Spirovent clattering

mark milazzo

Hi
I have a Spirovent microbubble resorber that clatters when the boiler is firing and one of the zones calls for heat. The system seems to work fine except for that noise and was serviced last fall. I did run antifreeze in the system up until last year but had it removed. Any insight would be greatly appreciated.

Jamie Hall

Where is the vent in relation to the expansion tank and the inlet to the main pump? And what pressure is the system running at?

mark milazzo

Hi Jamie
I have attached an image. Does that give you a clear enough understanding of location in relationship to expansion tank and main pump? The gauge on the front to the boiler indicates 17 psi. Let me know if you need more info
Mark

mattmia2

Because the air elimination is in the boiler loop and there is a mixing valve in the system loop it may take it a very long time for any air to work its way to the air eliminator.

mark milazzo

Mattmia2
Thanks for your response. I am not completely following you. Are you saying the Spirovent is doing its job but clattering constantly because it is located in the wrong loop?

mark milazzo

Update: The clattering is not coming from the Spirovent but from a 1" check valve right near it. Did not see it as it was underneath the main boiler unit.

neilc

is that the check to the right of the condensate pump down on the floor ?

can we get another picture from floor level, same scale shot but showing the boiler bottom, and a bit to the right,
any other circs there ?

mattmia2

Does that boiler have an internal pump?

mark milazzo

Hi, Thanks for taking the time to respond. The check valve is right above the condensate pump (pic attached). I have also attached another picture that shows the wider view. The boiler does have an internal pump.

mattmia2

Can you show what is going on to the right of the boiler? Is there a circulator in that loop the boiler is injecting in to?

mark milazzo

Here is a pic to the right of the boiler. One circulator is for HW and the top two are for the first and second floors. Did I answer your question?

mattmia2

Does the boiler pump modulate? I'm not quite sure what they are trying to do with that piping. It seems like they are trying to inject in to a loop but nothing is causing circulation in that loop. Maybe others can explain that better.

I ask if the pump in the boiler modulates because of there is not enough flow through that check valve it will chatter (and i'm not sure it is necessary in the first place).

mark milazzo

It is a condensing boiler. Thanks for all the input so far.

mattmia2

i know it is a mod con, and it has an internal circulator. What i don't know without digging through the manual is if it is a variable speed circulator or if it only modulates the fuel/air. A check valve needs a minimum flow or it will chatter open and closed. It is also possible that the flow always is too low for that particular check valve.

What I am not sure about is how much the other zones affect that flow.

mark milazzo

I misunderstood your question. I did find the specs for the boiler online and it says the following on page 2 "h) Grundfoss 15-58 flanged circulator, 3 speed adjustment with toggle control". I have attached the full spec. I can tell you that while the check valve chatters most of the time when the boiler is in operation, it does not all the time. I think when the hot water zone is running it does not chatter but still observing the operations when various zones or combinations of zones are running.

mattmia2

Is the indirect piped to separate tappings of the boiler from the system? Does the boiler pump come on with a dhw call?

mark milazzo

One feed off of boiler which tees. The internal circulator feeds radiant heat zone in basement, 1st floor heat zone and 2nd floor heat zone. Indirect is fed by its own tap (see picture, back right pipe). So I think that would answer your question that the boiler pumps does not come on when only dhw? The internal pump is
set to setting three. I put it to setting one today and the check valve clattering went almost completely away. Should I leave it to one? Is that my issue?

Thanks for taking the time to respond to this thread. I appreciate it.

mattmia2

Speed 3 is probably too much flow for that application given there is only that injection piping attached to the boiler but someone else could do the calculations for you. The injection piping is only 3/4" but there is also only around an equivalent of 5' of it with the fittings. The spec of the flow the boiler wants for full output and the head loss of the boiler at the flow will be needed from the manual.

mark milazzo

Thanks. I will continue researching the appropriate setting

mark milazzo

mattmia2 said:

Speed 3 is probably too much flow for that application given there is only that injection piping attached to the boiler but someone else could do the calculations for you. The injection piping is only 3/4" but there is also only around an equivalent of 5' of it with the fittings. The spec of the flow the boiler wants for full output and the head loss of the boiler at the flow will be needed from the manual.

Hi
Following up on this problem. I did finally speak with the manufacturer. Speed 3 was too much given the piping layout. It should be on 1. Also found that in the manual. Set the speed to 1 and the chattering has almost completely gone away. Thanks for your help Mattmia2.