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I recently started another thread ( link ) describing a damp-chaser experiment, but with a nonstandard installation. Here are the first results with a correct installation. The present readings are between the last 2 red dots on the following 2 graphs.

Last night I set up the system just before a dinner party. Here is what it looks like at the location of the controller. This is the setup used by the tech who fixed my original installation, except that he used Velcro tape instead of screws. (My original installation was done wrong. See this link ).



After the party was over I checked my data loggers. This is what I saw:

Here is the room humidity. For the dinner party I placed the coffee table humidistat in a different location (wife did not want it on the coffee table):



Here is the reading from the data logger placed on the front beam underneath the piano:



Needless to say, I was not happy about this measurement. During the course of around 5 hours (between the last 2 red dots), the humidity was mostly below 35%, and sometimes in the high 20’s. But, as you will see in the next plots, it changed overnight, becoming more regular but still very low.

Here is the coffee table reading overnight (after the party I placed that data logger back in the center of the coffee table):



Here is the reading on the front beam underneath the piano:



Again, the numbers are low, mostly between 28% and 35%, but increasing to 30-39% by 8am in the morning.


At this point I think it is worth repeating some remarks made by Ori when I posted last December ( this link ). Among other things, he said:

My guess is that the problem with my current installation (which does not have an undercover) is that the controller is too close to the rear reservoir. So, I am now taking measurements with the controller moved a bit further from the rear reservoir and closer to the front. I will post these results next.

Well, it is 2:30AM and I now have strong doubts about everything I have done so far. I'll explain below. But, in case I'm wrong, and in the interest of completeness, I will post my final readings.

When I wrote the previous thread, I had had my system running all day with the controller in a slightly different location. I read out the data loggers late in the evening and obtained the plots below.

Regarding the new location of the controller: For simplicity, I used the existing screw hole, placing the left hand screw of the controller in the screw hole that was formerly the right hand hole. This actually moved the controller over about 6 inches, which was more than I wanted, but it was easy to do.

Here are the readings from the coffee table logger (as usual, the new data are between the last 2 red dots):



And here are readings of the logger on the front beam underneath the piano:



As you can see, the data are erratic at the start, then there is a period of about 6 hrs where the RH oscillates between 34-46%, then it is erratic again.

I assumed that the controller was now too far from the rear reservoir, and that if I simply put it in between the two locations (in the middle of the 6 in interval) everything would be fine. But I never got that far. Here is what happened:

As I was moving the controller, I placed it back in its original location (as in the first picture in this thread), and was suprised that the heater rods were not on since previously this had led to very low RH. In fact, I held the controller at various locations and nothing I could do would make the heater rods come on. I even held the controller with the top right next to the top of the reservoir -- the heater rods still would not come on. Finally, I brought over an electric tea kettle, boiled water, and, when there was warm moist air coming out, I put the top of the controller in its path. The heater rods finally came on. Then I placed the controller on the floor, where I was reading 31% RH, and felt the heater rod. It stayed hot, like it was receiving current, for 8-10 minutes. Then it abruptly cooled down.

Based on this, I am now wondering if the heating portion of my controller is malfunctioning? I plan to call dampp-chaser corp tomorrow to ask them about this.

What you need to measure is the resulting EMC of the wood as affected by the readings of the air you now see.

The condition of the air is only important as it is related to the resulting condition of the wood.

After all it is the condition of the wood we are concerned about.

What measurments have you taken of the wood?

I can't explain these results.

The first place to start is with the tech who installed the system. It's much easier to investigate such problems onsite, rather than miles away with just photos.

Also, you've modified the original installation (sensibly, as far as I can tell), but maybe something else isn't connected right.

It looks like the RH goes out of range only at night. Is that right? Does your furnace switch to a lower temperature at night? It shouldn't matter, but again, we need to see the whole picture to understand what's happening.

I also don't understand Ori's recommendations to have the 'stat close to the water tank. When you had that configuration, you didn't get drier RH levels than you have now.

Oh, and the Velcro is the standard installation method for the 'stat; it comes with it. You can also use the screws.

--Cy--

If I were installing this system I would position the humidistat on the opposite side of the same post you have it on now. As with the first installation pictures you posted, it's still too close to a water tank.

Cy,
The thermostat in that room is set at 64 deg. The heat is radiant heat from beneath the floor -- it is very stable. Temperature changes in the room are due mainly to the house heating up in the daytime sun. FYI we draw two layers of shades when we leave for work, so that keeps the room environment pretty stable.

Regarding the velcro: the tech who fixed my installation many months ago used the velcro tape. Then I left for a few weeks and when I returned was sad to see the controller hanging in the air several inches below the soundboard. The problem was that the sticky side separated from the wood. I never could make that tape stick. For a time I used some slings to hold up the controller, but I had to be careful not to impede the air flow through the top holes, and with slings (fashioned from tape) it is hard to get the controller to stay up high enough. So I finally decided to use 2 screws to position and hold the controller.

Mr. Kia,
I tried that location once. I don't remember the results. But I can tell you that, recently, I have found that even with the top of the controller placed a bit above the beam, there still seems to be a noticable difference in results in my piano when there is a beam between the reservoir and the controller.

Today I spoke with Roger from dampp-chaser corp. We've talked at other times over the past several months and he has been very helpful and generous with his time. He said that there is not necessarily anything wrong with my controller, that I might just be observing slow sensor response. He also said that he suspects an undercover would help a lot, and he offered to send me one at no charge to see if it would solve my problem. I hope to have it installed before I leave town for Thanksgiving and be able to post the new measurements when I return from the holiday.

Every Humidistat that I ever put on with just the velcro, regardless of cleaning, has fallen off. Screws and velcro make for a quiet "stat" free from vibration.

