Bleedingh radiators and the expansion tank...

[hotblues20]

Greetings brothers ~

I have been searching for a while now on bleeding radiators...since the bleeding I did last night seemed to cure about 75% of my insufficient heat issue, I want to be sure I am doing it properly going forward.

Do you go from nearest to the boiler to farthest, or vice versa? Somehow I would think farthest 1st...

Boiler should be running at normal operating temp when you bleed, right?

Bleed at least a quart at each radiator? Less? More? How often when a system shows trouble? (I am figuring a quart each, done every week until the insufficient heat problem is gone?)

What about the expansion tank? Mine is a metal cylinder maybe 5 gallon capacity, sitting just above the boiler. Should this thing be bled as well? I understand they can sometimes become water-logged...

I hope that is comprehensive as far as what Q's come up for bleeding FHW radiators so those that come searching can be helped. Let's hear from the experts!

Thanks,

Bluesman

[BinaryBillTheSailor]

Start at the far end of the circuit and work your way back towards the boiler. In a multi-story system, you would start on the highest floor and work downward.

Don't get hung up on how much you drain, other than to remember that if you bleed too little, you are more likely to have to repeat the excercise. If you Bleed too much, no real harm is done. If, after doing the bleeding, you still have a cold radiator somewhere, try repeating the whole thing again. If that doesn't do it, THEN you might consider that there is some other issue at work.

The expansion tank doesn't need to be emptied very often, but it does need to be emptied every once in a while. I usually do mine twice a year. Follow back from the expansion tank to find the inline valve that shuts it off from the rest of the system. Then simply empty it via the drain valve a few gallons at a time, into a bucket. If you have a short length of hose (old washing machine hose?) you can attach that so you can set the bucket on the floor rather than trying to hold it up all that time. The drain valve on the tank is special, in that it has a special tube in it that lets air in through the valve at the same time as the water is coming out. If that vent tube is clogged with sediment, the tank will never drain. If you have a service contract, that might be a covered repair. My serviceman replaced it once during an annual cleaning without charging me anything.

Don't forget to reopen the in-line shutoff valve between the tank and the system when you are done!

BB

[m Ransley]

I have never bled more than air out. Air is what you do not want in the system. You need to be sure your water level is correct since you removed some. 12lb cold is normal. What is your water temp set at. raise it , try 185

[m Ransley]

I have never bled more than air out. Air is what you do not want in the system. You need to be sure your water level is correct since you removed some. 12lb cold is normal. What is your water temp set at. raise it , try 185

[BinaryBillTheSailor]

Sometimes the air bubble is trapped downline somewhere. Bleeding some water often moves the air bubble to where it can reach the bleeder and be expelled.

BB

[Gary R. Lloyd]

Unless you want a whole new set of problems, leave the expansion tank alone.

_______________

Gary R. Lloyd CMS HVACR Troubleshooting Books/Software Written by a veteran Service Technician

[Gary R. Lloyd]

12 psi cold may or may not be normal depending upon the vertical height of the system.

_______________

Gary R. Lloyd CMS HVACR Troubleshooting Books/Software Written by a veteran Service Technician

[BinaryBillTheSailor]

That's just plain silly. Draining the expansion tank is very easy. No more complicated than say, backwashing a swimming pool filter. I've been doing it twice a year for a LOT of years.

Sometimes "pros" get funny ideas about things. I think this is one of those times. You may have drained a few thousand expansion tanks and ran into problems 20 times, so now you think it's a hazardous and risky thing for anyone but a professional to deal with. I already advised the guy that if his drain valve is clogged up, his service contract will probably cover it. I didn't recommend that he try and replace the valve by himself, in the unlikely event that it needs replacement.

I knew a "professional" who worked in a G.M. transmission repair facility. He was of the opinion that GM transmissions were lousy, because every one of them he saw was broken! 8^)>

BB

[Gary R. Lloyd]

This system does NOT show symptoms of expansion tank problems, and given the OP's level of expertise he is likely to do it wrong.

For that matter, what makes you think YOUR expansion tank needs annual draining?

