We just had our furnace serviced and had an igniter switch replaced in the mean time, they also took the water out of our expansion tank (not sure why). In doing so, they noticed that the PSI on the tank was set at 30 in which they said was too high for a two floor residential. They then put the PSI down to 22-25 (it fluctuates). After they left we had great heat on the first floor, but no heat on the second floor. We bled the heaters on the second floor about three times and all that comes out is a little air and no water. We have no idea what to do and were thinking that the PSI might not be registering right on the furnace and we're thinking of putting it back up to 30 PSI as it was originally because we had no trouble in the past getting heat to the second floor. Please help us! Any advice welcome!