If it is a urine odour and urineFREE can come into contact with the source of the odour then urineFREE will work.

If it is a urine odour and urineFREE can come into contact with the source of the odour then urineFREE will work.

You need to be very careful when applying any liquid with any of electrical appliance including a heater. Water and electricity don't mix.

We don't know how long or deep your heat ducting is but we DO NOT recommend you pour or spray urineFREE down the ducting. First of all turn off the heater. Then take a long handled sponge or mop and dampen the sponge or mop with urineFREE and insert it into the ducting and mop out. Let air dry, then rinse the sponge or mop with water and insert into the ducting again to remove any residue. Let dry again. Once dry turn on the heating and see if the smell is gone. Repeat if necessary.

We are assuming an animal has urinated into the ducting and hopefully urine hasn't travelled very far so you can get it all. If it has travelled to points unreachable by the sponge to mop you may need to get in a professional who has the equipment to reach further into the ducting.
urineFREE must make contact with all the urine to be 100% effective.