Roberts Gorden UHA[X][S] 60 Vertical Venting, Length Requirements, Maximum Vent Lengths

UHA LOW PROFILE UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL

•In the event that the requirements of this subdivision can not be met at the time of completion of installation, the owner shall have a period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery operated carbon monoxide detector with an alarm shall be installed.

Approved Carbon Monoxide Detectors: Each carbon monoxide detector as required in accordance with the above provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certified. Signage: A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment. The sign shall read, in print size no less than one-half (1/2) inch in size, “GAS

VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS”.

Inspection: The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the installation unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of 248 CMR 5.08(2)(a)1 through 4.

6.6 Vertical Venting

Vertically vented heaters can be common vented (up to four heaters).

For vent lengths greater than 5' (1.5 m), condensation will form. Insulation is recommended and condensation drains may be desired. Venting through the top of the heater cabinet is not recommended if vent lengths are longer than 10' (3 m). In this case, vent from the rear of the heater cabinet then run the vent vertically and use a condensate drain at the bottom of the vertical vent. Vent pipe must be sloped 1/4'' (.6 cm) for every 1' (.3 m).

For 4'' (10 cm), an approved vent cap (P/N 90502102) must be used.

For 6'' (15 cm) common vent, an approved vent cap (P/N 90502103) must be used.

For common vertical venting of more than two heaters, See Page 18, Figure 11.

A vent shall not extend less than 2' (.6m) above the highest point where it passes through a flat roof of a building.

6.7 Length Requirements

If using vent lengths greater than 5' (1.5 m), condensation will form in the vent pipe. Insulation and additional sealing measures (high temperature silicone at all seams) are required.

The entire vent should be insulated with foil faced fiberglass insulation (1/2" thick, 1-1/2# density minimum).

6.7.1 Maximum Vent Lengths

Model UHA[X][S]	Model UHA[X][S]	Number of Elbows
30 - 60	75 - 125
25 ft (7.6 m)	40 ft (12.2 m)	1
20 ft (6.1 m)	35 ft (10.7 m)	2
15 ft (4.6 m)	30 ft (9.1 m)	3
10 ft (3.0 m)	25 ft (7.6 m)	4
5 ft (1.5 m)	20 ft (6.1 m)	5

6.8 Vent Material

Vent material may be single wall 26 ga. (minimum) galvanized steel or equal thickness stainless steel. Completely seal all joints, refer to Page 14, Section 6.3.

If penetrating a combustible wall or roof, a listed thimble with 2" (5 cm) clearance must be used. Where local codes permit, a single section of type B-1 vent material may be used at the roof or wall penetration instead of a thimble. Ensure vent manufacturer's clearance from vent material is maintained. Seal annular space of the type B-1 vent as well as all joints in the remaining vent.

6.9Replacing an Existing Heater in a Venting System

When replacing an existing heater in a venting system, the venting system may not be properly sized to vent the new heater. The following steps must be followed with each appliance connected to the venting system placed in operation, while any other appliances connected to the venting system are not in operation.

1.Seal any unused openings in the venting system.

2.Inspect the venting system for proper size and horizontal pitch, as required by the NFPA 54/ ANSI Z223.1 - latest revision, National Fuel Gas Code (US) or Standard CSA B149.1 Natural Gas and Propane Installation Code (Canada) and these instructions. Determine that there is no blockage or restriction, leakage, corrosion and other deficiencies which could cause an unsafe condition.

3.Close all building doors and windows and all doors between the space in which the appliance(s) connected to the venting system

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