Weil McLain boiler problems.

[Pyle]

Hi all,

I am seeking an answer on a issue I am having with my boiler furnace. The heating unit is about 12 years old and has worked fine until I had a Plumbing and Heating service tech work on it a few years back. It has a cast iron tank, and is natural gas fired.

About 2 to 3 years ago I had a service tech just do a check up on the boiler, well he told me that the system needed drained and fresh water put back in, so me not being to bright about what would happen told him to go ahead and do it. At about mid winter out furnace started to sound like a coffe maker, we have all low profile baseboard heat and 1 inch copper lines. Then we started to get air in the system soon after the the noise started on the boiler. We road it out for the remainder of the heating season and made plans to have the service tech take a look in the spring. His advice was to flush the system again and bleed the air out or put a new boiler in, which he suggested would cure it, he said our boiler is old. So I did the water change again on his instructions. Well the next winter brought more noise from the boiler and air in the lines, bled off air out of the baseboards and boiler, it seemed like all winter that year, the noise was just terrible.

I ended up contacting another service tech about the problem and he took a look at the boiler and explained that it was limed up do to to much fresh water being added. He inspected for leaks and did notice the high preasure releif valve was dripping which could have lead to the lime build up in the tank. He gave me instructions on how to delime the boiler, but was not real clear on some of the instruction. He said use muratic acid 50/50 mix, close the input and out put of the feed lines and drain boiler and fill with mixture of acid. I did do this and what a stinky mess it made. I did rinse the boiler tank several times and then drained the whole system again and refilled with 50/50 of water and automotive grade antifreeze, which I just found out is a " big no no'' for the weil McLain boilers from the manufacture. We got through most of the winter with no noise problems or air in the system, but it started up again at the end of the heating season. I called both tech, and they are eager to just install a new boiler. I would rather delime the unit again, and we are having a water softener installed this week, so we have soft water in the boiler, our water is very nasty anyway, I know this will help the boiler from liming up again. And from what I have learned, the 2 service tech pretty much did everything they could to help it lime up. Below are a list of question I really need answered and help with, going to try this myself again.

1. Should I use muratic acid to clean it, and what ratio should I use?

2. How long should I let the acid sit in the boiler before I dump it?

3. How many times should I rinse the boiler after delime work is done?

4. Should I run just straight water in the system or put in a additive?

5. Will the soft water prevent the lime build up?

The sytem is a sealed closed loop system which when operating right gets no air unless you have a leak in a line I have inspected for leakes several times this year and found none. But if tank is limed up, the deposits will produce bubbles when boiler gets up to temp, just like a pan on the stove boiling, hot spots in other words. My boiler temp is set on 170 degree's.

From other things I have learned that antifreeze in the system mixed with water will walk when it is heated so to speak and cause's foaming at the pump, which in turn will lead to air bubbles later. The auto bleeder is working fine on the boiler. It spips water every now and then with air bubbles in it. I really need some advice from someone.

[jadnashua]

Once you get the air out of the system, unless there are leaks, you should never have to add any again. The system pressure must be within the specified range for the boiler. If it peaks too much, then you need to add water, the expansion tank is probably shot. The amount of minerals in what is probably less than 30-gallons or so of water should not require deliming, or if it does, not very often. You just can't disolve that much. Now, if it is constantly refilling because there are leaks, then yes, it could be a significant problem.

A new boiler is likely to be more efficient, so you'd have to do a cost analysis to see how long the payback period would be. There are often rebates from the utility company and possibly the feds if you buy one that qualifies, so take that into consideration.

Unless the system has loops that go outside, typically you don't need antifreeze in it (unless you turn the heat off for extended times in the winter). Adding antifreeze decreases the efficiency of heat transfer, so your boiler needs to be bigger or run longer to transfer the same amount of heat to your house.

I'll defer to the pros for your other questions....

[nhmaster]

In 36 years I have never de-limed a cast iron boiler. Shut the water feed off. Drain the pressure off, not the whole system. Replace the air vent that should be on top of the air scoop. Turn the wter back on. Run the system for a bit. Next look at the high limit when the boiler is at max operating temperature. If the temp gauge is above 200, turn the limit down to 180 or 190. If the boiler is running hot it will make steam and the resultant air problem.

Soluting # 3 Find a service tech that isn't a moron.

[Pyle]

Thanks for the response guys, I'm just up in arms over this whole deal. First off, our water here where I live is really nasty. About every 2 weeks I have to clean the shower head do to lime build up. I never really had any problems with this system until the first service tech told me to dump the water out of the system. We did not have a water softener at the time when we refilled.

