The Glitch
Overview: A multiple boiler system has been
configured to supply multiple loads using primary/secondary piping.
Exercise: There are several
piping errors in this proposed installation. Can you spot at least 5 of them?
The Fix
1. Every boiler
in a multiple boiler system should have its own circulator that only operates
when that boiler is operating. The original schematic allows flow through all
boilers regardless of which are firing.
2. It may seem
simple to be sure the unions are installed between the boiler and the isolating
valves, but I've seen it otherwise.
3. Always
install the supply sensor for the staging controller on the distribution system
side of the hydraulic separation point, in this case the upper set of closely
spaced tees.
4. Every
secondary circuit should be equipped with purging valves to allow efficient
filling and flushing.
5. Always locate secondary circulators so they
pump into their associated circuit.
With this arrangement, the primary loop becomes the pressure reference
point and the pressure within the secondary circuit increases when the
circulator is on.
