Share a service call

KCA_2

Hi guys...



  I wanted to share a service call that I went on the other day..  It may help someone down the road...



   The owner of a 6 unit apartment called and told me that two of the units, #3 & #4, were heating up even though the tenant has the t-stat off.  Well I met the gentleman outside and followed him into a crawl space that was 30" high or so...  In the middle of the crawl space was a 6' deep hole that held the boiler...  A 40 year old cast iron monster...  Easily 4' deep by 5' wide and 5' high...  They must have put it in there before they built the building....  You would never be able to replace it...   Or get it out of there...  



The piping comes off of the boiler on the supply side like a octopus.....  Piping going here and there and who knows where.....  The boiler also has a domestic coil in it...  So that makes the piping look that much more ominous... 

In the center of the boiler, on top, there is a 1/2" tapping for a auto air vent....  Well that's where they put the expansion tank....    And about 3' to the left is where the return comes in and ties back to the boiler....  That's where they have a Grundfos UP 43-75....  One heck of a high head circulator...  and it's pumping into the boiler...  A couple of feet prior to the 43-75 are 6 white roger 3 wire zone valves.... 



I looked at the pressure and it was about 30psi and water was running out of the pressure relief valve into the pit that was dug for the boiler...  I tapped on the expansion tank and could tell right away that it way shot...  So I told him that I needed to replace it...   There is about 150 total feet of piping in this apartment...  Not alot of head  for the circulator to overcome... 



I took about 20 minutes to look over the situation and told the owner that I was going to spend his money in order to move the expansion tank from "A" to "B"....  Even though I tried to explain to him what I was doing he wouldn't understand....  (I later sent him one of Dan's articles about pumping away and he says he understands better now)  He actually made me promise him that I would replace the tank at my cost if it didn't work or made things worse...  And I did...  So I relocated the tank..



The circulator was pushing about 10psi....  But since it couldn't push that into the PONPC while the expansion tank was in the boiler, it was creating a much lower pressure on it's suction side...  So I would have +- 18psi in the system before the WR Zone valves and maybe 8psi after the valves...  The circulator was actually sucking water through the valves...  I later found out that all the units were having problems not just #3 & #4....  and they were having problems since 1950....You wouldn't believe all the plumbing company stickers that were on the boiler.... 



I am so happy that I have read some of the books here on Dan's site... 



Today I ran into another situation very similar...  The owners look at you very disbelievingly when you tell them that moving an object 12" or so will fix the problem when a number of other people have charged them a bunch of money repairing that same problem with expensive remedy's sometimes......  Never really fixing it...  Sometimes I do love my job...



:-)  KCA

icesailor

Old Boiler Piping:

That boiler worked when it was installed.

The tapping on the boiler at the top (the 1/2" one) is supplied by the manufacturer for the exclusive use off a compression tank like you have. As far as the circulator, almost ALL of those old boilers were piped with the circulators on the return because with the old inline 3 piece circulators on the supply, the hot water you see on a boiler with a tankless heater will cause boiling around the shaft seal and cause early failure of the seal and bearing assembly. I will bet you a 30 pack that that is not the original pump[. That some unknowing person replaced the first circulator with that high head circulator not ever knowing that what they were doing was wrong.

As far as the heating of the few apartments, the cause is the White Rogers 3 wire zone valves. Water has worked its way up through the shaft O-ring that the motor uses to drive the plug in the valve open and shut. There is a plate on the bottom of the valve that has a spinning disk with electrical connections. The 3 wire valves may close by themselves but the electrical contacts can become contaminated by the minerals in the boiled or evaporated water and cause a short, either keeping the valve open or making the TT terminal always "live" causing the boiler to run on High Limit. There is a "Warp Switch" that closes when power is supplied to it. When the power is removed, it opens, closing the valve and opening the TT terminals.

The relief valve is leaking because the pressure tank is water logged.

If you do what you are suggesting, you may have a poor outcome or at least not the one you expect.