_______________

Gary R. Lloyd CMS HVACR Troubleshooting Books/Software Written by a veteran Service Technician

[BinaryBillTheSailor]

Nobody is saying that the expansion tank has anything to do with his other problem. He just asked about how to drain it, which is a simple and straightforward procedure. I'm betting he can handle it just fine. He has shown that he asks questions when he's not sure of himself. If he opens that drain and nothing comes out, I'm pretty sure he'll stop and post a question in this newsgroup about how to proceed.

Because I reach up and feel that it is heavy and full. Draining it also serves to evacuate some sediment, which if left alone WILL cause problems. There is certainley no harm done by draining it pweriodically, and it CAN help you to avoid other issues, such as an overpressure safety valve dumping a few gallons of water on your floor while you are away on vacation.

BB

[Gary R. Lloyd]

That's just plain silly.

_______________

Gary R. Lloyd CMS HVACR Troubleshooting Books/Software Written by a veteran Service Technician

[William W. Plummer]

First, the expansion tank is there to act as a cushion against sudden pressure changes such as the automatic filler clunking on and off. Also, it accomodates changes in air pressure. The expansion tank is only a chamber with a flexible diaphragm halfway up. That diaphragm will last about 20 years, but can rupture.

Second, the pressure in your system is largely set by the automatic filler valve. A typical range is 6 to 22 psi. It's built into the valve.

Third, air in the system should escape via a relief valve, typically on the stem up to the expansion tank. Some systems have little air separators on local high points around the system. These are valves that have cardboard in them. Air escapes while the cardboard is dry but when water hits the cardboard it swells up and stops the flow.

Fourth, it sounds like you could benefit from an hour of a friendly plumber's time. Have him explain all the parts of your system and answer your list of questions. In the end this will save you time trying to guess what's going on.

[Bubba]

OH for god sakes Ransley. Why dont you STFU on stuff you know nothing about.

12 lb is normal?? For what? How about a 2, 3 or 4 story bldg? 12 lbs wont cut it there, "butt bait".Try 12lbs on a single story ranch with no basement. That would be what is called unnecessary overkill. Its related to the height of the radiators from the boiler. Stick to something you know something about..............like porking jimmy, my pull toy pet. Bubba

[Bubba]

Still wrong you bone head. Try having NO AIR in your expansion tank. Then tell me how many problems you have with your system. Ransley, you are a moron without a clue. Hop on your camel and ride son, ride off into webtv land Bubba

[Bubba]

The more you drain, the more you refill. Unless you are refilling with clean distilled mineral free water (you arent) you are introducing added minerals each time. Its a balancing act. You have to add water once in a great while but the more you add the more minerals you add. Expansion tanks do NOT need to be drained twice a year. If you have to you need to find out why. Anytime you drain water at the boiler, you usually wind up with air in the system at the upper radiators. Then you have cold radiators. Then you have a call back. Purging air from a hot water system may be easy for you but it is costly when a technican has to do it. I dont drain water or purge radiators for free. Bubba

[BinaryBillTheSailor]

Please notice that I not only said "That's just plain silly in response to your baloney, but I went on to explain WHY. I'm not surprised at all at this pouint that you had nothing to back up your post. I guess it was just one more easy excuse to post your SPAM sig.

BTW - A full expansion tank CAN cause air in a system. I'm betting you don't know why or how. Good thing you retired so you won't be inadvertantly ripping people off due to your incompetence.

BB

[HeatMan]

insufficient

Okay, what if it's a diaphragm style tank?

Oh, and if you have to drain a tank as often as you say, you have another problem......

[Gary R. Lloyd]

Sorry, I try not to feed trolls. Think whatever you want. Or don't.

Sheeeeeeeeesh.

Here comes the SPAM again:

_______________

Gary R. Lloyd CMS HVACR Troubleshooting Books/Software Written by a veteran Service Technician

[BinaryBillTheSailor]

Did I say I HAVE to drain the expansion tank? No wonder you can't trouble shoot your way out of a paper bag.

There is an HVAC newsgroup that gets very upset and nasty if anyone who is not an HVAC professional posts a question there. How about these money grubbing, incompetent, SPAMMING, low-lifes stay out of alt.home repair.

Bite me!

BB

[BinaryBillTheSailor]

Bingo!

Clearly that's the only reason you post here at all. You sure aren't looking to help anybody you can't bill by the hour for your incompetence.

Meanwhile, my advice seems to be helping Mr. Blues with his problems