System leaking but no signs of water.

Nick W

My home hot water heating system has begun losing water, but I can't find any water around the boiler or the copper loop system. ME will shake his head and chew me out for still having my 1965 Hydrotherm boiler, but that's what I have.



I have looked for leaks around the boiler when hot and when stone cold. I have checked the accessible joints on every finned-tube radiator and have checked the drywalled basement ceiling for signs of leaks. No pipes are in concrete. No signs of water anywhere.



I estimate the system holds about 17 gallons. It has a #15 diaphragm expansion tank. The pressure drops about 4 pounds in 24 hours, which I figure amounts to 2-3 cups of leakage. I don't think the PRV works, and so I refill manually to 13 psi cold or 22 psi with both zones fully hot. In the past I have had to add that much water only once a year.



Is it likely that the boiler could be leaking that much without water showing underneath?



Any suggestions?

Steamhead

Sure is

you may have a leak at the boiler, which might only be leaking when it gets hot. If the leak is inside, the water will go up the chimney as steam. If there's enough steam you'll see white "smoke" billowing out the chimney.



Do your heat-loss calculation. My guess is you'll need it soon.

Nick W

Thanks,

Steamhead. I sure hope it is the boiler rather than a pipe in a wall or ceiling. Unfortunately I'm in the Denver suburbs where it is cold and getting colder, making the chimney "steam" whenever the boiler runs -- 22F this afternoon and 7F tonight.



I have a load calc that I did with Right-Suite -- 38,400 Btus at 0F. But we want more Btus for hot water. My wife likes long, hot showers, and I will never hear the end of it if a new boiler won't deliver what she is used to. The Buderus indirect is only 39.6 gals and is rated for 119,000 Btus. The Hydrotherm is rated at 145,000 Btus input, but runs on 820 Btu gas. Please don't call the Green Police on me!

Steamhead

Well, here's one solution

Burnham ES-23 and Triangle Tube 40-gallon indirect. Heat loss was about the same as yours. Go here:



http://www.heatinghelp.com/forum-thread/129307/Our-first-Burnham-ES-2-Install

Alan (California Radiant) Forbes

Water loss

Have you checked the relief valve drain?  If the expansion tank is compromised, you will get the symptom of loosing water during operation.

Nick W

Relief valve and tank seem OK

No water has come out of the relief valve since I popped it by mistake a few years ago thinking (without looking) that it was the fast-fill PRV. Dumb move.



The expansion tank seems OK, but it is 15 years old.



One clue is that my hand comes out very damp when I stick it up into the draft hood when the boiler is firing. That may just be normal, as it's been a long time since I've done that.



Thanks, Alan, for your help.

Mark Eatherton

I am shaking my head Nick.....

Up and down. NOT side to side. It sounds like it is PAST time to replace your lovely hunk of cast iron. It has exceeded the normal life expectancy for a conventional cast iron boiler.



Call my good friend Jim French at AHI and have him set you up with a good Knight wall hung boiler. It is compatible with the Buderus tank. A 50K btuH heater will deliver around 88 gallons for the first hour. A 2-1/2 gallon per minute shower head would require about 2 GPM of hot water per minute, so she could take a 44 minute shower without running out of hot water.



I have a 50K btuH modcon that goes up to 80K for DHW calls, and I can not run my system out of hot water.



TIme to bite the bullet pal, and trust me, you will not regret it. There are some tax credits available to help make it worth while. Oh, and did I mention that you will reduce your energy consumption by a minimum of 30%?



ME

Nick W

Deleted as off topic.

Nick W

Boiler is not leaking

A thorough inspection of the boiler by a NATE certified technician disclosed no signs of leaks. So now I guess I just keep looking for signs of water or moisture around the house.



It's probably unwise to replace the boiler until the leak can be found and fixed. Unfortunately the basement ceiling is finished and the basement floor is carpeted, making it difficult to find a small leak. Fortunately the walls don't contain any mold food (OSB).



Any suggestions for finding the leak are most welcome.

Big Ed_4

Leak Check

Pour a little Spearmint oil into your boiler water , then follow your nose ....

Nick W

What a great birthday present!

This morning -- my 71st birthday -- I raised the pressure in the boiler to 22 psi when it was fully hot, and water began to drip onto the floor - one drop every 5 seconds or so.What a relief. Now I won't have to stink up the house with spearmint oil -- just have someone put in a new boiler.

Constantin

Happy Birthday!

Good News, I guess... a leak at the boiler is easier to fix than a rotten pipe in the wall. If you live in a cold climate, I second the call for a nice mod-con boiler that can ramp up and down as needed. While you're at it, consider adding variable-speed circulators if the local conditions are good for them. And definitely get a new expansion tank. 15 years is asking for it, IMO.



Cheers! C.

Nick W

Simple house = simple system

ME has been after me for a several years now to replace my 1965 gas HydroTherm with a mod-con. But IMHO this 2,500 sf house really is not worth it, and I can't justify the additional cost and expected maintenance expense.



My annual gas bill, less the fixed monthly charge, has averaged only $888 for the past 5 years. The high 12-months was $984; the low, $768. Winter comfort is not a problem for us.



If I put in an 82% efficient natural draft boiler and my present one is 65% efficient, I will save in theory about $185 a year in fuel expense. If I put in a 95% efficient mod-con for quite a bit more money, I will save in theory about an additional $95 in annual fuel expense.



A natural draft boiler with a standing pilot should require minimal maintenance. The mod-con will require more maintenance expense that it saves. At the moment I am thinking about a Slant/Fin Sentinel as it will fit very well into the available space and has excellent AFUE with a standing pilot. We are well equipped with CO alarms.

Mark Eatherton

I guess you gotta do what you gotta do....

Nick, It is your money, and you are driving the bus.



For me and my money, I don't look at the economics as much as I do my reduction in carbon output, and the best way to do that is to go mod con, but not everyone can afford it.



No sure where you are pulling your reduction numbers from, but suspect you are trying to compare apples to pipes, which doesn't work with gas fired appliances, unless both appliances are in the same laboratory settings.



If everything this industry does was based purely on economics, there would never be another modcon boiler, ground source heat pump or solar thermal system sold. Fortunately, such is not the case.



One thing for certain, you need a new heat source, whatever it is.



Happy Birthday



ME