I have cast iron baseboard throughout my old home. There is a little valve with a screw on each section of the baseboard. I routinely bleed the air out of the system - most of the air accumulates in one section on the 2nd floor near where the water goes up. Lately, it seems that there is more rattling in the pipes. I have an oil fired Weil-McClain boiler with an expansion tank and no hot water heater.

Should I be adding water to the system as well as bleeding it?

How is water added if I need to add it?

Is there a proper way to bleed the radiators?

 

You should't have to routinely bleed air if your air removal device(s) are working properly. What type of expansion tank do you have - conventional steel tank or bladder type? If the latter, you need an air removal device, such as a Maid-O-Mist with the valve cap loose or off.

What is your system pressure, both hot and cold?

To fill the system, open the isolation valve ahead of the auto fill valve (located between the city water system and the boiler).

Best to open bleeders sequentially in the direction of flow.

 

Mike,
Thanks for your quick response. I am not sure but I think I have a steel expansion tank, it is at steel tank on top of the boiler. I just took a picture, but don't see a way to attach it here. I have a well with a pump in the basement (there is a name for this type of well, but I can't remember what it is). I'm not sure what you mean by hot and cold system pressure. Also, can you describe what the isolation valve looks like. Thanks Deb

 

Post the photos on one of the freebie hosting sites, and paste the link here. Google "free image hosting" and you'll find them.

The more photos the better. Include both closeups and wide angles.

There should be a pressure/temp gauge on the boiler. Tell us the pressure and temp with the boiler at normal operating temp and with the boiler cooled down to room temp, say less than 100 deg.

 

Ok - I hope this works:

Boiler pictures by uvm1978 - Photobucket

The temp setting on the furnace is 175 hi and 145 low - is that what you mean? It's registering now at about 150

 

There must be a pressure gauge too, possibly on the same dial as the temp gauge. Tell us what it reads along with the temp at the same time.

The blue tank is for your well water system. The horizontal steel tank is a conventional expansion tank for your hotwater boiler.

You have a copper-colored air eliminator with a red cap. With a conventional expansion tank, you don't want that. Tighten the red cap until it is convenient to remove the device. Or, keep the air eliminator and replace the conventional exp tank with a bladder type.

Please take some more photos of the rear of the boiler - I can't quit make out the fill-line arrangement.

 

air should not routinely collect.
yes,you do need to remove it by bleeding, as you are already doing) but you also need to figure out how it got in and fix the defect.

the entry of fresh water( to replace leaked out water) introduces dissolved air, in this new replacment water, Then when the boiler heats the water, the air escapes, collects, adn you vent it out. but this is not good, you don't want fresh oxygen always entering your system.

Is there a leak, that your auto fill replaces on its own?
Do you refill it on your own?

or is there another air entry location?

 

OK, here are more pictures: Boiler pictures by uvm1978 - Photobucket
If I am reading the right gauge, the pressure is around 10. The temp is close to 180, but then it's very cold here today so the furnace has been running quite a bit.

The red cap on the valve was very loose so I tightened it. It is stamped with a 2007 date, so it must of been something they added when they serviced it then. How much does a bladder tank cost?

Thanks so much for your help, I really appreciate it.

 

I have never added water to the system as I don't know how to do this. I am not sure if there is any other way air can get into the system. Nothing seems to be leaking, but I did just tighten the red cap on the valve as Mike suggested. It was almost off, very loose. Is there some way that water automatically is added to the system?

 

you may well have an auto fill device on your water supply. If it's adding water regularly, you will always be removing air.
but we still don't know why you keep needing more water.

first, the 10psi may be too low. How many stories high is your builing (distance, height, between boiler and highest radiator in the building)? too low a pressure invites air to be sucked in at the top radiator.

 

upon re reading your posts, 10 psi after the boiler has been running is too low, and i believe that is your problem.

