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[lindnova]

I have a 7 year old Heatmor 200 that has operated with no problems.  It started making a hammering noise this year when firing hot with a full load of wood.  I turned down the thermostat to 178 thinking it was getting too hot.  I checked the anode rod - it is mostly gone, but not rattling around.  The heat shield (I am about ready to just remove it) is not moving.   The noise seems to be coming from inside the front of the water jacket where the exhaust starts up the flue.  It is getting bad enough for concern and actually causes the thermostat to move out of its slot (it is a cheap plug - not a screw in one).

I use soft water and did drain and flush it 3 years ago without too much sediment.  I flushed it mainly because I was switching to a different type of treatment chemical.  I think the anode rod contributes most of the sediment.  I replaced it once, but not sure whether to replace it now or not.  The nitrites and ph are normal with Central Boiler chemical.  I do have a Y strainer and don't get much in it.

Any ideas?  I am concerned that if there is cavitation it could ruin the stainless steel jacket.  Could this be a scale problem?

[RSI]

How often do you have to add water?
Let the fire burn down pretty good and look around inside for a clean or wet spot. It sounds like you have a crack in the firebox. It may be clean around the crack because it gets steam clean from the water.

With a small crack like that, the water usually boils away before it gets to the bottom so you don't see it.

[fryedaddy]

Are there any water tubes in the top of your firebox?

The type of stove I have has 2-3" tubes in the top of the firebox. If the fire gets
hot enough you can hear steam blowing out of the tubes into the water jacket.

Kind of sounds like hammering but you hear the water rolling out of the tubes afterwards

[fireboss]

what is a anode rode ? 

[lindnova]

Thanks for the replies! 

I don't have any tubes in mine.  There is a firebox with a square flue above it where the gas enters one side of the flue and exits up the chimney on the other side.

Shortly after the first time I heard the noise I topped up about 4 gallons - that was the first week of January.  That was the only water I have added in the last year.  I was concerned about a leak then, but 2 months later it is still full, so I wasn't worried about a leak.  I will check for leaks still as it makes sense that it could be a leak. 

The anode rod is a magnesium rod designed to be sacrificial and corrode instead of the steel tank.

[RSI]

Have you tried calling Heatmor to see if they have any ideas? It could be something to do with their design. If it is, they have probably seen it happen before and would know the cause.

[XJCraver]

Hmmmmmmm.........

My Empyre is only two weeks old, and working perfectly.  Since the initial fill, I haven't added an ounce of water and it has stayed at the exact same level.  EVERY time I load it, I can hear the stove... thumping?  I wouldn't call it "hammering", it's not that loud, but it is definately an audible thumping noise from all over the water jacket.  No change in the sound if you listen from the front of the stove, or the back. 

I just figured it was the nature of the stainless box, and it would always make noise?? 

[lindnova]

Thumping would be a good term for it.  The only thing with mine is it used to just make a hissing "steaming" noise when firing.

I did look through the fire box good tonight and it is farely clean with a light coat of creosote and some heavier areas, but pretty even throughout.  There is a lot of dry ash at the flue opening.  I will clean it out good this weekend.  I usually clean the flue box about once a month.

[MD20/20]

I've had that sound as well occasionally.  Usually right before it's up to temp.

[Scott7m]

If it's after a long burn it can be a boiling spot in the water jacket...  But the heatmor, could be the bladder

As far as the empyre, I have no idea,I've never heard of it in them but have heard it before in other brand. 

[XJCraver]

It's not loud at all, and I'm not the least bit worried about it.  Just thought I'd throw it out there for him, let him know his isn't the only one that makes a little noise.   

[mag1266]

Check for blockage in the water lines to the door. probably at the fittings.

[oldchenowth]

Just a thought here.  What speed is your pump set at?  I have a three speed, and if the water isn't flowing at full speed, it hammers in the tank.  I thought mine was going to explode the first time I heard it, but it was just boiling in a certain area(s) near the top of the tank.

As I said, just a thought.

[lindnova]

"Just a thought here.  What speed is your pump set at?  I have a three speed, and if the water isn't flowing at full speed, it hammers in the tank.  I thought mine was going to explode the first time I heard it, but it was just boiling in a certain area(s) near the top of the tank."

I have a one speed Taco 011.  That is interesting since my pump is 5 years old still quiet and working as far as I can tell, but maybe it is getting slower.  My first pump lasted one year and seized.  I have a spare one ready to bolt in - I know there are rebuild cartridges.  I learned that after I got the backup pump.  If I had to do it over I would have got a 3 speed Grundfos.

"Check for blockage in the water lines to the door. probably at the fittings."

I changed the hoses last fall and water sprayed me pretty good, but that is something to check since sediment would easily get stuck in the door.

Thanks for the replies.  I am now looking for a circulation problem, whether it be the pump, or sediment restricting somewhere.  I am thinking about draining and flushing when it gets warmer outside and I can shut it down for a day.  I know when I had it drained before I flushed the remnants of the anode rod out. 

[hoardac]

Had the same problem this winter, cleaned out my filter screen and that was not it so, I replaced the pump with my spare one and that took away the problem. Pump was 7or 8 years old and had some corrosion build up in the housing figured that was stopping the flow enough to allow the water to turn to steam, against the firebox wall, which will make a hammering sound. The pump was cast iron, not brass I guess Wood Doctor saved a little money when they built the stove.