Upgrading and Mounting Larger Expansion Tank

breakityourself

I just moved into a place with a roughly 40 year old hydronic heating boiler feeding about 10 CI radiators on two floors above the basement where the boiler is. It looks like at some point they replaced an old style expansion tank (it's still hanging between the joists) with an Amtrol EX-30. Based on how it's installed with some soft copper tubing angled off to the side and just held up by a ton of pipe straps I'm guessing it was a DIY job from the previous owner, and I'm thinking they didn't size it properly because the pressure relief is discharging water when the temperature gets up to around 170. There was also already a bucket underneath the relief valve when I moved in.

The current mounting "works" for the EX-30 but if I'm going to upgrade to a larger tank then I want to make sure it's secured properly. From what I gather normally the tank just hangs from the piping, but unless I make some larger changes to the pipes it's not really simple to do so. Would the best way to do it be to attach it to the cement wall in some way and just replace the pipe going to it with something longer? Are there some other simple changes I should do while I'm at it? I'm thinking probably getting an EX-60 would be sufficient since it only expels water when it gets to a higher temp.

Other than this the system seems to run fine. It seems to have no issue heating up or getting all the radiators hot. I had someone come to do a checkup on it and aside from trying to sell me a whole new system they didn't really do or suggest much other than tell me the PRV needed to be replaced because it dripped and the temperature and pressure gauge was ancient and no longer could read the temperature. They also pointed the expansion tank installation was pretty janky, but said as long as it worked it was fine. That was before I noticed it was reaching 30 PSI when hot.

I replaced the PRV and gauge myself. I recharged the expansion tank from about 4 to 12 PSI, and checked that it didn't have any water in the air section. I've left the valve shut off before the pressure regulator, and the water pressure for the system has been around 15 when cool.

Here are some pictures of how it looks currently.

EdTheHeaterMan

That tank is designed to be supported by the pipe it is connected to
That said, the pipe should be able to support the weight of the tank with the tank full of water. It should never be full of water when it is in operating condition, But it may fail someday and it could be full of water.

The next size up is a #60 tank, that is designed the same way. The pipe it is connected to should hold the weight of the tank full of water.

Any tank larger is usually floor (or shelf) mounted and that piping would need to be rerouted to accommodate the new location.

breakityourself

That's probably the intended design, but the pipe it's currently connected to is not strong enough to support it on its own. The pipe is just connected with compression fittings and can be bent with very little pressure. There doesn't seem to be a good place to tie it into the stronger pipes without bigger changes. I'd prefer to keep the pipe changes down to just what might be necessary, given the age of the system and the pipes.

STEVEusaPA

Yikes!

EdTheHeaterMan

OK, I see your point. The fact still is that you need to support whatever fitting has the female thread that is pointing down to the ground.

You have three choices
1. Put a new pipe in, or get a piece of all-thread rod, a flange, and a split ring pipe hanger to support the existing fitting.


2. Change the expansion tank location
3. Strap the tank up in the current well-crafted configuration. You don't need to use the same strap material, you can use lots of duct tape, baling wire, or build a pillar with Lego Blocks. You would be amazed what you can do with lego blocks.

SuperTech

Lego blocks might be a big improvement.

At the bare minimum ditch soft copper,  use type M or L copper.  Redo the piping to the tank. Commercial made mounting kits are available for expansion tanks, or use threaded rod and unistrut. If you can't solder copper pipe compression fittings or shark bite might be an option.  Or threaded black pipe. 

EdTheHeaterMan

SuperTech said:

Lego blocks might be a big improvement.

Thanks

don't I at least get an "Insightful"? or a "LOL"?

breakityourself

SuperTech said:

Commercial made mounting kits are available for expansion tanks

Are you referring to something like this?
If I went with something like that where the pipe doesn't need to hold the weight would it make sense to use something like pex or some other flexible piping?

Using some regular copper with a few elbows seems like another good option. I'd have to buy some soldering equipment, but I think I could handle that also.

Would it be worth adding some kind of air purge on that line while I'm doing this, or since it's branched off the main feed it wouldn't be as useful?

Steamhead

"Hey Bubba, hold my beer........"

