MODULAR STEAM QUESTION - DVW

David Van Wickler

I've been pouring through manuals and design this and design that and I just haven't found a logical reason NOT to include a hartford loop on each of a 5 modular steam boiler system. The system is 2 million BtuH (400 each)

The system includes a boiler feed pump (actually a duplex unit) and I do not agree with the ASHRAE design which includes check valves on each return (doesn't the harford loop do the same thing? But with pipe/pressure instead a disk?

Anyone have a reason that makes sense?

It's really too late, I set it up with individual hartford loops and circuit setters on each boiler to regulate the feed into them. I also installled LWCO and Pump relays on each boiler versus one pump control nestled in the middle.

The circuit setters are set simple for 20%, 40%, 60%, 80% and 100% open. Anyone done this? A little wedding of the water side and the steam side.

TY

DVW

David Van Wickler

Hartford Loops on Modular system

I've been pouring through manuals and design this and design that and I just haven't found a logical reason NOT to include a hartford loop on each of a 5 modular steam boiler system. The system is 2 million BtuH (400 each)

The system includes a boiler feed pump (actually a duplex unit) and I do not agree with the ASHRAE design which includes check valves on each return (doesn't the harford loop do the same thing? But with pipe/pressure instead of a disk?

Anyone have a reason that makes sense?

It's really too late, I set it up with individual hartford loops and circuit setters on each boiler to regulate the feed into them. I also installled LWCO and Pump relays on each boiler versus one pump control nestled in the middle.

The circuit setters are set simple for 20%, 40%, 60%, 80% and 100% open. Anyone done this? A little wedding of the water side and the steam side.

TY

DVW

Unknown

David, you have two questions here

The first one, Hartford loops are OK, but you will go through close nipples often in them, from erosion.

The check valves are there because the tank is vented. It keeps the water in the boiler when the pump ISN'T running. The pumps will be on and off all the time, without check valves. You really do need them.

Noel

David Van Wickler_3

check valves

Yes, the DUplex pump set has check valves in place but if there is a leack between the feed pump and the boilers, all boilers will go down. ASHRAE show a check valve on each boiler return and I feel that that would be unnecesary with the hartford loop set-up (and equalizer).