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110331-07 - 8/23
PHTM II
Combi Installation, Operating & Service Instructions
Appendix C
Special Requirements For Side-Wall Vented Appliances In
The Commonwealth of Massachusetts
IMPORTANT
The Commonwealth of Massachusetts requires compliance with regulation 248 CMR 4.00 and 5.00 for
installation of side-wall vented gas appliances as follows:
(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or
structure used in whole or in part for residential purposes, including those owned or operated by
the Commonwealth and where the side wall exhaust vent termination is less than seven (7) ft. above
finished grade in the area of the venting, including but not limited to decks and porches, the
following requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETECTORS. At the time of installation of the side wall
horizontal vented gas fueled equipment, the installing plumber or gas fitter shall observe that
a hard wired carbon monoxide detector with an alarm and battery back-up is installed on the
floor level where the gas equipment is to be installed. In addition, the installing plumber or
gas fitter shall observe that a battery operated or hard wired carbon monoxide detector with
an alarm is installed on each additional level of the dwelling, building or structure served by the side
wall horizontal vented gas fueled equipment. It shall be the responsibility of the property owner
to secure the services of qualified licensed professionals for the installation of hard wired carbon
monoxide detectors.
a. In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl
space or an attic, the hard wired carbon monoxide detector with alarm and battery back-up may
be installed on the next adjacent floor level.
b. 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.
2. 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.
3. SIGNAGE. A metal or plastic identification plate shall be permanently mounted to the exterior of
the building at a minimum height of eight (8) ft. 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”.
4. 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.
(b) EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled “Equipment Not Required To Be Vented” in the most
current edition of NFPA 54 as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room or
structure separate from the dwelling, building or structure used in whole or in part for residential
purposes.
