Baxi Potterton 47-393-41 Vertical Flues, Twin & Vertical Flue Systems, 120mm Min, Apart, Roof

Vertical Flues

8.0 Flue Options

(ii)

(i)

IMPORTANT: All flue systems must be securely supported at least once every metre. Suitable pipe supports are available as accessories.

	8.2	Twin & Vertical Flue Systems
	1. Maximum permissible equivalent flue lengths are:-
			(60/100)	(80/125)
	Vertical Concentric		10 metres	20 metres
	Vertical Twin Pipe		15 metres
	2. Any additional “in line” bends in the flue system must be
	taken into consideration.
	Their equivalent lengths are:-
	Concentric Pipes:
		135° bend		0.5 metres
		93° bend		1.0 metres
	Twin Flue Pipe
120mm Min		135° bend		0.25 metres
apart		91.5° bend		0.50 metres
Y	The elbow supplied with the standard horizontal telescopic
	flue kit is not included in any equivalent length calculations
	NOTE: Flue length is measured from point (i) to (ii) as
1m Min to	shown.
15m Max

(ii)

(i)

Vertical

Flues

(Twin Pipe)

600mm Min apart

T

1m Min

to

15m Max

Mini Terminal on Air Duct (sited in loft)

Total Equivalent Length =

A+B+C+1x90°Bend

All vertical and angled runs must be included, measured from the boiler adaptor (point X) to the joint with the flue terminal (point Y). One 91.5° bend or two 135° bends can be included without reduction of the flue length.

If further elbows are required the flue length must be reduced by the following amounts:-

1 metre for each 91.5° bend	(ii)
0.5 metre for each 135° bend

B

Roof

Terminal

C

Q

The total equivalent length for this example is

= 6.5 metres.

		AIR DUCT
	Equivalent	No of	Sub total
	Length Value	fittings/pipes
1m extension	1m	5	5.0m
135°bend	0.25m	2	0.5m
91.5°bend	0.5m	2	1.0m
	Equivalent Length Air Duct = 6.5m

This bend is equivalent to 1 metre

A

(i)

		FLUE DUCT
	Equivalent	No of	Sub total
	Length Value	fittings/pipes
1m extension	1m	5	5.0m
135°bend	0.25m	2	0.5m
91.5°bend
	0.5m	2	1.0m
	Equivalent Length Flue Duct = 6.5m

22© Baxi Heating UK Ltd 2012