chasing persistent air problem

CC.Rob

Circ pump is on return side right before going into boiler. have run 2nd floor zone only at anywhere from 18-25# and still have air. Have not directly observed air coming out of spirovent. During one of the "add pressure and see what happens" episodes I thought I heard it vent some air, but also the boiler relief vented air/water so there was a lot happening at once. If I stand at the boiler during a heating call, I can sometimes hear what I think is air in the return manifold and the pump will cavitate a bit. Don't subsequently hear any air coming out of boiler up to spirovent, though.

The first thing I did when hearing air in the system was replace the spirovent vent head. With vent head off, also checked and replaced the screen/baffle element. Old one looked clean; just one small piece (1/16" or so) of what appeared to be teflon tape in the screen/baffle. Old and worn nearly past identification probably been sitting in there for two years (teflon tape used in connection of expansion tank to bottom of spirovent). In any event the vent head and screen element are new.

Have used a tire gauge on the expansion tank and pressure there is same as reading on boiler gauge.

No tankless coil.

Pressure relief has only kicked that one time described above. Assumed that it was air/water ejection that tripped out the relief before getting to spirovent given the fairly high pressure at the time.

Can post picture this evening.

CC.Rob

Greetings. Am chasing a persistent air problem in my hotwater baseboard system. The moderator on another board suggested this board as a place to ask for help.

The details:

Burnham Series 2 boiler, 2 yr old. Closed series loop, 2 zones (1st floor and 2nd floor), plus a third zone for an indirect water heater. Spirovent installed on supply side between boiler and zone valve manifold. System temp 175-180F, pressure 18-20#. One Taco 007 circulator running all three zones. Taco 571 zone valves.

System worked flawlessly for two years prior to a recent remodel, during which 30-40 ft (total) of pipe and baseboard, plus a toekick heater with monoflow T's on both supply and return were added to the second-floor zone.

The second floor now has a persistent air problem, so we're getting a lot of gurgling, etc. whenever the system cycles. First thought was spirovent failed/clogged during construction. Replaced vent head. No effect.

Tried raising system pressure to 24# to force air out. Quieted the system some, but still hearing air movement through system.

Drained and refilled system. No effect.

Yesterday purged system using drain/valves in basement, and set system pressure and fill valve to 18#. No effect.

Don't think there's a leak as this problem has been ongoing since the beginning of heating season and we haven't seen any water spots on floor or ceiling, and system seems to hold whatever pressure it's set at.

More background is at http://forum.doityourself.com/showthread.php?t=243086

Any suggestions would be most appreciated.

Many thanks.

clammy

pump location

Is your circ pump on the supply or return in any event it seems all your air is migrating to your second floor higher zone >since you have a spriovent i would fill the system up tp 18 psi and run only that zone with the promblem and see if as it's running if air is venting out of your spriovent .Have you disassembled your spriovent and cleaned the element?Have you used another pressure gauge to check you fill pressure jsut in case the boiler pressure gauge is off ?And last but not least how it's piping in general and last but not least does you unit have a tankelss coiland has your boiler safety valve discharged in recent times ?And if all else fails use the find a pro listing one of these gentlemen are more then knoweledge ans can fix or solve just about any thing ps can you post a picture of yur system peace and good luck clammy

Gene_3

Curious

do you have any plastic pipe in there??? Plastic pipe without an oxygen barrier wild bleed oxygen in and destroy your system.

Your exp tank, if diaphram type could also be leaking air, to check properly the boiler pres has to be zero, then exp tank should be at running pressure, also 1 half should be solid and the other hollow when tapped with a metalic object.

I don't see any mention of you purging the system, the system must be purged 1st, then the spriovent will remove any subsequent air.

CC.Rob

No plastic pipe anywhere.

Exp tank is a State Thermo-Flex, 2 yr old, new with boiler install. Upper half solid-sounding, bottom half hollow. Also feels light (i.e. not waterlogged).

Purged all zones yesterday for second time in about a month. Still have air.

The major change to this system is the addition of 30-40 ft of new piping and baseboard on second floor (nobody ever messed with the boiler other than to drain the system to add the new piping), bringing the total loop length of the 2nd floor zone to about 220 ft (estimate probably +/- ~10%). It has been suggested that perhaps (among many possibilities) that the existing circ pump does not have sufficient head to get the air/water mix moving along enough to deal with the air in this newly lengthened loop. Possible? Will adding 30-40 ft plus a monoflow toekick bother this pump (Taco 007)?

clammy

do your self a favor

Take your pump off the return and pipe it pumping away from your expansion tank .Buy dans book pumping away if your handy and can repipe it you8rself or hire a pro who is well versed in piping boilers this way and may be replace that taco oo7 with a 3 speed grundfos to fine tune your systems pump requirements .This is one of the only ways a boiler should be piped i have installed every boiler i've done in over a 10 year period and i've yet on even 1 to have to go back for air related noises or air bound loops maybe a mono flow or raditor hot water job but all in all never a issue .This is probably the way the sysstem should have been piped from the get go but alot of guys save the time and use the pump the way the boiler manafactor sends its mounted on the retrurn ?Do yourself and your systems a favor re pipe it pumping away you will in all likelyhood never bleed your system again imageall that water saved peace clammy