[Shop-talk] Power-vented water heater kicks out.

[pethier at comcast.net]

We have a newish gas water heater with a power vent.  We built the vent line out of Schedule 40 and minded the length and number of bends shown in the docs that came with it.

Worked fine for a couple of months, then started kicking off.  Gave a 6-2 code which implies venting was inadequate.  

Took it apart and found a diaphragm switch which measures vacuum on the upstream side of the vent blower.  Tech support says that the switch is supposed to trigger at 3/4-inch of water.  Switch tests fine by mouth test, but a human can pull several inches of water.

Measured vacuum at 7/8-inch of water.  This says the switch is bad, so I asked them to send me a new one.  Went to Door County and Road America for a week.  Came back to find a large parcel.  They sent me the whole darn blower assembly.  

I installed the whole assembly and the same thing still happens.  Get this:  It runs OK if all the house windows are closed and either the exhaust fan in the basement or the clothes dryer is running.

Can I get an auxiliary fan that goes in-line in a Schedule 40 vent line?

Phil Ethier West Side Saint Paul Minnesota USA
1973 Triumph Stag LE22439UBW "uncle jack", Sapphire Blue
2004 Suburban 8.1, Sport Red, the only automatic of the bunch
2005 Lotus Elise, Bordeaux Red Pearl
2007 Saturn Ion 3 2.4, Berry Red
pethier at comcast.net
http://www.flickr.com/photos/pethier
http://www.flickr.com/groups/triumphtransamerica
http://www.mnautox.com
http://www.mntriumphs.org