I have an odd problem with my tankless Weil MacLain water heater. It seems that in the winter the water fill doesn't work right. I have had the unit checked out by the servicing company and received two different responses. The first guy told me I needed to bleed the system every week. The second told me that I needed to make sure the water level was at or above the level mark and that whoever plumbed the system didn't get the pipes correct. I think I believe the second guy more. However, over the summer, I didn't have too much trouble with it. Now that it is winter, it seems that the system doesn't fill properly. Every time I want to shower, I have to go down to the basement and fill the water tank. Why does this occur more in the winter? And, how do I fix it?