For those interested in building a PTS flowbench...
Then I bought a 400cfm commercial bench with two liquid manometers. I hated it. Big blower motor and the liquid manometers were affected by weather hourly. Not repeatable enough for the testing I wanted to do. I went head first reading and learning everything I could about flowbenchs and decided to go with Bruce’s PTS bench. A buddy of mine cut all the wood for me in his shop for a couple cases of beer (he wanted nothing). Built it, wired it, and I know if I’m not over 1000 flow tests I’m close. Heck I’ve done 8 in a single day. To this day I never finished it as it should be final painted and the front doors installed. I can flow a head today and in August I doubt if it would vary 2 cfm because it’s an “orfice” bench not a “pilot” bench. Calibration is checked everytime I change the head mount but it never changes. I have the calibration plates so I check it. It’s an 8 motor bench that can test up to 36 inches and I’ll use that if I have a problem I can’t find. I can test up to a 525-540cfm head. I make my own head mounts out of 1/2 lexan and cylinder sleeves. I then drill them for bench mount holes and use a head gasket to lay out the bolt pattern.
Then I bought a 400cfm commercial bench with two liquid manometers. I hated it. Big blower motor and the liquid manometers were affected by weather hourly. Not repeatable enough for the testing I wanted to do. I went head first reading and learning everything I could about flowbenchs and decided to go with Bruce’s PTS bench. A buddy of mine cut all the wood for me in his shop for a couple cases of beer (he wanted nothing). Built it, wired it, and I know if I’m not over 1000 flow tests I’m close. Heck I’ve done 8 in a single day. To this day I never finished it as it should be final painted and the front doors installed. I can flow a head today and in August I doubt if it would vary 2 cfm because it’s an “orfice” bench not a “pilot” bench. Calibration is checked everytime I change the head mount but it never changes. I have the calibration plates so I check it. It’s an 8 motor bench that can test up to 36 inches and I’ll use that if I have a problem I can’t find. I can test up to a 525-540cfm head. I make my own head mounts out of 1/2 lexan and cylinder sleeves. I then drill them for bench mount holes and use a head gasket to lay out the bolt pattern.