My #1 rule of troubleshooting ANYTHING is, how long has it been there and it must have been working for (fill on how old the system is) years, so what is wrong with it?

The first thing is that improper circulator. Then, zone valves that are partially open.

As far as this old dog is concerned, this is another case where the PONC can be put where the sun isn't shining. It worked without this problem for years until someone replaced the circulator with the wrong one, the pressure tank is water logged, and the zone valves need to replaced. I used White Rogers 3 and 4 wire zone valves 40 years ago. They sucked then. My opinion hasn't changed much. I've used Taco 57* for years. I just switched to the ESP or whatever because of my fear of the O-ring leaking on the shafts. The weakest link.

That's my jaded opinion. Been there, done that.

OBTW, if you take a #60 Extrol tank (a #30 will work, a #60 works better) and connect it to the 1/2" tapping, eliminating the pressure tank, it will work fine. but if the hydro/air tank isn't leaking, it doesn't need to be replaced. Just drained. It may start leaking soon though. I have hung them about every place you can hang them and the systems worked fine. I could show pictures of some I have done but there would irrupt a fire storm of criticism. But they work just fine. The last one was on a W-McL CGM in a Multimillion $ house with a #30 on a cold start boiler with antifreeze. The relief valve was weeping because there wasn't enough room for expansion. I pulled a vacuum on the system, added some nipples, an ell and a Tee and a #60 Extrol. Now, a #30 and a #60. Never a drop of water again. I didn't re-invent the world, and I got paid right away. Problem solved. 

I once had a pressure tank start leaking and in an  emergency, I took a #60 tank and connected it with a washing machine hose to a drain in the system. Chicken Little DID NOT appear. I came back a few days later and permanently connected it.

Mark Eatherton

Chris, I see you've honed your perception skills...

"As far as this old dog is concerned, this is another case where the PONC can be put where the sun isn't shining"



The rules of physics will overcome the powers of perception, EVERY time. Unless you close your eyes to the facts...



ME

Mark Eatherton

Ken...

I think we all agree, the Gfos MUST go. WAY too much head for the application.



In the existing scenario, due to the fact that the pump is pumping towards the PONPC, and the make up is at the pumps inlet, and there is an auto vent right at the pumps inlet, this system has the potential to cause over pressure (PRV "seeing" the negative pressure produced by the high head circulator) and it could, under certain conditions, actually suck air into the system through the auto vent.



It has obviously been bastardized by people who know no better. If it were me, I'd suggest putting the correctly sized circulator on the outlet of the boiler. I'd also put the auto vent, the make up and the expansion tank where the exp. tank is currently connected. I'd also add an isolation ball valve between the boilers return, and the purge cock. This will make it easy to purge. You really don't want to venture down there anymore than necessary do you? If the consumer squawks, then I'd leave him your business card, and walk (crawl?). In these situations, you can do it "right", or do it over and over again at your expense. Attempting to save him money is going to cost YOU money. How much money has he thrown at it to date, with no good results?



I am not a big fan of W/R zone valves. Too many things to go wrong. Throw something simple like a Honeywell V8043 series zone valve in and be done with it.



I pitty the person that is going to have to eventually replace this boiler... Been there, done that (in a younger day) and I refuse to do it any more. Life is too short. So is the crawl space.



ME

KCA_2

Hi Mark

Yeah...  I'm not happy with WR Valves either...  But this guy doesn't want to spend to much..  And the system is working better than it has in a very long time now...

I just posted this because of the application of the pumping away premise...

I thought that someone reading this might remember it next time they come upon such a scenario.... 



I've told him that the circ will need to be smaller at some point ...  Likely when it finally fails...  The ex tank has been moved to position "B"...  and there is no more "Ghost flow"  All is well with the world... 



By the BY....  what did you think of my idea in the Radiant area?  where the guy wants to add a bathroom in radiant and the home is in Baseboard?



 :-)  KCA