60F rise than there is on a boiler with a 20F rise?
What's your answer?

A delta T of 20 degrees requires a flow rate of 117,000/(20 F x 500) =11.7GPM
And since they say in Table 3 that they recommend 1" pipe for a 20F rise, that would seem to imply that W-M thinks it's OK to run 1" pipe at 12 GPM... right?

You don't see anything wrong with that picture?

If you accept W-M claim
That says it in a nutshell... I don't accept W-M ...
 

Last edited by NJT; 02-21-15 at 09:56 PM.
  #38  
Old 02-21-15, 09:54 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,538
Likes: 0
Received 8 Likes on 6 Posts
Hilsen, how come no replies? This is YOUR thread, don't be shy. We can't help you if you don't join in the converstaion and answer questions!

Hilsen, can you get a close up shot of the valve where the handle is removed so we can see what position that valve is in? Unscrew the nut, (don't lose it!)... we need to see the 'flats' on the shaft.
 
  #39  
Old 02-22-15, 12:32 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 71,630
Received 3,323 Likes on 2,984 Posts
Looks to be about 75% open......

Name:  valve (2).jpg
Views: 287
Size:  28.7 KB
 
  #40  
Old 02-22-15, 04:07 PM
H
Member
Join Date: Dec 2013
Location: USA
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
You mean to say that there is less thermal stress on a boiler with a 60F rise than there is on a boiler with a 20F rise?
I don't have any data to quantitatively say that. I did mean to say that the stress would fall within a acceptable range qualitatively, for systems that are not rapidly chilled. Rapid chilling would be damaging[SUP](1, 2, 3)[/SUP] but when would that happen with this system?

Average boiler temperature is more important.

"Jason" quoting Gil Carlson forum.heatinghelp.com/discussion/150114/boiler-bypass
...
To quote Gil Carlson who invented the boiler bypass. Thermal stress and flue gas condensation is a result of extremely cold water entering the boiler or cool water at a high flow rate" The return temperature is not as important as the flow. We should be trying to get the average water temperature of the boiler above condensing temp. When the boilers switched to low water volume the bypass switched to a boiler bypass. System bypasses are for higher water volume. . . .


"Laars Heating Systems 0005 Document 5002E
A Discussion of Water Heater Design"
------------------------------
"An Analysis of the Advantages and Disadvantages
of the Wet Section Design in Four Types of Boilers"
. . .
V. The Subject of Heat Transfer in a Boiler

In the process of transferring heat from the hot
gas to the water in a boiler, two major barriers are
encountered. They are (a) the gas film on the fireside,
and (b) the liquid film on the wet side (see Fig. 3).
On the wet side water tends to form a stagnant
liquid film which clings to the metal surface. This acts
as an insulator and greatly impedes the flow of heat
from the metal to the water. If the water is forced to
move at high velocity this stagnant film will be scoured
away and the flow of heat to the water will be greatly
speeded[sic] up. ...
1)Modern Hydronics 2010 may/june [pdf]
pp 42,43 [pp 22,23 pdf] The Facts About Sudden Thermal Changes

2) Boiler-Bypass All About Cast Iron boiler Protection
 

Last edited by NJT; 02-23-15 at 04:23 PM.
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: