Mud Dauber Screens for Furnace vents

During warm weather I keep protective screens over the round Suburban Furnace vents to keep out wasps, bugs, etc. The package in which the screens came in says they do not block air flow. However, the Suburban Furnace User's Manual says not to install screens over the vents.

Now that we are using our furnace I wonder if I should take off the screens or leave them in place. Best way to avoid misplacing them or their parts would be to leave them on. What do you think? Has anyone had a problem with the furnace while leaving screens installed during the cold nights when the furnace is on? Thanks.

The dome shaped ones appear to have the same opening area as the vents themselves so there should not be a problem. That said I have been told by several dealers that the use of the screens will void the warranty of the furnace. My preference is to use them in the warm weather when the mud daubers are active and you don't use the furnace much and take them off during the cold weather as the bees are not building nests then.

[Bill]

My guess - and that's all it is - is that the screens tend to collect lint (like a dryer screen) which reduces the airflow to the furnace. Naturally this would cause problems, so the furnace mfrs are leery of them. But if you are careful to keep the screens cleaned, my guess is that everything will be fine.

Bill