SuperTech

breakityourself said:

Commercial made mounting kits are available for expansion tanks

Are you referring to something like this? If I went with something like that where the pipe doesn't need to hold the weight would it make sense to use something like pex or some other flexible piping? Using some regular copper with a few elbows seems like another good option. I'd have to buy some soldering equipment, but I think I could handle that also. Would it be worth adding some kind of air purge on that line while I'm doing this, or since it's branched off the main feed it wouldn't be as useful

breakityourself said:

Commercial made mounting kits are available for expansion tanks

Are you referring to something like this? If I went with something like that where the pipe doesn't need to hold the weight would it make sense to use something like pex or some other flexible piping? Using some regular copper with a few elbows seems like another good option. I'd have to buy some soldering equipment, but I think I could handle that also. Would it be worth adding some kind of air purge on that line while I'm doing this, or since it's branched off the main feed it wouldn't be as useful?

Check out the Webstone expansion tank fitting. It has an isolation valve and drain valve built into it. That's not the mounting kit I was thinking of,  but it would probably work. 

Ironman

Uh, has anyone noticed that a compression  tank should be used with that system which doesn’t have an air separator?

hot_rod

Yes an air purger @Ironman mentioned would be a nice addition. With all that perforated plumbers tape, make two loops from the joist above and hang the new tank horizontally.

HomerJSmith

The best way to support an Amtrol #60, I find, is with Sky Hooks.

SuperTech's picture also works.

mattmia2

Did you remove the pressure form the system when you charged the tank?

The proper way to size the tank is to estimate the total volume of the system bu estimating the amount of piping of each size and the volume of the emitters. That tank seems like it should be large enough but you don't know without measuring.

SuperTech

@Ironman makes a great point,  that system was probably originally equipped with an Airtrol tank up in the ceiling, so it didn't need an air separator or any air vents. 

The best thing to do is to install a microbubble resorber air eliminator on the supply and connect the expansion tank to that. I would also relocate to circulator so its pumping away from the expansion tank. 

clammy

Usually if I’m not hanging off the bottom of a spriovent I ll use a hydroclaw or one of those steel remote tank mounts anything close to a 60 and I ll just order a floor mount no sense hanging a 60 when it goes it’s gonna be a mess and heavy so just get a stand alone and save the hassle . Peace and good luck clammy

breakityourself

hot_rod said:

Yes an air purger @Ironman mentioned would be a nice addition. With all that perforated plumbers tape, make two loops from the joist above and hang the new tank horizontally.

That sounds like a nice simple option. Is the suggested vertical orientation mostly to avoid undue pressure on the fitting, which would be avoided if the tank itself is being held up?

Where would be the best place to put the air purger? Would it make sense to do it on the line feeding the tank, or should it really be in the main piping? Is it something that's very important to add retroactively?

mattmia2 said:

Did you remove the pressure form the system when you charged the tank?

The proper way to size the tank is to estimate the total volume of the system bu estimating the amount of piping of each size and the volume of the emitters. That tank seems like it should be large enough but you don't know without measuring.

Yes, there is a valve right before the pipe to the tank. I closed that and opened the fitting enough to let water come out. When water stopped coming out I measured the pressure.

I think estimating the full volume of the pipes and rads is a bit beyond me. I looked at the amtrol size calculator and it seemed like my system was either a 60 or a 90, but I don't know the output btu only the input. It's 187,500 btu input.

SuperTech said:

@Ironman makes a great point,  that system was probably originally equipped with an Airtrol tank up in the ceiling, so it didn't need an air separator or any air vents. 

The best thing to do is to install a microbubble resorber air eliminator on the supply and connect the expansion tank to that. I would also relocate to circulator so its pumping away from the expansion tank. 

It's still there in the joists, haha.

The circulator is currently on the return side.

Steamhead

If that were mine, I'd pressure-test the old tank to 30 PSI or so with water. If it passes, I'd put an Airtrol fitting on it, and a tank drainer, hook up the Airtrol to a new air separator, and never have to worry about another blown diaphragm.

Plain steel tanks work fine if you pipe them in correctly.

SuperTech

Yes, nothing wrong with the old tanks, especially considering how many modern diaphragm tanks I see fail. A compression tank with airtrol fittings seems like a more reliable option.  Just have to drain a little water out of it once in a while. 

hot_rod

The air separator should be at the hottest point in the system, right on the supply out of the boiler, red line.
If you leave the circ where it is, looks like there is a valve on the suction side? connect the tanks and fill valve there.
You can use two expansion tanks, just buy another #30 and connect it with the one you have.

breakityourself

Steamhead said:

If that were mine, I'd pressure-test the old tank to 30 PSI or so with water. If it passes, I'd put an Airtrol fitting on it, and a tank drainer, hook up the Airtrol to a new air separator, and never have to worry about another blown diaphragm.

Plain steel tanks work fine if you pipe them in correctly.

