Question about a gravity hot water heating system.

Brad White_9

Sounds like a full plate, Karen. I imagine a few of us will take a stab at it.
You might also check out the Find a Professional tab for someone in your area.

First, some general information if you do not mind:

Where are you located, geographically?

Is the house insulated? Roof? Walls? Both? Windows are of what type? Single pane with storms? Replacements? Just trying to get a handle on heat loss.

It is not surprising that first floor radiators do not heat as well than upper floors. Gravity hot water, if indeed that is what you have, tends to heat upper floors faster due to a stack effect. (I would think that your house was gravity HW originally. In 1919 that would be the standard for water systems. Forced hot water did not come into vogue until about 1928).

Water would not travel well laterally when it has an express elevator you can see.

The pump quite possibly is messing up the original intent, but to be sure, the system should be surveyed, make sure the basic original design is there.

The radiators, to assess them we would need more information, how many tubes, how high and wide each section is and how far apart they are center to center. The type of tube (oval or round) also plays a role. Any manufacturer's name in the castings are a boon.

Anyway, just a few thoughts on which to ruminate... sorry to be generic, but wanted to get you going with a response leading to hope...

Best,
Brad

Karen_9

Gravity hot water heating system

Ok, let me start by saying I live in an old house built in 1919 and I know very little about my heating system, and finding someone who does has been my dilemma. I am in dire need of some answers. It would appear, from reading over your site, that I have a gravity hot water system. What's throwing me is that I also have a pump and that wasn't mentioned in the overview on gravity systems. Perhaps that was added later. My house has 3 full floors, approx. 30' - 35' total height, with an expansion tank on the third floor, and the boiler psi is at 20 (which seems correct). My gas bills for Dec and Jan have been $500 for a very chilly house, so I'm trying to figure out how to improve the heat circulation without the last resort of buying a new boiler and or pump. I have a total of seven cast iron radiators in the house which is about 2800 sq ft. Of the seven, 5 are about 2' X 5'. The other two are considerably smaller. I've noticed that some of the radiators get very hot consistently, while others (in the 1st and 2nd floor rooms farthest away from the boiler-coincidence?!) only rarely get hot. One bedroom is an oven and the other, a refrigerated meat locker. In trying to figure things out, I've been bleeding all of the radiators pretty regularly and have found no rhyme or reason as to how this system is working. For instance, the hottest radiator (a newer smaller one)bleeds hot water right off the bat and is only 4' from a cold radiator that bleeds cold water right off the bat, not air. Several other nicely hot ones bleed nothing, no air, no water. The coldest one bleeds air and then nothing. I can't tell if this is an air or a flow problem. Am I experiencing the "phantom" air problems you mentioned, in which case I should just drain the whole damn thing and start over filling the first, close the vents, then fil the second floor, etc as you suggested, until the expansion tank is 1/3 full? Or is this possibly pump related? I've noticed that, after I run around bleeding air and sometimes water from the radiators, that I will hear water clunking it's way down from the expansion tank into the radiator in my 2nd floor bedroom. Any suggestions on how to resolve these issues would be welcome. Do you need more information? Be gentle, I'm single and not dating a handy man. Thanks!

clammy

things to check

Well if you have apump then you should not have a open expansion tank in the attic if i understand you correctly ?I would check all the raditor hand valves and make sure they are open ,check the water pressure that is in the boiler at least 12 psi on the gauge on the boiler then i would check the aquasta and see what it is set at .Maybe you do not have a pump and because of time and gunk building up in the piping it may be time to have a professinal come and install one and check out your system completly .Make sure that the person or company that comes are fimalar with gravity hot water systems and if still in doubt try the find a pro listing on the left these guys all know there stuff and are true steam and hot water system gurus that know how to get older systems of all types up and running as they should be .Peace and good luck clammy

Mike T., Swampeast MO

It sounds to me like you have a half-**** gravity conversion with some similarly poor changes to the radiation. It also sounds like you've done quite a bit of homework to understand your system.

You have a tank up at the highest level, right? You even hear water coming from/to it on occasion, correct?

Is there also a tank down in the basement near the boiler (it's usually hanging between the ground floor joists)?

No tank in the basement and with a circulating pump is what makes me say "half-****" gravity conversion. With only the expansion tank up high (BRAVO for using the right word) your converted gravity system is still open to the atmosphere. When a circulating pump is added the expansion tank is removed. A compression tank is added near the boiler. This results in a sealed system as it is no longer open to the atmosphere. Systems with circulating pumps need to operate in a sealed environment as opposed to open to the atmosphere.

Provided your pressure gauge is reasonably accurate, the system should have sufficient pressure--this is doubly evidenced by your high expansion tank being about 1/3 filled with water.

Something that seems troubling is that you open a bleeder on some rads and get nothing--neither air nor water. It sounds like the air bleed may be clogged with paint. Have a bucket and towels handy--keep opening the bleeder. The thing you turn is a simple needle valve--keep opening and it will come out. It should pop out with a rush of air or water--thus the need for the bucket/towels but you'll be able to replace the needle easily. In the extremely unusual circumstance that neither air nor water come out with the needle removed you need to drain the system, remove the entire bleeder (easy) and either clean or replace. To clean, remove the needle and boil it and the body in water for 20 minutes or so. Remove the bodies and blow through them as soon as they're cool enough to handle.