4
Two Stage Boiler Control 255
Literature — D 255, A 255, D 001, E 000, E 200
Control — Microprocessor PI control; This is not a safety (limit) control.
Packaged weight — 1.0 lb. (450 g), Enclosure C, PVC plastic
Dimensions — 4-3/4” H x 2-7/8” W x 7/8” D (120 x 74 x 22 mm)
Approvals — Meets DOC regulations for EMI/RFI.
Ambient conditions — Indoor use only, 15 to 120°F (-10 to 50°C), < 90% RH non-
condensing.
Power supply — Class 2, 24 V ac ±10% 50/60 Hz 3 VA
Relays — 120 V ac 10 A 1/3 hp, pilot duty 240 VA 2 A
Sensors — NTC thermistor, 10 kΩ@ 25°C ±0.2°C ß=3892
included: Outdoor Sensor 070 and Universal Sensor 071.
Control accuracy — ±0.5°F (±0.25°C) with up to 1000 feet (300m) of 18AWG wire
to sensors.
Min. Boiler Supply
— Off, 70 to 170°F (Off, 21 to 77°C)
Differential
— 2 to 45°F (1 to 25°C)
WWSD
— 35 to 105°F (2 to 41°C)
Heating Curve
— 0.4 to 3.6
Stage 2 Delay
— 0:30 to 4:00 minutes
In North America: tekmar Control Systems Ltd., Canada
tekmar Control Systems, Inc., U.S.A.
Head office: 4611 - 23rd Street
Vernon, B.C. Canada V1T 4K7
Tel. (604) 545-7749 Fax. (604) 545-0650
All specifications are subject to change without notice.
Printed in Canada on recycled paper.
Product designs, software and literature are Copyright © 1994 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
Limited Warranty: tekmar warrants to the original purchaser each tekmar product against defects
in workmanship and materials when the product is installed and used in compliance with tekmar's
instructions. Thislimited warranty covers the cost of parts andlabour provided by tekmar to correct
defects in materials and/or workmanship. Returned products that are fully operational are not
considered a warranty case. tekmar also does not cover parts or labour to remove, transport or
reinstall a defective product. tekmar will not be liable for any damage other than repair or
replacementof the defective part or parts and such repairorreplacementshall be deemed to be the
sole remedy from tekmar. This warranty shall not apply to any defects caused or repairs required
asaresultofunreasonableornegligentuse,neglect,accident,improperinstallation,orunauthorized
repairoralterations. Incaseofdefect,malfunction or failure to conform to warranty, tekmar will, for
a warranty period of 24 months from the date of invoice to the original purchaser or 12 months from
the date of installation of the product, whichever occurs first, repair, exchange or give credit for the
defective product. Any express or implied warranty which the purchaser may have, including
merchantabilityandfitnessforaparticularpurpose,shallnotextendbeyond24monthsfromthedate
of invoice or 12 months from the date of installation of the product, whichever occurs first.
Replacements:tekmarcansendreplacementproductsifrequested. Allreplacementsareinvoiced.
Any possible credit for the replacement will only be issued once the replaced product has been
returned to tekmar.
Product Return Procedure: Products that are believed to have failed must be returned to tekmar
Control Systems Ltd. 4611-23rd Street, Vernon B.C. Canada V1T 4K7 when agreed to by tekmar.
The installer or other qualified service person must, at the owner's expense, determine which
Limited Warranty and Product Return Procedure
IftroubleshootingbecomesnecessarywiththeTwoStageBoilerControl255,followthetestingprocedureinstepfouroftheinstallation
procedure on page 2 of this brochure.
If the display window is flashing “Err” and the outdoor pointer, the outdoor sensor is either open or short circuit. The control is
programmedtoassumean outdoor temperature of 32°F (0°C)andcontrolthesupplytemperatureaccordingly. Ifthedisplaywindow
isflashing “Err” and thesupplypointer,the supply sensoris eitheropen orshort circuit. Ifthis typeof faultoccurs, thecontrol will turn
off its relays in order to shut down the heating equipment it is controlling.
If you do not think the control is operating properly, check to see that the settings have been made correctly and that the problem is
not a result of external causes. Make sure that all wiring connections are solid and the sensors are correctly located.
Testing and Troubleshooting
Technical Data
Before you leave
• Install the wiring cover over the wiring chamber and secure it with the screw provided. • Place the front cover on the control and
snap it into place. • Place this brochure, and all other brochures relating to the installation, in the protective plastic bag supplied with
the control. • Place the bag in a conspicuous location near the control for future reference. • It is important to explain the operation
of this control within the system to the end user, and anyone else who may be operating the system.
Item
Date
S/N
5
Pump /
Boiler 2
2
1
6
34
Boiler 1
No Power
789
Com
Sen Sup
SenOut
Sen
24 V Only
21
CR
Power
H11121
PRGM
FC
1
2
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
Two Stage Boiler
Control 255
Nº of boilers
Power Supply:
24V 60Hz 3VA
Relay Capacities:
120V 10A 1/3hp
The installer must ensure that this control and its wiring are isolated and/or shielded from strong sources of
electromagnetic noise. Conversely, this control does not exceed the Class B limits for radio noise emissions
from digital apparatus as set out in the Radio Interference Regulations of the Canadian Department of Communications. If this equipment does cause
interference, the user is encouraged to try and correct the interference by reorienting the receiving antenna and/or relocating the receiver with respect to
this equipment. Le présent numérique n’émete pas de bruits radioeléctriques dépassant les limites applicables aux appareils numériques de Classe B
prescrites dans le réglement sur le brouillace radioeléctrique édicté par le Ministére des Communications du Canada.
component has failed. The product must be returned complete withall of its components (sensors,
base,etc.). Products must be returned together with the proof of purchase to theoriginalpurchaser
whothen returns theproductto tekmar afterreceivinga Return Goods Authorization(RGA)number
from tekmar.
Pleaseinclude thefollowing information withthe product. The fulladdress oftheoriginal purchaser,
the RGA number and a description of the problem.
Fromthe U.S.A., in ordertoavoidcustoms charges, products must bereturnedvia US Post with the
package clearly marked with the RGA number, product type and the statement "Canadian Product
returned for
repair". For shipping purposes the product can be valued at one half list price.
1) If returned during the warranty period and the product is defective, tekmar will issue full credit
for the returned product less cost of missing parts.
2) Ifreturned during thewarrantyperiod and the productisfully operational, tekmar willreturnthe
product to the original purchaser for a testing cost of $30.00 plus postage.
3) If returned during the warranty period and the product is not damaged and is fully opera
tional, tekmar can take back the product for a return charge of 40% of the product's net value.
This request has to be specified otherwise the product will be returned with a testing cost of
$30.00 plus postage.
4) Ifreturned after the warranty period and the product needs repair, tekmar willrepairandreturn
the product. Repair and postage costs will be invoiced. tekmar's repair costs are calculated
at $30.00 / hour plus the cost of parts. If the repair costs will be more than $60.00 a repair
estimate will be sent to the original purchaser.
