Heat Plumbing Issue and General Questions...


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Old 10-16-09, 02:17 PM
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Heat Plumbing Issue and General Questions...

He Guys,

This is the first winter in the new house, and we just started using the heat. It is weak, and takes a long time to ramp up. I've noticed some strange things with the plumbing, furnace etc and need some advice.

Firstly:

1948 Cape in Mass
Weil Mclain gas boiler (~10-15 years old)
Hot water heat with radiators (original radiators, upgraded supply and return lines)
3 Zone (B-1-2)

So, I noticed that I had some air in the lines, as a couple radiators were not warming. Bled out the air, and I have some flow and light heat at the radiator.

The aquastat is set at 180F. May want to move it to 190??

The temp gauge on the boiler reads correct, but the pressure gauge reads 0 psi. When I add water to the system, I hear it overflow into the expansion tank, but there is still no pressure read hot or cold....

Here is the strange part. A while back (previous/previous owners) the pipes were upgraded, with a new supply and return for each zone. The new pipe was copper, and the old lines to each radiator were tied into this new loop. The strange part is the loop is a full circle, from the supply to the return at the furnace... The individual radiator lines branch off of this central loop which follows the perimeter of the home. Now, lets assume the flow from supply to return is clockwise around the home. The first radiator on the supply side is at 1-o'clock. The return from that radiator ties back into the supply line at 1:15. Then we hit the next radiator supply feed at 3 o'clock, which returns back to the central supply side at 3:15... My thought was that the radiator was to be fed from the supply side, water travels through the radiator, and then dumps back into the return side to then repeat the cycle. With my system, it seems that most water would sipmly follow the central cupply/return loop and little water would flow to the individual radiators....???

http://www.abramplumbingandheating.c...es/diagram.gif


If you look at the above pic, there is no direct connection from the supplu to the return unless you go through a radiator. Iin my system, the supply and return are directly connected, and each radiators sullpy and return are attachd very close to eachother at the central loop. This is incorrect, no?

So, what to do?

I want to increase the efficiency of the heat system.

Should I call a professional and determine if the plumbing is correct?

Should I aslo clean off the fins in the radiators?

Why would the pressure read 0 psi, yet I still get some heat?

Why is the supply and return directly connected?

Thoughts?

Thanks,

Bryan
 
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Old 10-16-09, 02:37 PM
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Sounds like a mono-flow system. Mono-flow systems are set up with special tees to direct the water to the radiators. If they get air locked it is difficult to get the air out. Your system should be set up with an auto fill valve to keep the system pressurized to a minimum of 12psi to a max of 30psi. If above 30 the relief will pop. If your pressure is at 0psi this is probably your problem. You will hear water gurgling in the expansion tank as your system fills. I would try to add water again, it may take more than you think.
 
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Old 10-16-09, 03:14 PM
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Time for the 'diverter tee' picture again...



If you are familiar with the principle of a 'venturi', that is how these tees work. There are a number of names for them, 'monoflo' is a trademark name that has come into general use for all of them... diverter, venturi, etc are others.

I agree with Skip, yours sounds like a monoflo system.

You may have zero psi in your system, or your gauge may be defective. You need to determine which case it is... but you do need to have at least 12 PSI when the system is cold.
 
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Old 10-16-09, 03:43 PM
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Yup, you guys are correct. I did some more research and it is in fact a one-pipe system with monoflow T's on the branch inlet only. Regular T's at the branch return...

So, I guess I'm okay here.

Now lets address the PSI read.

I let a bunch of water into the system, and still no pressure. Is there another place I can look for pressure?

When I bled the radiators, there was some pressure in the lines, but not a whole lot. If I keep adding water, and the gauge is defective, the over-pressure relief will blow, correct? Could I keep dumping in water until it blows?

Is there another way to check the pressure?

The one thing I did notice was a little puddle (drips) at the 30PSI relief valve, indicating that it may be near that reading and this starting to leak???

Thoughts?

Also, how effective is fin cleaning on the radiators? They have a fair amount of dust and cobweb on them....

If the PSI is low, how does this affect the system?

Thanks Again!
 
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Old 10-16-09, 04:12 PM
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If I keep adding water, and the gauge is defective, the over-pressure relief will blow, correct?
Yes.

Is there another way to check the pressure?
Yes. At your local HD or Lowes or Scotty's or whatever... you should be able to find a tool used by lawn sprinkler dudes that is a pressure gauge mounted on a garden hose fitting that will screw onto a boiler drain. They go for about $10 or so...

Problem with these is that the resolution on the gauge is not good for boiler use because it's a 150 or 200 PSI gauge. You WILL be able to see if it's really zero though, and get an approximate reading of the actual.

You could buy one of those, and then go to a plumbing supply store and pick up a 0 - 50 PSI gauge with the same threads as the one on there... swap it out and be able to read more clearly.

If you have a well stocked 'junk box', you might be able to cobble one together that looks like this... an old washing machine hose, a few fittings and clamps and an old gauge...



Or, you could just replace the gauge on the boiler.

The one thing I did notice was a little puddle (drips) at the 30PSI relief valve, indicating that it may be near that reading and this starting to leak???
That's possible. But, they do often leak at lower pressure also. I and others advocate simply replacing any relief valve that is more than five years old, and doing so every five years. Some insurance companies also stipulate this in the fine print, though few enforce it.

Also, how effective is fin cleaning on the radiators?
Very. You will be amazed at how much even a thin coating of dust can cut down the output of a rad/baseboard. It's well worth the effort, and you might find those long lost Parcheesi pieces!

If the PSI is low, how does this affect the system?
A number of ways, but the first that is usually noticed is that the upper radiators don't produce any heat. You need approximately 0.43 PSI to raise water one foot. If your highest rad is say 20 feet above the boiler, you need a COLD pressure of 8.6 PSI , PLUS about 4 PSI of 'headroom' on top, so 12-13 PSI... the taller the home, the more pressure is needed.
 
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Old 10-16-09, 05:18 PM
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Or just buy a garden hose female to pipe adapter, a 1/2 inch by 1/4 inch bushing to reduce the garden hose adapter to 1/4 inch pipe thread and a 0 to 50 (or 0 to 60 or even a 0 to 30) pressure gauge and connect them up with some Teflon tape on the threads and you have a dandy test gauge with no wasted parts.
 
 

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