DC ststems cycle within a certain Humidity range. I'd recite numbers now, but I'd have to look them up.

Regardless, the humidity rising and falling is the natural cycle within a certain range.


What is important is the EMC of the wood as a result of exposure to that cycle.

It is well understood among veteran installers that the humidifier portion of the system struggles in grand pianos. That is a good reason for installing the undercover. Or, supplimenting by humidifying the enviroment around the piano.

Most people do not put a logger underneath the piano so....the finer details of what is happening is not usually the subject of conversation. I am reasonably sure that these conditions, more or less, exist in all grand systems.

Keep in mind, it is the resulting EMC of the wood and the stability of that EMC that is the goal.

Moving the humidistat away from the water tank and toward the rim of the piano will result in the Humidifier portion staying on longer in dry climate. Adjust as necessary or reasonable.

Glad you got a good response from Dampp-Chaser. I've been very impressed with the company's products and support.

--Cy--

Barganax: Glad to hear you're getting the undercover. I'm very curious to see your results with the undercover installed. My tech felt VERY strongly that this addition would make the whole system so much more efficient.

Larry,
Thanks for the comments. I did not know if my velcro experience was unusual or not.

Regarding supplementing/humidifying the environment, I wish I could do that but it is difficult for me. The room is big (20' x 30'). There are windows and patio doors that my wife likes to keep open except in winter to keep the room cool. There is no water supply if I should want to have a humidfier or humidifiers that I don't have to constantly fill with by hand. And the openness of the room with the windows open would mean the humid air would not be trapped anyway.

Someone commented in another thread that dampp-chasers don't humidify the hammers. Is this true? I would have thought that, with the lid down, the trapped humidity would reach there...

Mr Kia:
Regarding your suggestion to put the controller on the opposite side of the beam, I had not done it in a long time, so I decided to try it again. Here are the results of 12 hrs running before I had to leave town. Note that, unlike all my previous graphs, these are taken with the lid down.





Given the dryness of Santa Fe I am reasonably satisfied with these results. In my mind it be nice if the low reading did not drop below ~35%, but what is shown here is only for 12 hours anyway. I am leaving it like this while I am out of town and will post the results when I return.

Of course, what really matters is how the system operates all year long. There are many days our area where the RH is in the teens and 20's. So I am still looking forward to monitoring the situation with an undercover in place and seeing how stable the microclimate is over the long haul.

With open doors and windows that allow air movement, an under cover is especially called for.

barganax,

I really appreciate the work you have done here. Information is always a good thing - especially because I would guess few of us even have one, not two data loggers to check installations.

I'm at a loss to explaing the erratic nature of some of you graphs - considering that the "out of the norm" readings seem to be when the humidifier portion of the system is running amok. Again, Roger would be the person to ask.... Has he been able to study the graphs you have made?

This has really made me rethink some of the installations that I have out there. Some seem to be more stable than others, and your work gives me a bit more information to work with!

Keep us posted, I find this VERY interesting...

I'm very interested also since I'm trying to decide if I should install one on my AF grand with winter approaching. The RH inside my grand right now is at 50%.

I picked up my desert spring humidifier last night. $325 with the auto flush and current sensor.

Super simple and elegant design. Think of a Venta that fills and washes itself, and that uses the warm air from your furnace to evaporate the water. It's true it will only run while the blower is on, but since my thermostat cycles the blower on several times an hour, I don't see that as a problem. I suppose I could simply leave the blower running on super dry days,so the desert spring would then act just like a venta and use room temp air. Seems wasteful though.

Thing looks very simple to install too, if you can use an electric drill, a screwdriver, and sheet metal snips. Oh, and you have to hook up the water line, but that's pretty simple.

I'll let you know what my increase in humidity is in a week. Right now we're in the high 20's at best, and it's not even winter yet.

Todd

edit. Sorry. Today it's actually 50% outside, temps in the mid 70's. It's been in the 20's. I'll check my humidistat when I get home. Curious if my house went up that much.

There is an EMC chart on my web site anyone can download and print.

I think it is a usefull perspective.

http://www.ejbuckpiano.com/Pages/Resources.html

Larry

There are holes through the soundboard where the "nose bolts" go through it, and the hammers strike the strings by coming up through an opening at the front of the soundboard. The humid air also dissipates around the rim of the piano and into the room, even through the undercover. It will reach the hammers.

If you've ever seen a smoke-damaged piano, you'd see proof of how air migrates through it...

--Cy--

Smoke is one thing Cy, difusion of the humidity is another. I would never say the dampp chaser does nothing for the hammers, but with the lid down, the airspace inside a piano is fairly dead. Simple enough test, put your humidistat in the piano and close the lid, then check it when the dampp chaser is on a humidify cycle.

Mine didn't budge more than 1% from the ambient room humidity after an hour, but when I put it under the piano on a beam, it went from 27 to 45% in about 15 minutes. Also was 3 degrees warmer. It may be that after a lot of cycles the inside under the lid would go up a couple of points, and I'll check that tonight, but I have my doubts. The soundboard limits airflow from underneath and the lid isn't air tight.

Not complaining, I love having the system.

Todd

You would likely need to keep the lid shut for a week or so, before the RH above the soundboard becomes more in line with the underside of the piano, than with the room RH.

From my own experience while the systems 'moderate' swings experienced in the action cavity on grands, while on uprights they offer much more precise control of RH in the action.

Well, I haven't opened it for three days, but it's so humid right now I'm not sure this is a valid test. I also put in the outflow and inflow on the furnace for my humidifier today. Now I need to get the water line in place. Plumber is coming tomorrow. I think my experiment may be useless. Oh well.