Fieldpiece DDSM1 - Draft Simulator User Manual download pdf

Description

Correct pressure switch operation is integral

to the safety of a furnace environment.

The DDSM1 teams with your accurate

manometer to accurately test pressure switches.

The DDSM1 creates a negative pressure

(vacuum) and detects a closed switch. Your

manometer tells you what the pressure is when

the switch activates.

General Setup

Fieldpiece

Draft Simulator

OPERATOR'S

MANUAL

Model

DDSM1

Controls and Ports

A Pressure dial (Clockwise increases vacuum.)

B Ports to negative side of switch and your

manometer. (Close one OFF if only using one.)

C Power button: High Speed>OFF>Low Speed>OFF

(some models use a rocker switch: I=Low, II=High)

D Closed-switch LED indicator.

E Jacks to switch terminals.

Functions

Test a Pressure Switch

WARNING: Turn o power to furnace prior to

testing to avoid low voltage shorting.

1. Connect leads to normally open and com-

mon terminals of the pressure switch. It

does not matter which lead goes to which

terminal.

2. Connect both hoses to the ports on the top of

DRAFT SIMULATOR. Connect one hose to the

negative side of the pressure switch and the

other to your manometer. It does not matter

which hose is connected to the manometer

and the pressure switch.

3. IMPORTANT: Before starting the DRAFT

SIMULATOR, ensure the pressure dial

is completely open by turning the dial

counter-clockwise as far as it will go.

Turn on and "zero" your manometer.

There are two major speeds to accommo-

date dierent pressure switch ratings – a

low speed and a high speed. The speeds are

accessed alternately by pressing the power

button multiple times as shown below:

OFF – HIGH – OFF – LOW

4. Turn on the DRAFT SIMULATOR. It is a good

idea to start the DRAFT SIMULATOR in high

speed to warm-up the motor for 10 seconds.

5. Set the DRAFT SIMULATOR to the major speed

needed for testing the pressure switch. Use

low speed to test pressure switches rated

between -0.10 inches of water column and

-1.50inWC. Use high speed to test pressure

switches rated 1.50inWC to 12.00inWC.

6. Slowly close the pressure dial by turning it

clockwise (increasing the vacuum) paying

attention to the indicator light on the front

of the DRAFT SIMULATOR and the readings

on the manometer.

7. The light will come on when the pressure

switch closes. Note the reading on the ma-

nometer. Manufacturers have a rating when

the pressure switch should close. A good

pressure switch will close within 10% of the

manufacturer’s rating.

8. To see when the switch opens, slowly open

the pressure dial by turning it CCW. When the

light of the DRAFT SIMULATOR goes o, note

the reading of the manometer. The reading

should be within 10% of the rating on the

pressure switch.

NOTE: Most pressure switches have bleed ports

in them to drain moisture. This also helps to

avoid excess pressure created by the draft

inducer and controls the amount of pressure

required to close the switch. The amount

of pressure required to close and open the

switch should still be within 10% of the

manufacturer’s rating. The pressure required

to close the switch should never exceed the

amount of pressure created by the draft

inducer.

NOTE: Many pressure switches have an orice

in the port. This increases the time it takes to

close or open the pressure switch. This does

not mean it takes more or less pressure to

close the pressure switch. The pressure switch

should still close and open within 10% of the

rating.

NOTE: Dual-port manometers are usually setup

to use the positive port (P1) with the DRAFT

SIMULATOR.

Indications of a Pressure Switch out of

calibration, weak or bad diaphragm or a bad

micro switch in the pressure switch:

o The pressure switch will not close or open

within 10% of its rating.

o The indicator light on the DRAFT SIMULATOR

“ickers” on and o rapidly.

o Manometer readings uctuate when no ad-

justments are made to the pressure dial on

the DRAFT SIMULATOR.

o The measured readings are greatly aected

when the hose to the pressure switch is

pinched.

Pinch Test - Proving the

Diaphragm

o Test the pressure switch and note the ndings

using the DRAFT SIMULATOR.

o Pinch the hose closed to the pressure switch

while performing the test.

o If the pressures dier more than 20% from

the original ndings, you may have a bad,

cracked, or leaking diaphragm in the pressure

switch. If the pressure doesn’t dier you may

have a blocked bleed port.

Prove or Rule Out the Inducer

o If the pressure created by the inducer mea-

sures more than enough to close the pressure

switch but the DRAFT SIMULATOR proves

the pressure switch to be good, the inducer

may not be providing enough cfm (cubic feet

per minute) to close the switch. The inducer

should be replaced.

inWC

One hose goes to manometer.

One hose goes to

negative side of switch.

Leads go to switch terminals.

(normally open and common)

1 2

Fieldpiece 1

Summary of Contents

Page 1 - Fieldpiece

01060207030804090510DescriptionCorrect pressure switch operation is integral to the safety of a furnace environment.The DDSM1 teams with your accurate

Page 2

11161217131814191520Calibrate an Adjustable Pressure Switch1. IMPORTANT: Be sure to use an adjustable pressure switch that will calibrate to the pr

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Fieldpiece DDSM1 - Draft Simulator User Manual

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Summary of Contents

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