Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Need help troubleshooting my Dampp Chaser system

Thanks Wayne. That's good information. That helps my troubleshooting.

try installing the remote senor in the upper portion of the piano

I didn't feel that the regular Dampchaser installation for my Charles Walter console was enough. I added a back system and now the tuning is rock solid. I have a wood stove two rooms away.

Something you could try is plugging an old dial clock into the heater bar outlet of the humidistat with an “octopus” so the heater bar will still work. This will tell you how often it is calling for heat. I understand that it is made to cycle the heat on occasionally in order to circulate the air in the piano. But if it never comes on for long, then the one humidifier tank may not be enough. Another can be added. Consider bringing this up with the folks at Dampchaser.

Here's the update...

-My piano is slipping out of tune from a recent tuning. This may be for other reasons, but it is important for those who think that if the piano is holding its pitch it doesn't matter what the RH% readings are.

-DC sent me another humidistat to try. It's been installed for a day and it is no better. (The room RH% = 22-23%. Inside the piano, the RH% is 26-30%.) Also note that the room is very stable in temperature. It's been a couple weeks and I still haven't had to fill the water tank.

-Just for good measure, I changed the pads.

So I'm bummed because I was hoping the humidistat was the problem. Now I'm thinking 1 of 3 possibilities.
1) The humidifier is faulty. (water tank/ pads/ heater wires)
2) DC systems really don't work as well as people think they do and the claim of maintaining a RH% in the range of 38% to 45% exagerated or only seen in perfect lab conditions.
3) Some other reason I'm not seeing.

Anyone have any thoughts?

I doubt it's the humidifier. Earlier in the thread, you mentioned the pads were wet and slightly warm; that sounds like it's functioning normally. The humidifier is only 8w, so it won't get nearly as warm as the dehumidifier rods.

Thanks Loren. That was one of my questions... the humidifier bar is warm but not hot. I'm stumped. I've read some posts where people have measured the effectiveness and the system was swinging from 38% - 53% back and forth every 18 minutes. I would also think the system would work better on a vertical piano because it is a closed box.

The 22% room humidity sounds quite low. Let me throw a few questions at you to get a better understanding of the piano and its environment:

What brand is the piano? Size of piano? Age of piano?

What is the heat source for the room? How far away from the heat source is the piano?

Does direct sunlight hit the piano at any point during the day?

From where inside the piano are you measuring the humidity?

It is a 45" Walter Studio that is about 13 years old. The piano is in a finished basement in Massachusetts with baseboard hot water heat. There is no heat directly behind the piano. No sunlight at any point during the day.

I have a fairly expensive hygrometer that is accurate and certified to +/-2% and it is velcroed directly on the humidistat. I've also taken measurements on the bottom of the piano next to the water tank and got the same reading.

If you can, try putting the hygrometer higher up inside the piano.

Is there a plastic baffle installed above the humidifier tank (probably attached to the underside of the key bed)?

What is the wattage of the dehumidifier bar (the bar from which the humidistat hangs). It will be either 50W or 25W. You'll probably have to shine a flashlight on either side of the dehumidifier bar to find the wattage (I think it's on the side with the cord). It's imprinted on the bar, along with the Dampp Chaser name, and a date of manufacture. Depending on how the bar was installed, it may even be facing the back of the piano, so you might need a mirror to read the info.

Does the water tank sit directly on the floor of the piano, or is it hanging?

Just looked at the clock, and it's way past bedtime! I'll check back tomorrow...I'm just wondering how the dehumidifier and humidistat are reacting with each other, which will make a difference as to how often the humidifier turns on.

If you can post a photo of the installation, that might be helpful, too.

Note: I'm not a tech, just a piano "enthusiast"...

What was the RH at the time the piano was tuned?

22% RH is really low... Perhaps the system can't add 20% RH so easily (though you observed a 10% increase previously).

The RH in my home ranges from mid 30% to high 50% year-round (note: the seasonal humidity swings in the upper Midwest are seriously extreme, and would be worse without the use of a room humidifier in winter). My DC system keeps the piano in a happy enough state that I only need to have it tuned twice a year, and I'm pretty picky. In the dead of winter when things are driest, I may have to refill every 12 days.

At my work, 22% RH is (unfortunately for the pianos) the norm in my office in winter, with some sort of humidifier allegedly running in the HVAC system in my building. The pianos in the studio need tuning monthly, and it's not due to overuse... WIth the seasonal extremes and no real protection, both my pianos at work have suffered problems they had no business having at a very young age.