Good thought, but I'm not sure it's worth the effort. The drain valve is corroded and frozen, and some quick attempts to wrench off both ends were (not surprisingly) unsuccessful. Seems like some effort would go into it and I'm not even sure how usable it still is. And I don't want to accidentally do something to that pipe that runs right along the back of it while fighting with it.

hot_rod said:

The air separator should be at the hottest point in the system, right on the supply out of the boiler, red line.
If you leave the circ where it is, looks like there is a valve on the suction side? connect the tanks and fill valve there.
You can use two expansion tanks, just buy another #30 and connect it with the one you have.

There are two circulators for two zones. One is barely used, just for the basement. That one is red and has a drain valve on the suction side. The grey circulator has a drain valve on the exit side.

The copper sections on the supply side right off the boiler looks like a good spot to put in an air separator. But I don't think it would have great clearance to put the tank hanging from it, and would be a little in the way. I think I'll keep the tank on the same branch it's currently on and when I have a little more time I'll cut into the copper pipe right off the boiler to put in an air separator. I'm currently leaning toward sweating in some copper following roughly the same path, but adding in a second tank so I can reuse the one I have now.

You guys have been really helpful, I appreciate all the advice.

breakityourself

I wanted to give an update and further thanks for all the suggestions you guys gave me. I ended up getting the tools and supplies to sweat in some L copper pipe and installing a second tank. Funnily enough, there was a line of copper hanging in the tool room the seller left which was literally exactly the amount I needed. I'm pretty happy with how it came out despite being my first time, and so far no signs of leaks.

Some pictures:

Jamie Hall

Good for you! Only trouble is, you may find yourself enjoying playing with this stuff!

SuperTech

This brings a big smile to my face. Its great seeing probably the worst expansion tank installation change into decent looking work that you can take pride in. Thanks for the update.

Dave T_2

Nice job!

breakityourself

Jamie Hall said:

Good for you! Only trouble is, you may find yourself enjoying playing with this stuff!

It might be too late for me. I already took apart my RA832A relay to solder on a new C wire a couple weeks ago, so that I could hook up a nest thermostat. My next plan is to replace a bunch of multi-turn valves with quarter-turn in the bathrooms and kitchen. Lots more to do after that. Old houses seem to have no shortage of projects.

SuperTech

breakityourself said:

Good for you! Only trouble is, you may find yourself enjoying playing with this stuff!

It might be too late for me. I already took apart my RA832A relay to solder on a new C wire a couple weeks ago, so that I could hook up a nest thermostat. My next plan is to replace a bunch of multi-turn valves with quarter-turn in the bathrooms and kitchen. Lots more to do after that. Old houses seem to have no shortage of projects.

Please don't put in a Nest! Not a good option for hydronic heating.  I think its an overpriced,  overrated POS. I get more service calls for Nest thermostat problems than any other thermostat.  If you need wifi control of your boiler I'd recommend using a Honeywell 

If you want to keep upgrading your boiler consider adding a good microbubble resorber air eliminator and change to a pumping away setup.  Then you will have a great boiler setup. 

breakityourself

SuperTech said:

breakityourself said:

Good for you! Only trouble is, you may find yourself enjoying playing with this stuff!

It might be too late for me. I already took apart my RA832A relay to solder on a new C wire a couple weeks ago, so that I could hook up a nest thermostat. My next plan is to replace a bunch of multi-turn valves with quarter-turn in the bathrooms and kitchen. Lots more to do after that. Old houses seem to have no shortage of projects.

Please don't put in a Nest! Not a good option for hydronic heating.  I think its an overpriced,  overrated POS. I get more service calls for Nest thermostat problems than any other thermostat.  If you need wifi control of your boiler I'd recommend using a Honeywell 

If you want to keep upgrading your boiler consider adding a good microbubble resorber air eliminator and change to a pumping away setup.  Then you will have a great boiler setup. 

I got the thermostat through my utility company for cheap and can't return it. If it dies maybe I'll get something else. It's so far a lot better than the old analog dial thermostat which wouldn't come on unless it was set to way above the displayed temp.

I'm planning on adding an air eliminator at some point. Is on the list.

SuperTech

I'm pretty sure the utility company gives them away so they can monitor and sometimes control energy consumption by your equipment remotely in times of a heavy load on the power grid. I don't think that applies to a boiler.  I don't like that thermostat because its automatic setback feature, that's not the proper way to control a radiant or hydronic heating system. I'm a believer that keeping the system at the same set point 24/7 the most efficient way to control the system.  I also like to see an outdoor reset control being used for greater efficiency.