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Quick Reference Installation Guide

For gas delivery to the boiler, we recommend using hard 

piping rather than flexible piping. If  you use flexible piping, 

ensure that the gas pipe size is appropriate for the maximum 

BTU input of  the boiler.

Minimum Gas Pressure

4" w.c.

Maximum Gas Pressure

14" w.c.

 

Size piping for sufficient sustained gas delivery at sufficient 

pressure to the boiler.

Recommended Supply Pressure at Full Load

Natural Gas

7"

Propane

10"

• 

Ensure that there is a minimum of  6 feet of piping 

between the boiler and gas regulators. 

•  Use a manometer to test that gas delivered to the boiler 

is delivered at sufficient pressure and that “lock up” does 

not exceed the maximum pressure.

• 

If  using a 5 psi to inches vented gas regulator, always 

oversize the vent pipe to prevent hunting of  the gas 

regulator when boilers are firing at lower output levels.

• 

We strongly recommend against using copper gas lines. 

In retrofits with existing copper gas pipes, we highly 

recommend replacing the pipes with black iron or 

stainless steel piping sized correctly for the boiler. If  the 

copper gas pipes must remain, clean and clear the gas 

piping of  any debris before connecting to the boiler. 

Failure to do so can result in a blocked gas valve. and 

inconsistent performance. 

 

Maximum Pipe 

Length by Model

½" IPS ¾" IPS 1" IPS 1¼" IPS

VX 110 (Natural Gas) 30'

125'

400'

1,600’

VX 110 (Propane)

90'

350'

1,000'

2,000’

VX 150 (Natural Gas) 20’

80’

200'

900’

VX 150 (Propane)

50

'

200'

600

'

2,000’

VX 199 (Natural Gas) 10'

40'

150'

900'

VX 199 (Propane)

30'

125'

400'

1,400'

1.  Place the vacuum breaker cap over the vacuum 

breaker opening and push firmly

2.  Fill the condensate trap with water.
3. 

Attach the trap to the drain hose, and tighten the 

drain compression (including washer)

4. 

Slide the trap over the boiler drain outlet, and tighten 

upper union nut. Secure the upper union nut with the 

outlet clip.

5.  Check for leaks.

Gas Supply 

(

Section 

3.12

)

Boiler Mounting 

(

Section 3.4 of the manual

)

Venting 

(Sections 

3.5 and 3.7)

Follow the venting specifications for the correct materials and 

venting lengths provided in the above sections of the manual.

• 

Ensure that sidewall configurations have adequate vertical 

separation, and that exhaust plumes are well away from all 

building air intake vents.

• 

Ensure that all venting material is sloped towards the boiler. 

PP venting must be sloped at a minimum of  ⅝″ per foot to 

ensure that no leaks occur via gaskets.

• 

Ensure that PPs venting is supported every 36″ (min).

• 

On longer horizontal runs of  PVC and CPVC, increase the 

grade to ⅜″ or more.

• 

Fully insert approved venting material into the boiler’s 

exhaust outlet. Then, tighten the clamp to lock the venting 

in place. For PPs venting, 

a transition adapter is not 

required.

• 

Check that the venting is 

securely attached to the 

exhaust flue of the boiler by 

pulling on the venting.

Important:

 To protect against wind loads, terminate 

exhaust venting as shown or use the appropriate direct 

vent kit.

Condensate Trap 

(

Section 

3.9

)

LWCO Errors 

To clear LWCO errors caused by air:

1. 

Ensure that there is no air trapped in the boiler and 

boiler piping.

2. 

On the touchscreen controller 

Status

 Menu, go to 

Clear Errors 

Yes

1.  Ensure that the boiler’s mounting bracket is securely 

bolted to the wall structure.

2.  Fasten the bottom of the boiler to the wall.

120-368 - Quick Reference Installation Guide - VX series

Important:

 Before turning off  the boiler, make 

sure it is in “Standby” mode.

Important:

 

Not applicable for construction 

heating. Parts such as fans, burners, and ignitors 

fouled by construction are not covered under 

warranty.

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