I am trying to determine why I smell gas at the top of my wall heater.
Last weekend I paid another service company to check it but they could
not troubleshoot the problem. He brought no gas detection meter just a
light and soap bubbles. They only wanted to sell me a new central
heating system for $3700 or replace the wall unit for $2000! I do not
smell it while the burner is heating as much as when only the pilot
light is on.

When I bought my house in May 2000, the previous owner put in two wall
heaters Williams model 2509612. At least once each year I have called
the utility company or heater service companies to identify the source
of the leak. I belive the regulator was replaced one time. There is no
obvious sign of a leak near the gas valve. There was a small leak once
at the pilot adjustment screw found by the utility company which was
treated by applying paste to the threads of the screw cover. I do smell
gas at the top of the unit where the heat comes out. Could that mean
the burner is not doing its job efficiently or the venting is not
correct? The burner says Bray A32609BN. The valve is a Robert Shaw
7000SRLC date code 9971 (not included in the recent recall). I did also
just send a request for technical support to Williams.

I climbed on the roof and put two new ventcaps on to replace rusty old
ones. Are these standardized or should they have a flow rating for
backpressure? I tried to smell for gas up there this weekend but I
smelled none. It was very windy though which might explain that.
Thanks for your help.

Possibly it is burnt gas not venting well, get a digital read out Co
meter and put it nearby.

Dish soap on joints will bubble with a leak. The gas Co will use a
meter and do a check for free.