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 (h) Recheck limit and safety controls; then ignite the HTW generators.
Slowly heat the HTW generators' refractory and the system water. During this
period, maintain combustion controls on manual operation; do not change to
a u t o m a t i c control until after reaching operating pressure-
(i) As the system heats, the system water expands. This may cause the
water in the expansion tank to reach a higher than permissible level. I n t h i s
case, blowdown as required.
( j ) Check operation of the temperature control valve in maintaining
system water temperature by recirculating return water through the blending
line.
(k) Check operation of the automatic bypass val v e in maintaining proper
flow through the HTW generators.
3.2 Startup Procedure for Separate Pumping Systems. The startup procedures
for a separate pumping system are similar to those for a combined pumping
s y s t e m , except for the following differences.
(a) During the warmup period, c i r c u l a t e all water returned from the
system through the HTW generator. No return water should go directly to the
expansion tank.
(b) After the system water reaches a temperature of 200F, circulate all
water through the boiler and none through the distribution system. This
permits raising the pressure in the expansion tank to normal operating
conditions with a minimum firing rate.
( c ) After reaching operating pressure, circulate water through the
distribution system at approximately 25 percent of normal rate.
( d ) As the return water temperature drops, increase the firing rate as
required to maintain operating pressure in the expansion tank.
(e) Follow the above described procedures while increasing flow rate
through the distribution system as the return water temperature continues to
r i s e . T h i s will establish normal operating conditions.
While the system Is being warmed up, check the
3.3 Warmup Precautions.
f o l l o w i n g conditions:
( a ) Performance of expansion joints or loops.
(b) Performance of hangers, supports, guides, and anchors.
(c) Free expansion of headers and piping in the expected directions and
in the proper amounts. If any restrictions are noted, shut down the system
and provide proper clearance.
While the system is in operation, check the following
4 NORMAL OPERATION.
equipment.
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