By means of background:

I live in an old house with a 30+ year old oil boiler that works fine and also heats a 6 year old Weil-Mclean Gold Plus hot water tank. My internal plumbing seems to be all all upgraded and copper. My main supply in the house is 1" copper. The supply from the street is galvanized. I have lived here about 3 years.

Once in a while the new water in my toilets after flushing can be brown (about 4 or 5 times a year). And my room humidifiers build up an orange rusty residue. Also, my warm-mist humidfier builds up kind of a milky white sea-shell type coating on the metal heating reservior that needs to be chipped away.

The story:

About a month ago my water (city water) started smelling and tasting metallic and earthy. This was very sudden. The taste was also noticable, though reduced, through my under-sink water filter (a GE micron filter) that I have been using for 2 years. The water through the filter had previously always tasted fine and I had just changed the filter about a month prior.

I called the water company and they came out and ran some tests and told me that my water was within code.

Over the next few weeks my hot water started getting hotter, but I attributed this to the change in seasons (In the late fall I always need to start setting my faucets more towards hot. Then in the spring, I begin setting them more towards cold. I always thought this to be due to the varying temperature of the cold water supply getting mixed in.)

Then one day I was in my basement and noticed a puddle under my boilermate. I have an American Homeshield Warranty and a service plan with my oil company. I have had several service people out to the house and here are the details of each visit.

1. A plumber took a look at it. He bled the T&P valve into a bucket and it came out very rusty. He assessed that the water was way too hot and a check of the thermostat seemed to indicate that it was not functioning properly. His assessment was that (a) the thermostat was broken and (b) a possible pinhole in the coil was allowing boiler water to mix with the water supply in the tank. He speculated that the hole might be caused by particles in my water supply. He said the tank probably needed to be replaced. He looked over how everything was installed and said it was done correctly.

2. A heating/plumbing man listened to my story and explained that the coating that builds up in my humidifier from the mineral content in my water had probably built up a layer inside my hot water tank. He explained that the hot water supply to the house draws from very low in the tank and that the coating would have narrowed the space between the effective bottom of the tank and the intake. This would cause more undesirable particles from the bottom of the tank to get sucked up and come out with the hot water in through faucets. He said what I was experiencing was not boiler water. He also bled the T&P and said it did not contain boiler water. He said the tank needed to be replaced. He also looked over how everything was installed and said it was done correctly.

Now up to this point I still had hot water in my house-though too hot. But now it stopped all together. Also I had begun hearing a slow running water of unknown origin (like when you have a running toilet somewhere in your house). I checked the thermostat and rotated it to no effect.

3. A service tech from the oil company came out and I explained to him what the previous two people told me. He said the hole in the coil story was plausible (#1). He did not refute the coating of the interior of the tank story (#2). He said the water running noice might be the heating system replacing water lost through the boilermate (ostensibly through a hole in the coil). I asked him if I should just replace the thermostat, but he said it wouldn't be worth the money and that I should just replace the tank. He didn't actually inspect anything. He referred the oil company's sales department to me. We unplugged the thermostat connector cable all together to avoid a malfunction that would result in overheating.

Now I can make hot water when I need it by manually kicking in the boiler for 20 minutes or so to heat the tank. Then I have hot water for a few hours.

Three days ago (over a week from the first such event), I went back into the basement and there was a puddle under my boilermate again - ostensibly from the T&P release. However I had not run the boiler in many hours. I bled it again myself into a bucket and the water was clear - not rusty like the first time. I don't know what caused this puddle.

Then two nights ago, there was an early spring overnight temperature drop and my home heat kicked in to heat the house. The next day we had hot water almost all day without me having to manually start the boiler. I don't know how these things work, but I assume somehow that heating the house also heats the water by default, but without a thermostat how can this work properly?

I have argued with American Homeshield about coverage, am waiting for call back from the regional Weil-Mclean rep., have looked into water filtration and conditioning, spoken to multiple vendors about both replacing the boilermate or the thermostat. I have gotten prices on both.

I had Culligan out to do a water assessment and he told me my water was hard but not too bad (I scored a 6 or 7, whereas he said a 9 or 10 is usally the bad range).

Help:

Can anyone help me to decide whether to replace the thermostat for $200, or to replace the whole tank for $1000-$2200? Then, do I need a filter, a softener, a conditioner to protect my water appliances?

Thanks, Jeff

 

Before I got into the HVAC trade, I worked for 13 years in an environmental sciences lab where I tested water, so I know a bit about water. Here goes: The whiteish deposits is likely calcium &/or silicates. As far as the taste & discoloration, they probably had a water main break somewhere or maybe a major fire which caused a drop & then surge of water pressure thus breaking old deposits in the mains loose.
If the tank is installed according to the installation manual, your hot water comes off of the very top of the tank. http://www.weil-mclain.com/FTP/Water...ine_Manual.pdf

I would doubt a 6 year old tank would need replacing. To confirm the water on the floor is coming from the relief valve, pipe it down about a foot from the floor if not already done. This way you can put a bucket under it to catch any discharge from the relief valve. Water in bucket = from relief valve & possible bad thermostat. Water on floor but none in bucket = leak.
Measure the temperature of the domestic hot water. Without that information, it really is a guessing game.

 

Grady,

Thanks so much for taking the time to read and reply. It has helped me move closer to deciding that replacing the thermostat is a good idea.

Unfortunately I can't open the file at the link you supplied. My Adobe reports that the file is damaged. I have the original documentation for the unit, but can't seem to locate a citation on the depth of where the hot water is drawn from.

A few follow up questions in case you or anyone else have (has) a chance to provide any additional guidance. It would be greatly appreciated:

1. Would simply the overheating of the water (i.e. due to a bad thermostat) in the tank cause the T&P valve to release? Would it also bleed water out of the small air valve on top of the unit?

2. There is cakey green and white corrosion around the plumbing joints in and out of the tank. Is this indicative of anything suggesting the tank is bad? Is it something serious in its own right?

3. Could the water scenario you described, with deposits being broken loose in the mains, possibly "break" the water heater - either through puncturing the coil or causing damaging, irreperable build-up or particles in the tank?

4. How would I decided between whole house water filtration or softening? Is there a resource that describes various water contaminates, what they do (including to household plumbing and appliances) and how to remove them?

5. Is this kind of "Indirect" water heater or boilermate considered a "storage tank"? Are regular water heaters considered "storage tanks"? (My home warranty says it covers oil hot water heaters AND my boiler, but not "storage tanks". However it does not define "storage tank". I am wondering if there is an accepted definition in the industrial lingo.)

Thanks!
Jeff

 

I'll try to answer your questions in order & to the best of my ability.

1. It certainly would cause a release of water thru the relief valve. Maybe from the air vent.

2. It is not a sign of a bad tank. It is corrosion from either a sloppy installation, the use of incorrect fittings, or a leak.

3. HIGHLY unlikely particulate matter coming in from the street to puncture your Boilermate. It certainly could cause particulates to be in the tank. How much harm would come from that would depend on how much junk was in the tank.

4. Your best bet, although I'm sure the infomation is available on the web, would be to talk to someone at your water company or local health dept. Personally, I would start with filtration.

5. The term storage tank implys there is no internal means of heating the water, only storing the water once it is heated. Your Boilermate actually heats the water. Maybe this will give you some ammunition in the argument with the home warranty company, but don't expect to win.

For a diagram of from where the hot domestic water is drawn, see the piping diagrams on pages 7-10 of your manual.