[Donl1150]

I have a geothermal radiant in floor heat system. For some reason, one bedroom zone won't heat properly. The circulation pump feels warm and I can feel a slight vibration so I have to believe that the pump is working. There are no zone actuation valves on the system, just circ pumps.

I have been told there could be an airlock in the zone thus preventing proper water flow. In an attempt to clear this airlock, I have turned off all zone circ pumps except the one in question in hopes that would provide enough pressure to 'free' the airlock.

Does this sound logical and actually might work?

 

[beenthere]

Unfortunately, circulators are not actually water pumps. So it won't be able to move air out of an air locked zone.

You will have to bleed/purge the air out manually. If you can post pics of the geo and the piping around the circs. Might be able to tell you how to purge your system.

 

[Donl1150]

Here are the zone circulation pumps. Note that there are no actuation valves, only manual isolation valves.

Here are the two geothermal heat pumps. The one on the right is a 3 ton unit and the left one is a 4 ton unit. The right actuation valves on both units are for the well supply water. The left actuation valves on both units are for the resultant hot water which is piped to a buffer tank. The valves are controlled by an aquaststat in the buffer tank. When a zone thermostat calls for heat, it activates the circulation pump for that zone and hot water flows to the zone from the buffer tank.

 

[Bob Sanders]

That's a lot of money on pumps, pump maintenance, and electricity. A single pump will do you with electric zone valves on each zone. just thought I would mention that.

Are there any bleeders on the rads and do you have access to them?
Is this a problem every year?

 

[Donl1150]

If you mean radiator (rads ?), there are none. It is an in-floor radiant system. What I do have in various places throughout the house (typically in a closet) are these things:

Here is a close-up of the device on the end, which I have a feeling is what you may be referring to:

 

[Donl1150]

We have only been in the house (8 years old) for one winter prior to now. This is the first time the problem has surfaced.

p.s. - I have been told by a contractor that did some other servicing on the system that the entire system was very well designed but certainly WAS a little overkill.

 

[Bob Sanders]

Yes. That's the babe. It looks like an auto bleeder. Make sure the cap is loose so that air can escape.

 

[Bondo]

What I do have in various places throughout the house (typically in a closet) are these things:

Ayuh,.... I haven't used that manifold, but that's an auto-bleed valve on the left, as Bob says, make sure the cap is just loose,...

I believe each of the 4 black things, bleed each circuit,....
Figure out which one is the faulty zone, 'n crack the bleed open, 'n let the air out,...

There should be an auto-fill valve somewhere, to maintain the overall water level/ pressure to 'bout 12 psi,...

Lookin' again at yer picture, those black things might be some sorta propositionin' valves, 'n not circuit bleeds,...
Maybe the 1 on the bad zone just needs to be fully opened, fully closed, 'n reset to 'bout where it is now, to work again,....
Or maybe it just needs to be opened more,...

 

[beenthere]

Here are the zone circulation pumps. Note that there are no actuation valves, only manual isolation valves.

Here are the two geothermal heat pumps. The one on the right is a 3 ton unit and the left one is a 4 ton unit. The right actuation valves on both units are for the well supply water. The left actuation valves on both units are for the resultant hot water which is piped to a buffer tank. The valves are controlled by an aquaststat in the buffer tank. When a zone thermostat calls for heat, it activates the circulation pump for that zone and hot water flows to the zone from the buffer tank.

The valves above the cirs are your purger valves that you use to get air out of the loops.

Before you try to purge though. The 5th one fro the left. The valve above and under the circ is closed. If thats the zone not heating, that may be the only reason why. Was that circulator changed out in the last year or 2.

Open those valves slowly.

 

[Donl1150]

Thanks for the input. I should have mentioned that one zone that is shut off is that way on purpose. It serves a screened in porch area that was eventually going to have the screens replaced with windows thus making it a four season porch area. The screens remain and it is still exposed to freezing weather.

 

[beenthere]

Okay. Then try purging the non working zone. close the valve at the circ. connect a garden hose to the drain valve. Open the drain valve, and add water to your system and see if air comes out.

 

[Bob Sanders]

Thanks for the input. I should have mentioned that one zone that is shut off is that way on purpose.

A screened porch outside? Be careful. If you're not running glycol then you risk freezing/breaking that zone.

 

[Donl1150]

Correct. It does have glycol. I am calling in the pros to find the problem.

 

[Donl1150]

Well, the pros were here. They bled the system...no air came out, only glycol. They replaced the circ pump and said that should take care of the problem. I am not totally convinced. It has been 7 hours and the room still reads as it did prior...63F. The stat is set at 69F. I know it takes time for radiant systems to respond so I will see what it looks like tomorrow.

My question though is: Are there flowmeters available that can be put on the individual zone lines so you can verify the water is flowing? Note that there are flowmeters on both heat pump discharge lines that serve the buffer tank.

 

[beenthere]

Yes, there are flow meters that can be put on the individual zones/circuits.