Should we be fortunate enough to purchase new instruments in the future, I will insist on a full DC system with an undercover as part of the purchase. Maybe the backcover would be a good idea for you, since your basement is very dry?

I agree with Mr. Gloo,

You need to get that hygrometer off the bottom of the piano. There is no way you're going to get an accurate reading there, even if it's right next to the tank: the warm, moist air goes up.

Another thing, though unlikely, would be to see if the tech installed a "dry" humidistat. Dampp-Chaser offers three calibrations: dry, normal, and wet. Some parts of the country are normally drier or more humid than others. Rather than have one part of the stat constantly in an attempt to reach a desired goal, these stats are calibrated to allow easier cycling between humidify and dehumidify, which is the way the system is intended to operate. The dry, standard, and wet stats are calibrated at 39%, 45%, and 51% RH respectively.

Regarding the placement of the hygrometer. My logic was this...the role of the humidistat is to sense the humidity level and turn on/off the humidifer/dehumidifier as needed. So, the humidistat is where the DC reading is being measured. Therefore, the hygrometer at that location makes sense. Unfortunatly, there are no other places higher up in the pinao to put a hygrometer easily.

dcb:

I have been following this topic closely. I don't remember any mention of the condition of the pads. Have they been replaced recently? Are they folded over long-wise to double thickness? I think they work better if they are not folded over like that. It seems that they insulate themselves and do not evaporate as much water. It is something you could try that certainly won’t hurt. Also, since you are carefully monitoring the humidity, you could try plugging the humidifier directly into an extension cord, bypassing the humidistat. This helps isolate the problem. But I would make one change at a time and observe it for an entire week before drawing any conclusions. Pianos can absorb and release a lot of moisture, but it takes a while.

dcb,

The components within the humidistat generate some heat, which could throw off your reading. The sensor within the H5 is located in the upper right corner of the box and airflow of the other warm components has been taken into consideration.

Why can't you mount your probe to the underside of the keybed, as close as possible to the strings?

Also, try plugging in and electric, motorized clock to the humidifier outlet, with a cube tap. Set the clock to 12:00 and check it in a few hours. It should advance by the same amount of time, if the humidity is really that low.

Jeff...great suggestions thanks. The pads are brand new...I just replaced them and I'm using distilled water to avoid the mineral build-up. The pads are doubled over. I think I'll try unfolding them (and cutting them in half lenghthwise) and seeing if that makes any difference.

Great idea about bypassing the humidistat. I wish Dampp Chaser would have told me to do that. I doubt it is the problem because I'm on my second humidistat. If it works, that would mean both the first and second humidistat were faulty. Not likely, but possible and a great way to rule it out.

Everytime I've gone into the piano and checked the pads, they were slightly warm so my guess is that it is working as best it can but it just can't humidfy enough to get the % above 26-30%.

Thanks for the help.

Jerry...interesting thoughts. My hygrometer has a temperature sensor as well and the temp inside the piano is consistently the same or maybe 1 or 2 degrees warmer than outside the piano so that small of a range shouldn't make too much difference.

I'm going to try bypassing the humidistat to see how much I can increase the RH%.

dcb:

Hope it works. We have the same piano and similar weather. My solution was to first put a second humidifier in the bottom of the piano, which helped a lot. Then a complete back system (in addition to the inside system with just one humidifier), that did the trick. I just went by the tuning stability and did not measure the humidity. When the pitch is different across the tenor break, you know it is due to a change in humidity. Perhaps CW’s are more sensitive to humidity changes, I don’t know. This may be a good thing.

Jeff, my gut feeling is that your solution is the one that would work. I'm just not too excited about spending more money on the 9 piece system.

My other holdout is that the people at DC say that if it is very dry I should have to fill the water tank every week. I'm only filling it ever ~2.5 weeks so I may have an issue with the humidifier unit. Some more testing should tell.

(I'm thinking when the summer comes around and I have 60% humidity, I should close my eyes and not test my dehumidifier bar. Ignorance is bliss.)

dcb:

Yes, I noted that your humidifier was not calling for much water. That is why I thought of the doubled up pads. An interim step is two humidifiers in the piano or even humidifiers in the back of the piano without an additional humidistat. Take one thing at a time and see how it goes.