Crown Boiler TWZ Seies Owner's manual

TWZ/CT/ODV Series
Oil-Fired Hot Water Boilers (Less Tankless Heater)
INSTALLATION SUPPLEMENT FOR BOILERS
EQUIPPED WITH HONEYWELL L7248L
“2012 COMPLIANT” BOILER CONTROL
These instructions must be afxed on or adjacent to the boiler
WARNING: Improper installation,
adjustment, alteration, service or
maintenance can cause property
damage, injury, or loss of life.
For assistance or additional
information, consult a qualied
installer, service agency or the oil
supplier. Read these instructions
carefully before installing.
DESIGNED TO LEAD
Manufacturer of Hydronic Heating Products
P.O. Box 14818 3633 I. Street
Philadelphia, PA 19134
www.crownboiler.com

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I Basic Information
A. What is this Supplement For?
This instruction manual supplement provides important information on the installation and operation of TWZ, CT and ODV
boilers equipped with a proprietary version of the Honeywell L7248L Aquastat®. This control is being used in order to comply
with the 2007 Energy Independence and Security Act (EISA). The L7248L-based system saves energy using a “thermal purge”
feature which rst attempts to satisfy a heating demand by using residual heat in the boiler before allowing the burner to re. In
addition, this control system offers the following new features:
Ability to operate two circulator zones without additional relays.•
Easily installed optional 120V FWZ/TWZ LWCO Kit #411000•
B. How to use this Supplement
All information and Warnings in the original manual still apply EXCEPT for the following:
Information in this manual completely replaces the “Wiring” Section (Section X in TWZ, Section IV in CT , Section VIIIa)
in ODV) in the original manual
Section XII (“Operation”) and Section XIV (Troubleshooting) in this manual includes information for reading, adjusting,b)
and troubleshooting the L7248L which is completely new.
TWZ Series boilers equipped with tankless coils continue to be supplied with an L7224A.c) These instructions do not
apply to this control; refer to the boiler installation manual and the Honeywell instructions provided with the L7224A.
INSTALL AND SERVICE THE BOILER IN ACCORDANCE WITH THE ORIGINAL INSTRUCTIONS EXCEPT
FOR THOSE SECTIONS LISTED ABOVE.
X. Wiring
(Replaces Sec. X in TWZ Installation Manual, Sec. IV in CT Installation Manual,
Section VIII in ODV Installation Manual)
WARNING
All wiring and grounding must be done in accordance with the authority having jurisdiction•
or, in the absence of such requirements, with the National Electrical Code (ANSI/NFPA
70).
Disconnect electrical power to the boiler and heating system before servicing. Positively•
assure that no voltage is present. Lock electrical boxes to prevent someone from
inadvertently restoring power before the heating system is safe to operate.
Never defeat or jump out safety devices.•
Protect each boiler circuit with a properly sized over-current protection device.•
Make electrical connections carefully according to the boiler’s wiring diagram and•
instructions.
Wire additional field supplied safety limits, such as low water cutoffs and temperature limit•
devices, in series with the 120V circuit used to power the boiler. Do not alter the boiler’s
factory wiring when adding an additional limit device.

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120 Volt Wiring1) - The boiler should be provided with its own 15A branch circuit with fused disconnect. 120VAC power con-
nections are made inside the L7248L as follows (also see Figures. 10.0 or 10.2 as appropriate for boiler model):
Hot (“black”) - Terminal “L1”•
Neutral (“white”) - Terminal “L2”•
Ground (“green” or bare) - Ground screw on case of L7248L.•
The circulator is either factory wired to the L7248L or the boiler is provided with a exible conduit “whip” that is factory
wired to the L7248L circulator connections. If the circulator is not already wired to the control, connect it as follows:
Circulator “Hot” - Black wire lead from “whip”•
Circulator “Neutral” - White wire lead from “whip”•
•
Low Voltage Connections2) – Low voltage eld connections are located as shown in Figure 10.0/10.2 and are as follows:
T-T• - Connect to a 24 volt heating thermostat or other “dry contacts” (such as a zone panel end switch) that close upon
a call for heat. Follow thermostat manufacturer’s instructions. To insure proper thermostat operation, avoid installation
in areas of poor air circulation, hot spots (near any heat source or in direct sunlight), cold spots (outside walls, walls
adjacent to unheated areas, locations subject to drafts). Provide Class II circuit between thermostat (or zone controls) and
boiler.
1,2,3• - Used to connect EnviraCom thermostat, or other EnviraCOM device, approved by Crown for use with this boiler
(refer to instructions provided with EnviraCOM device).
Adding a Second Circulator Zone3) - The L7248L provided with this boiler can be used to control a second heating or DHW
circulator zone. If this is done, make the following 120VAC connections in addition to those described above (also see Figure
10.0 or 10.2):
Connect a 120VAC heating or DHW thermostat for the second zone between L1 and ZR.•
Connect the circulator for the second zone between ZC and L2.•
See Part XII of this manual for information on conguring the control to respond properly to this second zone.
Low Water Cut-offs4) - A properly installed low water cut-off (LWCO) prevents burner operation in the event that there is
insufcient water in the boiler. Many jurisdictions require the installation of a LWCO, as does NFPA-31. Install the LWCO
in the supply piping immediately above the boiler with no intervening valves. If a probe type LWCO is used, observe the
LWCO manufacturer’s required clearances around the probe. Use a LWCO that is wired so as to interrupt 120volt power to
the boiler in the event of a low water condition.
Crown 120V FWZ/TWZ LWCO Kit #411000 includes the LWCO, ttings, and wiring needed to meet the above
requirements.
CAUTION
When making low voltage connections, make sure that no external power source•
is present in the thermostat circuits. If such a power source is present, it could
destroy the boiler’s control. One example of an external power source that could
be inadvertently connected to the low voltage connections is a transformer in old
thermostat wiring.
Do not attempt to use EnviraCOM connections for any purpose not explicitly permitted•
by Crown Boiler Company. Attempting to do so may result in unreliable operation and/
or damage to controls.
Do not use the transformer provided on the boiler to power external devices such as•
zone valves. Doing so may cause damage to the transformer.

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FIGURE 10.0: TWZ, CT BOILERS: CONNECTIONS DIAGRAM FOR L7248L AQUASTAT®