I think you need to find where you water supply enters the boiler piping, and add more water
you want at least 15 psi when cold, andit willgo up a few more when heated up.
if you have a tall building, you will need even more

 

Is this a 2-storey house? But, in any case, 10 psi at 180 deg is too low a pressure.

For some reason, I can't identify the automatic fill valve in your pictures - but there has to be one. Possibly its shut-off valve is closed? Once I or somebody else here can identify the auto fill valve, we can tell you how to add water to the system and boost the pressure. (Low pressure can result in air being sucked into the system - either from atmosphere or from the expansion tank.)

Maybe you can help. There should be a pipe that connects the regular cold drinking water to the boiler. Find that pipe, and take photos all along that pipe so we can see what valving is installed.

Don't worry about the cost of a bladder tank (I wish I hadn't mentioned it). Your conventional tank probably is fine. But whoever installed that air eliminator two years ago - uhh, well, don't call him back.

We need to take one step at a time - the first is to get the pressure up to where it belongs.

 

Let's see where the pipes going to and from that bell shaped thing behind the boiler go to and from, and if there are shut off valves on that pipe.

What do those little tags hanging on the valves say?

 

Here are more pictures with notes:

Boiler pictures by uvm1978 - Photobucket

Check out the one that says cold water pipe from well to furnace

 

Here is the auto-feeder. Your note on the picture says "Mysterious gold valve behind furnace with screw on top" Is there a valve on the small line leading into this feeder? If so is it open. I would assume it is but the valve is not feeding.

 

The pipe that goes up from the auto feeder leads to the blue handled valve that says water - that valve is open. The pipe that leads the other way goes to those much larger diameter vertical pipes that are connected to the circulating pump. Should I try to adjust the screw on the auto feeder?

 

By the way - the house is a 2 story dutch cape. It's much smaller upstairs (due to slanted ceilings) and has no attic. Also, it's an old house so the ceilings are low and the house overall is not very tall. What is the correct pressure range for this type of house?

 

ther e are formulas you can get ( i dont have them, but i've seen them in this forum) to convert number of feet of height into psi needed,
but its at least 15 psi you willn eed when system is cold, and it will go up maybe another 5 or so when hot

 

12 psi when the boiler is cold. With it being hot since it is cold out you could bump the pressure to 15 psi for now (hot). Then when you get a chance to let it cool set the pressure to 12 psi (it will drop off as the boiler cools).

Al.

 

I am still not clear on how to increase the PSI to 12-15. Should I turn the screw on the gold pressure reducing valve? I checked a website and it looks like I should be turning it clockwise to increase the pressure. Would someone please confirm.

 

many pressure reducing valves have a bypass lever : you pull a metal lever up, adn then you get unregulated pressure water in, if you have that, pull it till pressure on guage rises.

or you may have a bypass pipe that allows water in without going thru the pressure reducing valve

 

The valve in the picture titled "Mysterious gold valve behind furnace with screw on top" looks to be the pressure reducing fill valve. You posted that the valve leading to it is open.

Try to add water/pressure by loosening the lock nut, then turning the screw in about 1/2 turn. See if that bumps the pressure up some. If it does then you can further adjust it for 12 psi.

If it doesn't change the system pressure then it is either the wrong valve or it is no longer operational (it's broken).

Al.

 

turning screw on press red. valve: cant hurt if you turn it wrong way. you will hear water flow if you turn it right way. nothing will happen if wrong way,
just try it.

 

I have been monitoring the pressure gauge all day and it seems to go from 8 (cold) to 13 (hot). This hasn't changed despite my increasing the setting on the pressure gauge.

 

I can't seem to find any other way to let water in. All valves are open and the auto fill screw is tightened just about as far as it can go.

There are 2 other gold gauges that look very similar to the one behind the furnace. They are up on the highest pipes on the other side of the furnace from the blue handled valves. They don't have screws, but instead have turn keys and they say SWETCHEK on them. What are these?

