Security & Fire Protection Systems/Napco MA900


Hi Dave,

I have a hardwired alarm system for all the doors and windows in my home. Also, it has three low heat sensors and thermostats that trigger an alarm when the temps drop below the preset.

I did some home renovations and disconnected two of the low heat sensors, the former owners would go away in Winter while I do not. Also, I had to bury a few window alarms when replacing the windows..... So I now have an inoperable system.

My questions are;

Is it safe to just "bury these wires in the wall"?
Would you recommend pulling all the wires out if possible?
Would you recommend repairing this older system, getting a newer one, going wireless?
I have the NAPCO MA 900 with three keypads.

Thanks for your input!


Hello Phil, and I hope you're staying warm way up north.

You have several questions, but they're inter-related, so I'll just tell you what I think.

First, your NAPCO MA 900 is a control that was popular in the early 1990's, so it's likely been in operation for 20 years or more. That in itself isn't bad; a lot of these older panels seem to work forever. But the reality is that nothing lasts forever, and eventually it'll die. (What I see a lot is that the older keypads wear out, and it's nearly impossible to find a replacement, so the control/keypad combination is what needs to be replaced.

Second, you have a completely hard-wired system, and with the window replacements, you've had some damage. This damage is hard for me to assess without knowing what types of window sensors were used, and how the wiring was originally run to the windows. But most likely, either the contacts (switches) that were on the old windows were lost in the replacement, or the wiring was damaged when the old windows were removed.

Now, if the wiring is intact and accessible, then you could likely just buy new window contacts. There are several types available, but which type is best is usually determined by the window. Here's a link to an application guide that may shed light on this for you:

Would I repair or replace? Tough question to answer without being able to inspect the system. My inclination would be consider updating the control and keypads, and if this is a do-it-yourself project, going with wireless to avoid having to fish new wiring through exterior walls (that should be heavily insulated, and therefore a pretty tough task).

On the other hand, you could call a local alarm provider to have a look-see, and get an opinion that way, too. You might get a sales-pitch, but I don't think you'd be obligated to pay to have them make recommendations.

If you're the do-it-yourself type, consider starting with an "alarm kit" like any of these:

Well, I hope this helps, and if you have follow-up questions, I'm happy to lend a hand.

Best Regards,


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Dave Neuweiler


The design and application of burglary and fire systems for homes and businesses. Helping alarm owners understand how their system works. Helping to troubleshoot false alarm problems. Questions about monitoring issues.


Over a quarter century in the industry. Experience in installation, service, and monitoring centers. Training manager for a national protective services company; director of education and training for a national trade organization for for alarm dealers.


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