Step 6: Main Gas Shut-Off Valve Train - Eclipse ThermJet TJSR Series Design Manual

Self-recuperative burners

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Quick instruction manual (4 pages)

Table Of Contents

Table of Contents

2. Calculate the Blower Air Volume

The volume of air required will be dictated by the

maximum output required from the burner. This will be

the total of the air required for combustion plus the air

required for the eductor. The totals required are

shown on the appropriate datasheet. Multiply this

volume by the number of burners and this is the total

volume needed.

NOTE: A minimum of 10% safety margin should be added

to the blower capacity.

Exhaust

The eductor provided with the TJSR is capable of pulling

all the exhaust gas through the burner and when set up

correctly will give approximately neutral pressure in the

furnace chamber. Using this method it is not possible to

use furnace pressure control.

An alternative method, where more precise furnace

pressure control is required, is to pull only 90% of the

exhaust gases through the burner. The remaining 10% of

exhaust gas would exit through an auxiliary flue with

furnace pressure control.

The furnace pressure should not be too high; a positive

pressure will force a disproportionate amount of exhaust

gases through burners that are in the off or low fire mode.

Exhaust ducting should not be connected directly to the

eductor outlet. It's recommended that the exhaust duct or

cowl be at least 2" larger in diameter than the eductor

outlet. There should be at least a 2" vertical air gap.

Air Pressure Switch

The air pressure switch gives a signal to the monitoring

system when there is not enough air pressure from the

blower.

You can find more information on pressure switches in

Blower Bulletin 610.

■ Eclipse supports NFPA regulations, which require

the use of an air pressure switch in conjunction

with other safety components, as a minimum

standard for main gas safety shutoff systems.

WARNING