 

Boiler :: SWETCHEK valves picture by uvm1978 - Photobucket

 

I don't think those check valves are in the line between your domestic water and the PRV, are they? If not forget them.

OK, here is my $10 bet. Look at the PRV - chances are that on the bottom there is a threaded strainer. Turn off and cool down the boiler and drain system. (Isolate the well water supply to the PRV, too.) Unscrew the strainer nut. With well water, particularly, it could be plugged. If so, clean it out and replace the strainer.

 

That makes sense because my plumber was here recently and he mentioned that he would like to put in a water filter because there is a lot of sediment (iron, etc) in the water which is affecting the faucets and gaskets. It's probably the same thing with this valve. Well, I think draining down the system is a project for another day and maybe something that I don't want to try. Would it make sense to request this at the time of my next boiler tune-up? Will the low pressure harm anything in the meantime?

 

I can't predict exactly what harm would come of not correcting the low pressure before spring. But, I think it is preferable that the pressure be raised now. I understand your aversion to draining the system, though. So, I talked to my uncle, Mr. Rube Goldberg, who gave some ideas for you to consider.

You can temporarily hook up a garden-type hose between a hose bib on your well-water system and a hose bib on your boiler system. You'll need one section of hose that has female hose couplings on each end - like a washing machine hose. Throttle the inlet flow into the boiler and watch your boiler's pressure gauge. Do this only with your boiler cooled down to 100 deg or less to avoid thermally shocking the boiler. Get your pressure up to, say, 12 psi at 100 deg. Bleed air from your system again, and add more water if necessary if the system pressure drops below 12 psi after air bleeding.

Another idea: rap the PRV valve with a plastic or rubber mallet, or maybe a block of wood. Maybe that will loosen up anything clogging the strainer, and allow it to work again, even if briefly.

It's very possible that your PRV has an integral check valve that would prevent backflow from the boiler. If so, you could close the shutoff valve upstream of the PRV and remove the strainer nut without draining the system. Loosen the strainer nut to relieve pressure. If the flow subsides within about 10-15 seconds, you can then remove and clean the strainer. If the flow doesn't stop, then re-tighten the strainer nut.

 

If you have a washing machine nearby, so much the better, because you can unscrew the hose from the back of the machine and connect your garden hose to it.

Then, connect the other end of the garden hose to the boiler drain... here's the thing though...

That garden hose is full of AIR... so if you just screw the hose on, you will end up pumping all that air into your boiler. You don't need more air! So, figure some way to bleed the air from the hose first. You could do this by leaving the connection to the drain at the boiler loose... and turn on the water at the washer... tighten the hose when you get water... you will still be putting SOME air in, but not the entire hose full. If you happen to have one of those "Y" adapters for garden hoses, that would make a dandy bleeder valve... leave the boiler drain closed, and open both of the outlets... air will come out... when you get water, close the 'bleeder' outlet.

THEN, slowly open the boiler drain and let the water in a COOL BOILER ( under 100 degrees ) until you are at 12-15 PSI. Hint: if you are worried about 'shocking' the boiler, you can use the hot outlet for the washing machine.

 

Ok - I finally got around to getting a washing machine hose at the hardware store. I hooked it up to the cold water feed and the expansion tank. I added water until the pressure gauge read 20. Then I bled the air from the baseboards, turned on the furnace and bled them again. Now, everything seems to be working fine. The pressure gauge tops out at 22 and the pipes are not clanging as much. You guys are the best - this truly was a $10 fix.

 

Glad that's working for you! keep bleeding, because with the addition of the fresh water, over the next few days/weeks, the O2 in the water will come out and need to be bled.

At some point, when you are satisfied that you've gotten all the air out of the system, turn off the boiler and let it get cold. With the boiler cold, adjust the pressure to 12-15 PSI.

 

I have been keeping an eye on it all week and it seems to have settled at about 13 PSI cold - thanks again for your help. deb