Critique this boiler / hot water heater setup

Old 11-07-12, 08:01 AM
Thread Starter
Join Date: Nov 2012
Location: United States
Posts: 49
Received 0 Votes on 0 Posts
Critique this boiler / hot water heater setup


I just joined the forums. I just had some work done in my house, replacing the old boiler and water heater with new systems, and having the house set back to having 3 heating zones. It used to have three, but at some point the previous owner removed the zone valves and tied all 3 zones together. Now, we're back to 3 zones, or at least we will be once the new thermostat is installed. For now, zones 2 and 3 are tied together.

The entire house has 1/2" hot water baseboard heating.

Since putting this in, we've been getting very little heat on Zone 1. The supply side is hot, the return side is cold, and the baseboards on Zone 1 (2 floors above) are slightly warm but not very hot. And we've been getting a loud banging in one of the bedrooms on Zone 1. The banging is a single bang that repeats every few minutes.

I expect the banging is from air in the system, or maybe from copper piping that is not properly anchored somewhere. There is an automatic air ventor above the boiler, which I would expect would remove all of the excess air.

Was this system installed well? Are the valves on the right way? Is the circulator pump (blank box to the left of the boiler?) looking good? It hums very loudly while the unit is on, and is incredibly hot to the touch.

And it looks like I've already got a lot of cracking in the mud where the vent pipes feed into the chimney.

When looking at the boiler, return (to boiler) is on the left and supply (from boiler) is on the right.

The boiler is a Weil McLain CGa gas boiler. The water heater is a gas-fired Rheem 40 gallon unit.

Larger images available at: boiler_waterheater - Imgur

Attached Images           
Old 11-07-12, 08:25 AM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,159
Received 69 Votes on 61 Posts
When was this installed?

I would call the installer back. Here in NJ any installer I know usually gives a 1 year warranty on everything.

With that said there are several things that can be checked and additionally probably needs to be re purged.

Check the pump and make sure its installed in the correct direction. Arrow on the pump body should point down.

The air elimination device...Not sure if that one is directional. Check for an arrow on the body. Give us the make of that unit.

What does the temp and pressure gauge read?

They should come a touch up the cement at the flue.

I see a valve off in the cieling there with a yellow handle....

I really do not see any purge station. I do see the large yellow handle valve just above the pump may have a hose bib attachment. That will work only if its oriented correctly and that is indeed what I see.

Hope this helps.
Old 11-07-12, 09:25 AM
Join Date: Apr 2011
Location: nj
Posts: 575
Received 0 Votes on 0 Posts
Its so so i would say. Somewhat neat but a lot of crucial elements were left out in my mind. As lawrosa said, no purge station which is a huge problem in my mind, especially on a new install. I typically like to install my supply pumps after the air elimination and put my zone valves on the return side with shut off valves (ball type) and purge tees. Im also a fan of a ball valve and drain designated for the expansion tank for servicing. Check you zone valves and make sure they are installed in the correct direction, because they bang when they close if not installed in the correct way.
Old 11-07-12, 06:50 PM
rbeck's Avatar
Join Date: Jul 2007
Posts: 2,503
Received 9 Votes on 7 Posts
There is a purge valve just above the pump and ball valves on each return line. I saw better on the larger pic's following the ling in original post.
I would mostly agree with RDSTEAM. The pump manufacturers suggested putting the pumps on the supply side of the boiler pumping away from the expansion tank connection to eliminate air better. This way in the fifties.
I would keep the zone valves on the supply for two reasons.
1. Keeps all serviceable parts in the same area which makes for easier isolation.
2. If you may experience a gravity thermal circulation problem it would be on the hottest side of the boiler. Zone valve on the supply side will make sure this does not happen.
In this installation you can use 3 valves above the zone valves and and a ball valve between the expansion tank connection and elbow at the top of the boiler standpipe, you can isolate everything for servicing, losing very little water to gain access, and not requiring to purge after servicing. The less water you add to the boiler in it's lifetime the better and increased life of the boiler.
Instead of an elbow at the top of that standpipe use a tee. The end of the tee can be a purge valve.
I also never end the manifold with an elbow, I always use a tee. In the tee I install a boiler drain. This allows a place to remove the water for servicing of all the parts with very little water loss. The second advantage to this is a place to add another zone without removing and elbow and installing a tee.
Old 11-08-12, 10:24 AM
Thread Starter
Join Date: Nov 2012
Location: United States
Posts: 49
Received 0 Votes on 0 Posts
Thank you all for the feedback. I forgot to mention that we plan to install a water softener soon, and had the boiler/water-heater installer add some extra tubing to allow us to do that easily. Our plan is to put the softener to the left of the boiler, using the long piece of vertical pipe connected to the backflow preventer. Once we do that, the yellow valve near the ceiling (above the water heater) becomes the softener bypass. I'm sorry for not putting that in the origial post.

