indirect zone problem

brucewo1b

just get 3/4 baseboard tees they have the 1/8 inch tap in the run just put in place of the 90

tm

About every 2 weeks my indirect hot water zone stops flowing (seems to be developing air). There is no hot water - the pump makes alot of noise as it can't seem to move the water. I have an oil-fired Boiler with two heating zones and those NEVER have a problem. I am pumpimg away and have the expansion tank/ air vent in the recommended position/placement. Sometimes this happens in the middle of the night and I am worried that it is not good for the pump.

To fix the problem, I simply shut off the valve at the return just below the drain, and drain out 1/2 bucket of water (and air).

What is the best way to cure this and should I replace the pump to be safe? By the way, I am using 3 pumps, not zone valves. Thanks in advance for any advice. tom

brucewo1b

'Tom

I have had issues with some indirects trapping air even pumping away, I install an auto air vent in the high point going in and out of the indirect and this solves the issue.

tm

Do you mean in the supply and return just above the tank?
What tee fitting supports the air vent with 3/4 copper?
Thanks!

TGO_54

Air bound Indirect

Any chance of a leak in the system? Adding makeup water at a high rate can outpace most air eliminators and will cause air problems.

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Frank_52

what type of indrect is it....????


Do you have a Thermal Expansion Tank ...???

Also do you take the Thermal and Expansion tanks and disconnect them compltly off the off the system to check it they still hold a charge...?????

These should be your 1st steps....

tm

No sign of any leaks.
Are you saying that adding air vents as above may not work?

tm

Not sure what you mean by what "type" - it is a 40 gallon indirect tank heated by 3rd zone of my heating system.
I have an expansion tank (about 1 1/2 years old) connected in the traditional way with one air vent above.
I have not disconnected/tested it yet.

Ps - the tank is a Crown maxi-therm model#MTO40G

Couderay

auto air vents

Like bruce said to do put these vents at the highest points feeding the coil in your indirect not the cold water coming in or the warm water going out.

tm

Can someone explain to me how the air re-developes? I assume it has to do with the incoming cold city water contacting the coil inside the tank, but I don't understand the principle??

tm

I was just looking things over again. The cap was very tight on the air valve (only one I have) on top of my air scoop. I loosened it and heard air escaping. Could this solve it? How loose should it be?

brucewo1b

Yes it could

just unscrew a couple of turns, just needs to be loose enough to let the air escape

tm

Thanks again for the replies Bruce. Water continues to bubble out now. Will that continue?

brucewo1b

If it does

give the float inside a quik flick with small screwdriver, careful its plastic if that doesn't do it you need a new vent, replace it and add a 1/8 in m/f ball valve for easier replacement next time