Water Flow sounds through rads and intermittent groaning

robinontario

Hey There,

I had an old boiler finally bite the dust so I had a Laars Minitherm installed. Since then there's been a loud groaning the intermittently comes through the rads and walls. It's a two zone system with the first going to radiators on the main and second floors and a second branches off of that going to in-floor heating on the main and basement.

Both zones have pumps, but I'm only hearing the sound when the in-floor zone is active. And it changes pitch from high to low to almost gone when I close the bypass valve.

I've tried bleeding the rads, but there's only water coming out. And the service guys who've come in haven't been much much help.

I'm also hearing a constant water flow sound when I open the rads to a certain point. It sounds like a pipe when the shower is running.

Any ideas?

Intplm.

Hi there @robinontario .
The noises you are describing sound like:
Air in your system?
A temperature and or balancing issue?
Pipes needing to be hung/ supported?

Post three or four or more pictures at different view points to get a better look.

robinontario

Here is the system, in a nutshell.

robinontario

Closer on zone pumps.

robinontario

To the right of those is the intake. Air cushion is off that.

robinontario

Out and pressur gauge on the left. Return on the right. Also there's a temperature gauge on zone 2 line. There's an airscoop off the main. Pros want $200 to replace it.

robinontario

Here it is. I'm just gonna replace it myself.

kcopp

From the pictures you have posted it would appear to me that the boiler is piped wrong.
That boiler is very low mass... meaning that the flow rate is VERY important. It should be piped w/ a primary/ boiler loop and the individual zones off of that w/ their own pumps.

Intplm.

What you show in the pic that you say is a air scoop is not a air scoop but a air vent, or what is called a hi-vent.
This vent is screwed into a air scoop? I can't be sure it is as none of your pics. show what it is installed on.
If you do not have a micro bubble air separator made by caleffi or spirovent, your problems will surely continue.
Changing the hi-vent will not fix the problems that you are describing. A micro bubble air separator is a very good start in correcting your described issues. I would look to doing that.

Intplm.

Can you post a few more pictures farther away so that we can see the hole system as installed, or is it to tight an area to do that?

robinontario

P> @kcopp said:
> From the pictures you have posted it would appear to me that the boiler is piped wrong.
> That boiler is very low mass... meaning that the flow rate is VERY important. It should be piped w/ a primary/ boiler loop and the individual zones off of that w/ their own pumps.

That is the case. Primary loop does 2 rads on main floor and three on second. Secondary loop branches off that to do main floor and basement radiant floor heating. It has it's own pump.

robinontario

> @Intplm. said:
> What you show in the pic that you say is a air scoop is not a air scoop but a air vent, or what is called a hi-vent.

My mistake! Still getting used to the terminology. Air vent is at the top of the main loop stack. Too tight to get it in the photo.

> If you do not have a micro bubble air separator made by caleffi or spirovent, your problems will surely continue.

> Changing the hi-vent will not fix the problems that you are describing. A micro bubble air separator is a very good start in correcting your described issues. I would look to doing that.

Can this go anywhere on the line?

I've noticed that the noise is lower with low setting on main circulation pump and only really comes on when the secondary pump is active. It's also completely gone if I crank open any rad that was previously closed.

Intplm.

Try to get a pic of what is below the hi-vent

kcopp

robinontario said:

P> @kcopp said:

> From the pictures you have posted it would appear to me that the boiler is piped wrong.

> That boiler is very low mass... meaning that the flow rate is VERY important. It should be piped w/ a primary/ boiler loop and the individual zones off of that w/ their own pumps.



That is the case. Primary loop does 2 rads on main floor and three on second. Secondary loop branches off that to do main floor and basement radiant floor heating. It has it's own pump.

No.
A Primary loop ONLY does flow for the boiler... nothing else. That is not what I see from the pictures. At a very minimum you need to have a bypass to divert water back to the boiler as it runs.

robinontario

Hivent is at the top. Bypass is the top knob.

SuperTech

It's kinda hard to tell from the pictures but where is the expansion tank in relation to the circulator pump? Ideally you want to have the microbubble resorber air eliminator and fill valve, backflow preventer and expansion tank first on the supply pipe coming out of the boiler. Next in line should be the circulator, pumping away from the expansion. This is critical for air removal and prevention of air related problems.

robinontario

Yes, expansion tank and fill valve is first stop off the out from the boiler before the circulator pump.

robinontario

I do want to point out that the old boiler was a workhorse from the early 80s. The noises didn't start until after the new one was put in. In that time there was also a water main break in the area... not sure if it's relevant but the water was off for s few hours.

There's no air coming out when I bleed the rads. Could there be other air in the system that isnt being removed? Also, could the issue be in the installation?

Intplm.

Hard to say if the "issue" or issues are entirely because of the installation. Shame we can't see enough of the boiler.
@kcopp makes a very good point and observation above.

I'm afraid you are going to have to push your service company for answers.
This issue might just be the nature of the beast, so to speak. But then, I can't hear it from hear.