Unfortunately, with that setup, while the hot water heater will get softened water, the boiler will be tied to the untreated (hard) water. The installer doesn't seem convinced the boiler is better of with soft water, but based on my research (internet, and calling Weil McLain), it seems like a smart idea to feed the boiler with soft water. While ideally the boiler will be refilled infrequently, every little bit helps.

Q: When was this installed?
A: 2 weeks ago. The installer is coming back to install a new thermostat. I still owe him final payment, so I'm confident he'll be back to finish the job. I am definitely going to ask him all these questions. I came here for some background, so I could understand his answers better.

I had trouble finding an arrow on the pump (black box on the return side, right?), but I'll keep looking. The spot on the pump where the eletric comes in buzzes loudly and gets crazy hot, so I've been reluctant to poke around there.

Ditto for the air elimnation device. I couldn't find an arrow, but I saw it's a Taco 4900 Series Air Separator 1 1/4", model 49-125 T-2. While I didn't see an arrow, my installation matches the diagram in this PDF, so I think it's on right.

Q: What does the temp and pressure gauge read?
The boiler has an analog temperature/pressure gauge which listed 115 degrees at 24 PSI. It wasn't currently running, but had been recently running. It also has an LCD temperature gague inside the metal case, which listed 120 degrees. I've seen the analog gauge read 28 PSI when the boiler was at full temoperature (180 degrees). Is that within range?

Regarding the hose bib / purge station.. There is a valve and faucet both above the pump (tiny 90-degree yellow handle) and below it (blue circular handle), as @rbeck said. I'm not sure if these are the hose bib / purge station you mentioned.

@Groucho Marx
Once of the biggest issues I found online was to whether the pump should go on the supply or return side, before or after the expansion tank. I wish I'd known beforehand to ask that it be put on the supply side after the expansion tank.

I looked at the zone valves (metal boxes on the supply side), and they have an arrow pointing UP, so they are installed in the right direction.

Thank you everyone for your comments.

Old 12-11-13, 11:48 AM
Thread Starter
Join Date: Nov 2012
Location: United States
Posts: 49
Received 0 Votes on 0 Posts
To give you all a follow up on this system...

Once December/January came, we were getting a lot of loud banging from the upstairs zone from the heat. I assumed the problem was that the older existing copper tubing in the walls/floor had a clog somewhere, since the area has hard water and the previous owner did not have a softener. So I spent a day cutting the zone loop at different points (between fin sections, in the garage ceiling, just as it left the unfinished basement) and couldn't find any areas of slow flow. We eventually narrowed it down to there being some clog in the new tubing the installer put in.

He came back, removed the zone valve, and found a marble-sized chunk of solder stuck in the zone valve. He blamed his helper and immediately replaced it with a new valve, solving that problem.

Though the thing that seems wierd to me now is that the burner only stays on for about 60 to 90 seconds, and comes back on about every 5 minutes. I'm not sure if that's normal operation. The burner DOES stay on long enough to bring the water in the boiler up to temperature. And the pump IS buzzing during and after this time, so I believe it's pumping. But I would have expected that in proper operation, the boiler's burners wouldn't be cycling every few

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