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3. To check for fouled coils, remove pipe plugs from
blending valve base and cover, and install a gauge in
each connection. Temperature of water from heat
exchanger outlet piping should be approximately 200 to
215ºF when heater is being operated within its rated
capacity. (Temperature may be checked by using a
contact Pyrometer held against a smooth filed section
of exchanger outlet piping.)
LOW PRESSURE HEATERS: Steam pressures of from
2 to 15 psig may be checked by using the CAPACITY
ANÎ ADJUSTMENT TABLE found in your Heater Manual
to determine GPM and water temperature per your
operating conditions.
TEST PROCEDURE: With traps functioning efficiently,
and with flow adjusted for 60% of heater rated capacity
(approx. 5 psig differential across blending valve
diaphragm), the heat exchanger outlet water
temperature drops below 200ºf and continues to drop
as flow is increased to heaters’ rated capacity in GPM,
it indicates that coils are fouled and should be cleaned
or replaced. A coil cleaning Adaptor Kit is available
through your Leslie Representative, along with
instructions for its use. If quality of water being used for
Heater is poor, coils may foul rapidly indicating that
corrective water treatment may be necessary.
4. PROBLEM: INSUFFICIENT STEAM TO HEAT
EXCHANGER.
1. See Paragraphs 1 and 2 above of trouble shooting
guide.
2. LOW PRESSURE HEATER: Check steam reducing
valve operation, if one is used with Heater.
5. PROBLEM: EXCESSIVE STEAM PRESSURE TO HEAT
EXCHANGER.
1. LOW PRESSURE HEATERS: Check steam reducing
valve if one is used or steam source supplying heater.
6. PROBLEM: EXCESSIVE RISE IN WATER
TEMPERATURE ABOVE HEATERS’ SETPOINT
OCCURRING AT LOW FLOWS.
1. The above problem may occur if Heater Controlled
Temperature is overset due to:
a. fouled coils
b. drop in inlet water supply pressure
c. adjustment of controlled water temperature while
exceeding Heaters’ rated capacity in GPM.
See Paragraphs 1 and 2 of the second problem for
further information.
7. PROBLEM: EXCESSIVE DROP IN WATER
TEMPERATURE BELOW HEATERS’ ADJUSTED
SETPOINT OCCURRING DURING LOW FLOW.
1. See Paragraph 1 of Problem 2 above.
2. Inefficient trap operation or increase in trap discharge
drain piping backpressure. See Paragraph 2 of
Problem 3.
3. Too little gain. Readjust gain setting as shown in
Paragraph 2 of Problem 3.
NOTE: A 3ºF change in inlet water temperature to Heater will
produce a change in the Heaters’ adjusted water temperature
of 1ºF.
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