boiler problems, should we got to forced air

churchboard

I got elected board president at church in time for the boiler to act up again. The heat exchanger is out for like the 4th or 5th time in 4-5 years. Boiler is less than ten years old. Heat exchanger warranty has been denied due to bad water. There maybe a leak in at least one section of the system, Pipes are copper and under concrete and 40+ years old. One contractor has suggested that we should switch to propane forced air heat. Cost would be about 10,000 for new boiler, 15,000 for new boiler pumps etc., and about 25,000 for forced air for 3 furnaces and duct work. The furnaces could have air to air heat pumps added for about 4000 each. Thank you in advance for any suggestions I don't know much about furnaces and nothing about boilers.

Steamhead

Lots of questions here:

Is this a steam or hot-water system?

What boiler do you have now?

What, if any, problems do you have with the local water supply?

Where are you located?

Forced air will never work as well as a hot-water or steam system. Toss that contractor off your list.

And finally, we do not discuss pricing on this forum.

Harvey Ramer

When you say copper and under the concrete, do you mean you have radiant floor heating or are they distribution pipes? Do you know for certain that they leak or was that just a suggestion? Why not pressurize the system, get it up to temp and shut off the fill valve to see if the pressure drops? If it doesn't drop you don't have a leak. Is there any boiler protection installed? If there isn't and you are dumping cold return water from the slab into the boiler, it will eat heat exchangers for lunch. THAT is an easy low cost fix.

Post some pics and supply us with all the info we ask for. There are a lot of things to check and be done before making any big financial commitments.

churchboard

It is a hot water system, there is a boiler buddy, the copper pipes are for distribution, the water is very hard 25-28 grains, we are in west cental Iowa, the system is set up to add water when necessary and the water bill jumped up to 25,000 gallons one month until one section was shut off, but now it pressure tests ok. I am sorry if I wasn't supposed to include pricing, I thought it would be ok for comparison and not linked to a certain supplier. I should add we are a little gunshy about the hot water heat since we have so many problems with the current boiler and the church we share a pastor with had a hot water leak under their concrete that caused major stuctural problems. The brand of the heat exchanger is Triangle Tube I assume the boiler is the same, but I don't know. Also the pipes that come up out of the concrete don't look to be in very good shape, ther a lot of corrosion. Thanks again.

Snowmelt

I would see what it cost to convert to baseboard also.

Jamie Hall

Are the copper pipes under the concrete or in it? If they are in it -- or otherwise inaccessible -- you do have a problem. Otherwise, first thing to do is to find that leak and get it fixed -- and look at all the rest of the piping while you are at it.

Copper is usually not too bad about corrosion -- except in two situations: acidic water will eat it up, and so will heavily softened water. Hard water usually won't, although it won't help the heat exchanger any and you may need to run a descaling agent through it from time to time -- which can be as simple as vinegar in water (and then flush it back out again, please!).

Forced air heat (heresy coming here!) does have some advantages for a church, or other buildings with only occasional occupancy. It's not particularly comfortable, and it usually has air quality problems -- but it does recover heat rapidly, say on Sunday morning.

Gordy

It would be nice to have a water sample analysis done to see why the hxers were failing. That's a lot of failures in a very short period. The manufactors did not indicate what was suspect by chance did they?

You can treat the water to negate properties of the supply water. Controling ph, hardness etc. but it's not a one time walk away forever. It needs to be periodically checked, and maintained.

As for your dilemma. I would investigate a little more into why the boiler failed. Fix the leaks, and that will save quite a few toad skins verse doing a completely different system.

Larry_52

With that kind of hardness and unmonitored makeup you would need a treatment of the incoming water to make the boiler and piping last. You could chemically treat the system with sodium sulfite at 50ppm residual for O2 removal and raise then pH with caustic BUT I would not go above pH of 8.5 with copper. If the makeup is not pretreated this type of precipitate chemistry treatment can go after the copper pipes with pH above 9 and high TDS. If you stay with hydronic system, treating the incoming water is long term solution to failures. Deionizing followed by RO would be best, softening could work but still may get the TDS into the range that is aggressive on copper.

Gordy

I'm wondering if I'm understanding correctly. Is it the heat exchanger in the boiler that failed, or is the boiler supplying hot water to a seperate heat exchanger that is supplying heat to the church?

nicholas bonham-carter

In most hot water systems, the water is only added once, and therefore, only has a certain amount of calcium to gum up the boiler. If you have a leak in the system, then there will be constant addition of water, and oxygen, and calcium, and that is a problem.--NBC

Mark Eatherton

Check with your insurance company. You may have boiler replacement insurance. If not, find and eliminate ALL leaks, and replace the boiler and keep the hydronics. It is the most efficient way to heat and cool a building and is compatible with ALL alternative energy sources. Converting to forced air will increase your power bill as well. Hardness in water is not an issue in a good tight closed loop system. It's the continuous makeup due to hidden leaks that caused the problem. The hardness in the water actually provides some protection to the pipes and other metal components in the system to a point. It's when it makes up continually that it becomes problematic.

If your contractor needs help with leak identification, have HIM come here and this group can educate/orient him. We're here to help.

ME

nicholas bonham-carter

Were both churches' systems installed by the same person?
What do you have for air conditioning now?--NBC

Larry_52

nicholas bonham-carter said:

In most hot water systems, the water is only added once, and therefore, only has a certain amount of calcium to gum up the boiler. If you have a leak in the system, then there will be constant addition of water, and oxygen, and calcium, and that is a problem.--NBC

Totally agreed the scale corrosion should be a one time event that reaches equilibrium quickly as the system is closed. But based many outside influences and current reality that cause the uncontrolled makeup a deionizer will prevent longer term issues with little hands on maintenance. even then you would still need to take care of the O2 and further corrosion. Hence the residual sodium sulfite and pH treatment (maybe to much hands on). If the system is already compromised and you know all the pipes are not going to be replaced my opinion is to try and save what you have.