bleeding a hot water heating system

[szeik]

Hi,

We have a relatively new gas boiler - 5 years old I think. This last year I've been hearing a lot of gurgling in the pipes and I figured it was time to bleed the system.

Well, I seem to have done more harm then good. I bled the upstairs radiators and at first I heard some air come out - or maybe it went in through the bleeder valve. I'm not sure. But now there is no heat at all on the second floor which has 3 radiators. Downstairs seems to be functioning fine. Upstairs I did not get any water coming out of the bleeder valves.

Downstairs I did get water coming out when I bled the radiators.

I am thinking the system must need a lot more water in it which I know is supposed to fill automaticaly but maybe that part is not working.

Prior to my trying to do this we were getting some heat on the second floor. Kind of strange. I think I must have let more air into the system probably because it is already full of air and not functioning properly.

I guess it's time to call a professionsal.

Any ideas what is going on here?

Thanks in advance, Steve

[m Ransley]

The water level is likely low, is the pump running, what is the water pressure when cold. Wait for it to cool and open up the feed, I have an auto feed but dont trust it and keep the line valves to it closed, many people keep them closed or lift up on the little bar across the top of the feed valve to see if you can get it to feed water. With only air comming out upstairs you are low on water, start by adding only 2lb note pressure cold and hot. For 3 floors I run 12-14lb.

[szeik]

Where is the feed? I see a few turn valves and a few levers but I'm not sure which one turns puts water into the system.

The pressure is almost 0!!

Water temp says 140 at the moment.

Thanks for the tip about cooling the system first. I was wondering about that. Cold water in a hot boiler seems like it could spell disaster.

Should I call the expert here or is this really a do it your self project for a moderately handi person? Actually moderately may be overestimating my abilities.

Thanks, Steve

[Edwin Pawlowski]

Is the boiler also used for domestic hot water? If so, there are two feed valves, one for domestic water, the other for the heating water. Follow the cold water line to the boiler. It is probably running across the ceiling and then drops down to the boiler. At some point, it will split off. One valve will be on the line feeding the domestic water. It will be full open. The other line will go through a setup (often made by Watts) that has first, a fill valve that has a lever on the top, then a pressure relief valve that have a pull handle on the top and may have a pipe on the bottom to direct any blowoff. The feed valve is in that line ahead of this assembly. In my case, the fill and pressure valve are on the back, but the fill valve is on the front. Find it, and see if it is open. If it is closed, when you do open it you will probably hear water running.

Once you are sure it is open, then you can go back and bleed the air. . It may take a couple of tries to get all the air out. Do the bleeding cold, but then turn the heat on and while the circulator is running, if you hear air, bleed it again. If needed, again and again. Air sometimes get into pockets. I have a baseboard system and it took four times to get the first floor bled properly and the water to circulate properly. If there is not enough water, the pump can cavitate and not push the water through.

You probably also have a drain valve on the return pipe of the heating system. You may want to drain some water there while the pump is running. That is where I finally got all the air out. Just open it a crack and it may sputter as the water passes and air comes out.

Keep in mind, as long as you have some water in the system, you won't do any damage so try it a few times before spending $100+ for a service call.

[buffalobill]

[m Ransley]

You have a hot water output pipe and cold return on the boiler. does the pump run? The fill valve-valves should be on the boiler return going to city supply. I would not just turn it on and leave it since you could overfill it fast if your system is small, at 35lb your pressure relief would open, you don`t realy want to get above 8-10 cold to start. I run 12-15 on a boiler in a basement of a 3 story, less hight you need less pressure. You only want enough water in it to get all the air out and heat radiatore evenly when hot. I have never blead a system cold,[but try it], and not running since pressure builds as the boiler heats.

[szeik]

The way mine is set up the cold water feed is turned on but there are 2 red valves on the way to the main line. One says "reducing" and the other says "relief". So the cold water feed is already turned on but it doesn't seem to be working properly.

Is there any thing else I can try to get some more water back into the system? The pressure is reading zero so it must be very low.

I tried bleeding upstairs again and I heard a little air, but no water came out and not much air really. Seems like if I wait 1/2 hour I get a little pressure build up but nothing much, and no water yet upstairs.

Thanks for the feedback, Steve

[Stormin Mormon]

Should be more like 10 PSI in the system. Call a heating company out to repair it.