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Okay, so after lo these many years, I'm installing my first ever system on a grand - a Petrof IV, to be specific. In the past, I've mostly seen secondary dehumidifiers installed inside the action cavity, mounted on the key stop rail.

The instructions with the new system recommend installing it externally, under the key bed.

Pro's/con's? Is what I've seen the old way, and this is the new way?

I'll call D-C tomorrow when they're open, but I thought i'd pick y'alls brains in the meantime.

PS. Is there still such a thing as a "certified" installer? I emailed them a couple of weeks ago inquiring, and never got a reply.

The D-C installer list is right on their website. They even indicate which ones have the most experience.

Huh? The only systems that use two humidifiers are concert grands. The G6PS-38-SB is the system that is supposed to be installed on the Petrof IV. The one humidifier goes in between the two longest beams, the humidistat goes on the beam closest to the straight side, and the two dehumidifiers are placed at the tail, and near the end of the key bed by the belly rail. I have never seen a system installed with any component placed in the action cavity... even on installs that were done some 20 years ago.

Yes, there is still a "certified" installer program, which can be taken on their tech website.

Yes, you can become certified or whatever their term is for it. I've not done so 'yet' but I have installed a lot of them over the years. Never inside of the piano though and never under the key-bed.

I never believed in installing them inside of the action cavity for the sake of the action and pin block but, then again, I live in Michigan where it's cold 9 out of 12 months too! You're in Sandy Eggo... Lil different weather there...

Sorry, I meant secondary DEhumidifier.

Yes, I know about the list, but they also say that they won't honor the warranty unless the installation is done by a certified installer, so I want to be one. I look at the site and check it out.

I'm working on a Baldwin SF7 tomorrow that has a secondary dehumidifier installed on the key stop rail. I'll take a pic to show what I'm talking about.

Hi Jim,

I think this used to be very common practice, but placing a dehumidifier in the action is definitely not recommended under any circumstances; it could cause loose flanges and might possibly damage the block. I've seen lots of these "old school" installs and I always remove the rod from the action when I find them. However, if you feel that the action itself is sluggish due to high humidity, and if you feel that a standard DC system still doesn't do enough, a third rod can be placed under the keybed which might help. I have personally never found this to be necessary though. A good installation usually takes care of the whole piano.

I am certified and have installed approximately 100 systems. I highly recommend becoming certified - the online training is in-depth and covers lots of ground; it also offers lots of tips and information on wood and humidity that even veteran installers/technicians might not be aware of. I don't think you need to write them, just sign up at the website to take the training and tests.

And, unfortunately, I have found that many systems installed by others were not installed correctly. Often the humidistat is in the wrong location, which really minimizes the efficiency and effectiveness of the system. When Dampp-Chasers are installed correctly they work beautifully and help the stability of the piano immensely, especially here in NYC.

First off, Dampp-Chaser does not recommend installing a dehumidifier in the action cavity, as others have pointed out.

Secondly, Dampp-Chaser honors the warranty provided the system is installed by a professional piano technician. Many installers are not certified, and those systems are still covered. I'm certified, but I installed hundreds of systems prior to certification (and prior to DC having a certification program), and those are covered.

Thanks, guys. Now I know.

I've been studying the installation instructions carefully. The unit I got in for my customer's Petrof IV is a GP6S-38-SB.

Dampp Chaser has pics and all sorts of things readily available to technicians for anything that we need to know on these units along with what DC unit is recommended for what piano etc. You're a tech so register with their site and use that information. It's good info.

I, like Loren, have installed hundreds, probably thousands of them in the past 40 years. They've changed a lot over the past 15 years or so too, for the better in some things, worse in others, depends on what one likes, I think.

I don't install as many as I used too, only for the reason that people start out (customers) with great intentions but after a few months lost interest and then quit filling them up and taking proper care of it, leave the cord unplugged and then whine about the piano not staying in tune again... That gets OLD REALLY REALLY FAST... Explain it over and over and over and................

I'm taking it I can't take the certification course on the site until D-C gives me a login?

The school I went to actually had an unplug alarm for all its classroom pianos and concert grands. Annoying, but effective.

Cool! Tell us more!

Unfortunately, I don't have any technical info that I can share... I know zilch about electronics. But, they were battery operated, I believe, and quite loud.

Unplugged alarm sounds like something found in a hospital.

Correct. Either email them or give them a call, and they'll set you up. As for the technician's only section of the site, that requires a login and password too. Give them a call and they'll get you on track.

Keith,

I'm not sure whether one could buy unplug alarms off the shelf, but such a thing would be quite easy to make, using an AC mini-relay of the "normally closed" type, wired to the same plug as the Dampp-Chaser. As long as the unit is plugged in, the relay would be open, but when the plug is pulled, it would close (i.e. create a connection), and this could then be used to trigger a battery-operated siren. Pretty fail-safe, at least as long as the battery lasts...

I've made a similar unit to trigger certain events in my household when there is a power failure. The components cost around $25 in an electronics shop.

Does it get dry in Sandy Eggo? Like Jer, I've had some frustration with owners not keeping the system plugged in or filled - especially in institutional settings...

I find that installing a half system has been a good choice for those pianos that go crazy over the summer, but the owners don't want to mess with filling. (humidistat and drying bar(s)) If excess humidity is the problem, a half system may suit you and your clients better!

Don't forget the value of a bottom cover if the piano won't stabilize.

Ron Koval