I would suspect that the heat lamps are putting out infrared, some of which is in the wave length the IR cameras are capable of picking up. Can you turn off the camera IR LEDs independently to see what kind of image you get when the heat lamps are on without the built in camera illumination? Is the image acceptable that way? If it was you might be able to tie into the same power circuit via relay and I/O port to automatically accomplish this switching.
I should preface this with the fact that I'm just some dude with a theory but with no experience or professional knowledge in this area.
The presence of color is interesting. We know that heat lamps provide both IR and a significant amount of visible red illumination.
I began with the theory that you might actually have a day/night camera with an IR cutout filter. If this is not the case, then this message isn't worth the time you've already spent reading it :)
I wondered if there might be enough visible red illumination from the heat lamp to activate the IR cutout filter, returning you to the functionality of a color camera dominated by the visible red illumination.
I dug out my Arecont AV5155DN and put it in a dark room. I heard the "click" of the IR filter cutting out. Without external IR illumination, I could barely see the outlines of things in black and white. I don't have a heat lamp, but I figured I would try using faint red illumination by shining a flashlight through a stack of two semi-transparent red cups.
Perhaps this poor man's red illuminator doesn't put out enough visible red, because I never heard the "click" of the IR cutout filter cutting in. As I moved the illumination, I could see a bright spot roving about the B&W image.
So, I wanted to report my negative results but suggest this experiment was flawed because I had no heat lamp. An alternative approach is to have the customer stand near the camera after dark and click the heat lamp on & off. Does the customer hear the distinct "click" of the IR cutout filter engaging and disengaging? If yes, that could the issue.
Only if this is the issue, it leaves you with a challenge because you probably want to benefit of the IR illumination, which is now being excluded by the cutout filter, so that all you are benefitting from is the dim visible red illumination. If that's the case, you need to hear from a professional who understands camera settings and might be able to suggest how to keep the cutout filter from kicking in when you "know" that you want to be able to see the IR illumination.
The fact that the image is red means it is in color mode.
Is this a hikvision camera? What's the model?
The heat lamp might generate enough light that the camera is cutting back to color mode. One solution, if the model supports it, is to force night mode on a schedule.
If this is a cheap camera with no cutout filter, that implies that it's capturing all the illumination, making this mostly a cosmetic preference issue. Does the customer mind that it's pink as long as the scene is visible and they know that nothing is malfunctioning?
This is a very interesting problem since i am in horse country (Kentucky). Please let us know how this turns out. I was wondering if --assuming it exists-- you could check the Spectral Power Distribution Curves (SPDC) for the the heating units. Then match same with the response of the camera. It would be interesting to see where these lamps are on the SPDC.
As others have said, simply force it to B/W mode to alleviate the issue. This can definetely be done with this camera.