As far as leaks go I did check several times to see if something was leaking, even pumped up the expansion tank to about 18 pounds with the whole system filled, and let it set a month this summer. It never lost more than a pound or 2 of preasure. I am costantly bleeding it though at least 2 time a week since heating season started. After softener is installed this week, I will completely drain the system and rinse it really good to get all the anti freeze out. I will hold off on doing the acid clean for now though.

As far as buying a new furnace, I want to hold off on that. This unit is only 15 years old, and was expensive. From info I have gathered this year, if the boiler is limed up this would cause hot spots, which inturn produce gas which is steam. This inturn produces air if I am not mistaken. and since there is antifreeze in the system right now, this would or could be walked which cause foam, and air bubbles.

The system is a closed loop system, with a tank fill of about maybe 2 to 3 gallons. Cold preasure is about 10 pounds, hot preasure at peak temp "180" is at 22 pounds. Expansion tank preasure is set at 12 pounds cold fill.

I did a test tonite and turned the boiler temp to almost 200, noise was even worse, and more air seemed to be in different rooms now.

If I should delime the tank, what would be the ratio needed, and how long should it sit before being dumped and rinsed.

[jadnashua]

Regardless of your water quality, it should never need to be delimed. You should not need to add any water. Since you do regularly, there is a leak. With the antifreeze and the pressure, it should probably boil at 240 or higher (the pressure raises the boiling point), depending on the actual pressure and antifreeze percentage. IF the circulator isn't working well, the water can stay too long in the boiler and it could get too hot. If the pressure is proper and the water is being circulated, even with some hot spots, it should not make those noises. If there is a valve that isn't fully opened, it could restrict the flow and allow it to boil.

You need to find the leak. You have one or you wouldn't need to add water.

You aren't sitting on top of a mountain are you? That lowers the boiling point and could be part of the problem. The water pressure should compensate, though.

[Pyle]

Jim,

I thank you for your replys they are helpful to a point, but you keep saying there is a leak. There was a few years back when the high preasure releif valve was dripping. This valve is like ones one a water heater when you buy one. This valve did not start leanking and was not noticed leaking do to the way it was put into the drain in the floor. The way I caught it was by a service tech when he undid the pipe to the valve. It was about one drip of water every 3 minutes. Which could mean a couple of gallons every 2 days or so, that was the only leak I had, and it was taken care of about 2 years ago, and I check this quite often. As I stated earlier I never had any problems with the boiler until we dumped the system and added fresh water. The first winter was ok until noise started late into heating season, and discovered releif valve leak was part of the problem that winter of 2005. The next fall in 2006 I delimed the boiler with the acid, nasty job to do by the way! I ran the waste water and acid threw a old bath towel into a bucket, and it looked like sand was in it, at least a cup or so of it. After I got done rinsing, I flushed out the lines had a tech come and fill system with 50/50 anti freeze, and it was ok for most of the winter, then the noises came back. It sounds like an old water heater thats 40 years old clicking and bumping, but the gurgling is terrible. And the surging at the boiler wich sounds like air trying to pass through the pump, I'm told this is foaming going on.

I did get intouch with the original installer this evening on the phone, he's retired but told me that it should have been filled with soft water like it was in the beginning. He did say that the releif valve leaking was a bad thing because it kept adding water which will create lime aka hot spots when fired up. He told me that I never did get it delimed very good and said that the 50/50 should not be in there, that it can foam in hot spots and walk through the pump fins. then turns into bubbles.

The boiler is the same as is was last year, same noises and sounds. Ive only done an acid clean once and am ready for another, and as I said our water is terrible here in this little town I live in, not fit to drink.

If I had a leak in it, why would it hold pressure for a month with the water feed shut off? The 2 service tech's, keep saying I need a new furnace, and will not give me advice on deliming it. I know its limed up just by the way its acting and the techs agree, but don't want to help me out with the use or best way to delime it. As I said our new softner will be installed this week, so soft water with "no" antifreeze is going to be used in replinshing, just clean soft water.

I should have never dumped the water in the sytem, and this would have never happened, but whats done is done. I just found out today also a home owner down the street has the same problem I have, but his furnace is really old though. Our water lines here in this little town are 90 years plus old, so all the junk and stuff ends up in our sinks and tubs, looks like pond water some days.

Whats the best way to delime the boiler and keep this from happening again??????????????????????

[nhmaster]

Turn the limit down to 180 to start with. The expansion tank should have about 15lbs of air in it if it's a diaphram tank. Pressure should not vary more than a couple pounds between hot and cold. If it does the expansion tank is bad. Forget de-liming it's a waste of time.