January 9, 2011 at 9:20 am
This is a very useful site. Thanks.
I recently had my water heater replaced. The previous and new water heater use forced venting via a 3" PVC pipe (~ 35ft long). There are two 90 and two 45 degree elbows. The motor at the top of the heater vibrates when it runs. We have changed the motor and it does the same thing.
The problem is that when the PVC pipe is connected to the motor and the motor is running, one can feel vibrations in the control box/gas pipe connected to the water heater. If the PVC pipe is disconnected (and the motor is running – for testing only), there are no vibrations in the control box/gas pipe.
Clearly the PVC pipe connection is stiff enough that motor vibrations are transmitting to the body of the water heater and to the control box/gas pipe. The installer, in consultation with Bradford White, placed two PVC rubber coupling – one close to the blower and the other at the middle point of the longest run of the PVC pipe. This has reduced the vibrations at the control box/gas pipe but not completely.
I’d appreciate any comments.
I’d welcome any suggestions.