Comment on this 4-Boiler Hot Water Setup

zackwatt

I'm doing a walk through on a potential property tomorrow, and it has hot water heat. 4 units, 4 boilers. I've got steam in my house, so i'm pretty familiar with what to look for on steam boilers, but hot water is entirely foreign to me. I know this photo doesn't show a lot, just wondering what jumps out...either good or bad? Thanks!

EBEBRATT-Ed

can't open the photo

Jamie Hall

Got time to make a sketch of the piping arrangements? Particularly with attention to where pumps are, and valves, and the expansion tank -- and comment on whether all four are the same? Or at least photos showing all the piping for a typical installation?

zackwatt

EBEBRATT-Ed said:

can't open the photo

Maybe try this:
https://photos.zillowstatic.com/cc_ft_1536/ISe8fldcin1h6x0000000000.webp

Intplm.

Looks like the #4 boiler is new and not original like the other three ?. Might be a indication that the others will soon need replacing ??

John Mills_5

Isn't #4 original and the other 3 newer?

psb75

One new. Three older. Look at the circulators. The tridicators. See the yellow "Energy Guide"?

STEVEusaPA

Take another picture showing the ceiling. I'd like to see how they are vented.
Is this an original 4 unit building or converted?
What are the green things above each boiler, expansion tank? They look like old water hammer arrestors.
Of course if any replacement is to be done, a proper heat loss so as to not oversize.

zackwatt

Thanks for the replies, this is just off the listing. I am heading over to the property in the next hour. We'll see what we find...

zackwatt

zackwatt

According the Weil Mclain CGA Gold installation manual, the closed expansion tanks this system has should not have automatic air vents on the boiler, as it can case water logging of the expansion tank. I'm assuming the green devises on top of each boiler are just that...automatic air eliminators.

JUGHNE

The green things at each boiler are auto air vents, they have the small tubing to direct any water spurts away from the boiler.

They do not belong on a system that has the compression tank that hangs near the ceiling. They will eventually vent all the air out of the system leaving the comp tank with none and it will become water logged.

The combo relief valve and pressure reducing valves that I see are about the age of the comp tanks. But each boiler has it's own relief valve.
Without a valve between the tank and boiler piping you have to drain the entire system to get water out of the tank.
Does each system have cast iron rads?

zackwatt

Thanks @JUGHNE

At least one has a valve under the tank. I forgot to add this photo:



There are 4 cast iron rads per boiler.

Intplm.

There appears to be no isolation valves on these units as @JUGHNE mensions. This makes for a very tough service call. I would add isolation valves to each boiler so each boiler can be serviced independently without troubling the other living areas.
As it is now, if one boiler needs service all the boilers and units would potentially be affected.

zackwatt

Intplm. said:

As it is now, if one boiler needs service all the boilers and units would potentially be affected.

I must be missing something...as there seems to be 4 of everything, expansion tanks included. I'm not seeing how one boiler service would disrupt the other 3 units.

Henry

The venting is not correct. It is supposed to be Y connections from each boiler. I hope that there is a liner in the chimney.

Henry

Is there a gas hot water tank to the left of the boilers?

zackwatt

Henry said:

Is there a gas hot water tank to the left of the boilers?

Yes, four of those.

JUGHNE

I assume that each heating system is separate with own comp tank, fill valve with cold water supply stop and gas service.
I don't follow how the service of one boiler would affect other units?

True, isolation valves on supply and return for pump changes etc. would greatly simplify that process.
However with only 4 CI rads to drain down and then bleed air out of, although a PITA, it could be worse.

The valves I refer to are to isolate the compression tank from the system and drain any water logged tank while keeping the system full of water. Of course a hose bib must be installed.

Intplm.

zackwatt said:

Intplm. said:

As it is now, if one boiler needs service all the boilers and units would potentially be affected.

I must be missing something...as there seems to be 4 of everything, expansion tanks included. I'm not seeing how one boiler service would disrupt the other 3 units.

On the water side of the boilers. If there is a leak in one of the units, all of the units will have to be drained and restarted because there are no isolation valves installed for each unit , and no isolation valves are installed on each boiler. For example. If there is a leak on the system in unit 2, units 1,3 and 4 will have to be shut down as well as unit 2 because there is no way to isolate the the four systems as shown.

Intplm.

In other words. All of the units would be without heat if only one unit had a leak or similar repair needed.

JUGHNE

What do the 4 units share that water drain down in #2 would require draining of 1-3-4?

STEVEusaPA

That venting is extremely wrong and doesn’t meet code. Can’t believe it works.
I wouldn’t walk into that mechanical room without my personal CO monitor on.

zackwatt

STEVEusaPA said:

That venting is extremely wrong and doesn’t meet code. Can’t believe it works.
I wouldn’t walk into that mechanical room without my personal CO monitor on.

Is there a diagram somewhere of how it should be?

Intplm.

They are all connected as one source. At least from the picture as they are piped. They do not look like they are seperated per unit. At least that's what i can see from the pictures. They do not look like they are seperated from one another. They look like all four boilers are acting as one boiler.

Intplm.

More pictures are needed but the best thing to do is have a expert physically in the basement to verify this.

STEVEusaPA

There’s no diagram, but there is a code book.

JUGHNE

How many electric and gas meters for the building?

Fred

JUGHNE said:

How many electric and gas meters for the building?

I see four electric meters in the corner but I don't see any gas meters.

zackwatt

Fred said:

I see four electric meters in the corner but I don't see any gas meters.

4 Gas meters outside.

Thanks for the comments guys, I actually lost out on my offer on the building. So on to the next one! I need to pick up Dan's book on Hydronics next...

STEVEusaPA

zackwatt said:

Thanks for the comments guys, I actually lost out on my offer on the building. So on to the next one! I need to pick up Dan's book on Hydronics next...

You may have actually won in the long run.

SeanBeans

I would assume that each boiler has its own return and supply piping, and that a leak on #1 wouldn’t share any water pipes with #2 except where the cold water comes in