Bought house two years ago with four water furnaces. A keep fill is installed because of a leak in the well loop. It doesn't add much volume. A single flow center failed requiring a new dual pump that pumps to all four units in the house. Recently, the low temperature which is highly unusual here caused the main water line to break. This allowed air according to my contractor into the loop through the keep fill. Now the furnace which is highest in the house has an airlock?? and they want to pump the system to remove it. It caused a flow alarm and shuts down. My question is why there is not a pressure tank and an air separator on this system.? Could one not be installed on the uppermost system? My units were installed in 2007, they do not have DHW option, I have three wells for the loops, I was told. The flow center dual Grundig pump is brand new. It is a water only system. How do I keep a keep fill from introducing air, leading to flow alarm and shutting down my unit??? Obviously there must be a fix not a 674 dollar pumping job for the second time this year. Would an air separator work on the loops as on a steam system. Thanx to all in advance.

question 1 is where you are located. Some systems require antifreeze and constantly adding water could lead to disaster.
#2 have you tried loop conditioner? it is a "stop leak" for geo.
#3 you could set the system up with an air seperator if there is no antifreeze requirement.
#4 a non pressurized flow center might solve your problem as well. Often loops won't leak without pressure.
#5 $674.00 is relatively cheap for a flush.

Joe,

You say #3 air separator if no antifreeze requirement.

Why would it only be if no antifreeze? My system with 25% glycol has an air separator? Is that an issue in your opinion?

Trent

I have systems with air seperators and antifreeze, but OP has autofill, so if one is in a heating dominated climate with low temp selected on geo and does not monitor water in (.....antifreeze out), then they better check the antifreeze protection often. That's also why I asked where the system is located.

My system is in Charleston SC area- not supposed to get cold except the last month. The water line which broke was my house supply to be exact. Caleffi apparently makes a separator. Not sure model etc. What about an expansion tank?? Iced in and cold here.

BTW what type of loop conditioner, no antifreeze in line. insulated and lucky so far.

I had a small leak and put a bottle of this in. http://www.geothermalsupply.com/catalog.cgi?id=14.267
I was losing maybe a pint of fluid a month. SInce this, I have had no pressure loss in 9 months or so.

Yes as long as your system has no freeze protect requirement, you can put in air seperator and expansion tank. Again a non pressurized flow center would work and you can try a loop conditioner.

Update
Installer came out and pumped, pro max pumped both the house loop and the well loops sequentially. Unit one is now working but see fan comment below.

Another one (call this unit two) of the units stopped working (after original post but prior to loop pump) and the fan would not come on even after the thermostat was changed to just fan on.
The tech says unit 2 needs a new fan and? A new fan module and that they are one piece- part covered by warranty and 400 to replace.

The night of the pumping job which fixed ? Airlock on unit 1 getting rid of its flow alarm ---In addition the tech disconnected a Honeywell fresh air controller that he said was bad and keeping the fan from running another unit went out.

This time it has the same flow alarm and cuts out - the tech came out and says that it could be an airlock but that would mean it happened the night after a complete pumping but also that the refrigerant was slightly low. Now I have left sc with no functioning units on the first floor. I wondered if pumping had caused a leak to develop leading to low refrigerant and the failure of this unit number three- hours after they left with three units functioning.

At the same time one of the thermostats the one on unit four began reading both on and auto for the fan settings.
We switched the unit two (since no working fan) thermostat for the one on unit four and unit four is running fine.

So this is about three waterfurnaces installed May 2006 (to correct previous posting of 07-found marked on units) that have issues in the same 72 hour timeframe. One supposedly had an airlock but also a fan problem cured by bypassing a fresh air unit.

Now two have fan issues- number two with complete fan failure and number three that has a possible airlock, possible refrigerant problem (not failing til after pumping to solve unit one) and maybe another airlock as it says flow alarm and cuts out. The tech says the fan is only drawing .3 amps on unit three so it also might have a fan problem.

Three water furnaces (premier) out- same week- programmed to fail- gremlin- poltergeist- help.

Addendum

My HVAC guy said he stopped using loop conditioner years ago because it caused pump and parts failures
He says not a good idea

Addendum

My HVAC guy said he stopped using loop conditioner years ago because it caused pump and parts failures
He says not a good idea

Yikes.....I can tell you that flushing did not cause refrigerant leak, but one wouldn't check refrigerant levels after a flush, so why did they? Any history of leaks?

No history of leaks. Their contention when the unit went out right after the pumping was that it had to be due to something else. SO they checked coolant. But also said the fan was too slow. I don't under stand the number of failures in a short time although reading the other blogs these waterfurnaces have a number of coil failures in the time frame of my unit and I guess it has the old coil. Anyway, now have only two units in the upstairs working so if we get a freeze then trouble may get worse. At least it is in SC.

I also don't understand the number of clustered electrical events. If the airlock was the cure for furnace one why can't it be considered a cause of furnace three. Maybe all we did was move the air around. Leading back to the original idea of air separator, would we put one on all four or just two in upper story or only one since its all the same loop?

I'm getting a bad vibe about your technician. While I don't mind someone changing the board and motor at the same time particularly under warranty, I find it's done more often because technicians don't know how to test them.
As I am not a water furnace dealer I have to occasionally buy parts from a competitor who is. I once recieved an ECM motor that was bad out of the box from this WF dealer. When I called to tell them it was no good, they asked how I knew since they couldn't be tested. I enlightened them.
What's more putting refrigerant gauges on when they think the fan may be a problem is silly. Their desire to start with the gauges may be why you are low on refrigerant (from frequent unwarranted connections).
I also agree with you that in troubleshooting we don't like inexplicable coincidence. By that I mean multiple problems on the same unit at the same time. Sometimes they are explainable (i.e. lightening strike damaged multiple parts or conversation with customer suggests nuisance lock outs prior to the failure du jur).

You might be well served by another opinion.

Problem is they are the installing dealer and I think the only water furnace installer in Charleston. Perhaps water furnace can suggest someone. The tech says he wants his boss to come look at he system because he is stumped. The firm is custom climate and they have a good reputation. I don't like so many things going wrong at once, no lightning, could have been brown outs as the area was under ice last week and one night there were power flickers. But I would think that variations are not likely to blow boards. I wish I know how to check the fan on both units. It is calling for the fan and there is voltage but won't start up, hard to believe both fans bad same time. When systems fail usually related to same cause.

There is a tool to test fans. Also damage is often visible, but you have to take it apart. If brown outs cause problems it is immediate.
Let his boss come out if that's your only option

WOuld one of these so called fail safe systems installed on the return from the ground loops just prior to the flow center be a good idea. From what I read it is hard to purge air from wells, makes sense as it is hard to push air down and around, easy to lift hard to push a bubble down, makes me wonder whether our purge just pushed air around. ANyone used one of these fail safe units?

So turns out they want to come out and look at the third furnace which is undiagnosed. Then that same day put two air water separators on the system and one fail safe unit on the ground loop. I am supplying all the caleffi equipment and failsafe unit except the hdpe fittings to attach to the failsafe and four npt to socket hdpe adapters to plumb the air water separators. They are also going to fix a fan for 400 labor under warranty and want 1800 dollars to plumb the air water separators and flush the system. That is 2 grand for one day two guys. Is this reasonable. while they are waiting for the flush that will look at and not fix the other unit. What do you think Joe. Need some input. THe caleffi separators were 125 apiece and the failsafe was 200.

I would get a second opinion

Suggestions in the Charleston SC Area?